.38-.55 Winchester Lever Action
Rob L
believe) that is chambered in 38-55. This is a caliber I have never heard
of before, and I suppose finding new ammunition for this caliber would be
pretty tough. I also have two old boxes of ammo that came with the rifle.
Does anyone out there have any info on how this caliber compares to
something more modern? I would like to at least take it to the range and
shoot some targets to see how it shoots. Any info is appreciated
Thanks in advance
Rob L
-----------------------------------------------------------
Learn about rec.guns at http://www.recguns.com
-----------------------------------------------------------
BJamesjr
Winchester has chambered some of their commemoratives in this caliber, but the
ammo itself is also collectible so it is somewhat expensive. You can also fire
.375 Winchester ammo in the rifle, but you should not do this unless a gunsmith
inspects the gun and tells you that it is in good condition. If I had one of
these, I would reload for it.
D. J. D.
than a 375 Winchester but isn't as powerful. Components to reload the 38-55
are readily available. The SAAMI specification for the cartridge calls for
a .377 bullet but many people shoot larger diameter bullets in the belief
that it is necessary to fill the groove diameter of larger bores. The fact
is that with softer lead, the .377 bullet will easily obturate and gives
very good accuracy. I will admit though that the 38-55 was a cartridge long
before SAAMI became an organization. It's a fine cartridge for deer and
some may argue that it will take larger game than that although I would
personally opt for more medicine. The 38-55 is known for great accuracy out
to about 300 yards.
Don
Rob L <rlon...@yahoo.com> wrote in message
news:ah50f0$phu$1...@grapevine.wam.umd.edu...
> ...
heard
> ...
Larry Lnight
ammo should be available from Black Hills Ammunition as well as others. The
ammunition you received with this rifle might be to valuable to shoot up for
fun. I'd get an opionion from a collector. I'd also have the rifle looked
over by a competant gunsmith before making a trip to the range.
Larry K.
"Rob L" <rlon...@yahoo.com> wrote in message
news:ah50f0$phu$1...@grapevine.wam.umd.edu...
> ...
heard
> ...
-----------------------------------------------------------
Manfred Kaufmann
#
Any info is appreciated
#
http://www.reloadbench.com/cartridges/3855w.html
http://www.chuckhawks.com/38-55win.htm
Mercante, SASS # 40988
MTNMANN
still available. It is a low velocity heavy bullet, originally developed in
the 1880s. In the right gun it is extremely accurate.
mtnmann
John from MD
I have a Marlin in 38-55 and love it. The caliber gives more
performance than a 30-30 and has less kick than a 45-70 and works
great with blackpowder or smokeless loads. The only factory ammo made
today is I believe Winchester and it is very anemic at about 1100 feet
per second. It is accurate enough at 50 yards if that is all you want
to do with the rifle. The Old Western Scrounger may have some ammo for
it also. I reload all of my ammo and haven't bought any in some time.
I use mine in blackpowder shoots at 200 yards with a 270 lead bullet
and about 40 grains of blackpowder.
I think this is a very balance cartridge and some very fine rifles are
chambered for it.
Regards,
John from MD
Keith Whaley
Rob L wrote:
#
# I recently inherited an old Winchester Lever Action Rifle-(Model 84? I
# believe) that is chambered in 38-55. This is a caliber I have never heard
# of before, and I suppose finding new ammunition for this caliber would be
# pretty tough. I also have two old boxes of ammo that came with the rifle.
# Does anyone out there have any info on how this caliber compares to
# something more modern? I would like to at least take it to the range and
# shoot some targets to see how it shoots. Any info is appreciated
Hi Rob,
The proper designation, if there is any such caliber, would be ".38-55."
No dot before the 55.
".38" is the caliber, and "55" being the charge weight of black powder
originally used to load it.
Might the rifle be a model 94? In 1940 Winchester dropped the .38-55
from the list of calibers the m.94 was chambered in, but they have
reissued it in recent years. That's good news!
If you have a serial number, we can find out how old it is. For
example, list the number as 11387xx, replacing the last 2 digits with x's.
By the way, that caliber/cartridge was discontinued in 1970, but is
again listed in Winchester's latest ammunition catalog! It's a good
up-to-200 yard cartridge for medium sized game, and to put it in
perspective, if handloaded, it is _reportedly_ (Cartridges of the
World) a bit better than a .30-30 Winchester cartridge.
The figures below don't seem to support that contention, but perhaps
it's because of the larger diameter bullet... I don't know.
In any case...
Factory loads:
.38-55 ~ 255 gr. SP, 1320 fps 987 ft. lb energy
(this is as currently loaded by Winchester)
.30-30 ~ 170 gr. SP, 2200 fps 1827 ft. lb. energy
(twice the .38-55's energy!)
Handloaded:
.38-55 ~ 220 gr. SP, 1700 fps 1412 ft. lb. energy
.38-55 ~ 255 gr. SP, 1700 fps 1637 ft. lb. energy
(still, this is only about 90% of the .30-30's energy)
The larger bullet makes the trajectory much less flat than the
.30-30's, but still, for a brush gun or short range shots, it's
probably a formidable round! It is when you take a look at that long
cartridge, anyhow! <grin>
You have a nice gun, for which ammo is still available! Enjoy it!
Keith Whaley - gunsmith/owner
WHALEY's Gunsmithing
Westchester, CA
Alan S. Petrillo
#
# I recently inherited an old Winchester Lever Action Rifle-(Model 84? I
# believe) that is chambered in 38-55.
[snip]
# Any info is appreciated
The Old Western Scrounger <www.ows-ammunition.com> lists ammunition for
it. It's expensive, though. If you plan to do any serious shooting
with it you're going to want to load your own.
AP
--
Aviation is more than a hobby. It is more than a job. It is more than
a career. Aviation is a way of life.
A second language for the world: www.esperanto.com
Processor cycles are a terrible thing to waste: www.distributed.net
Adam Kippes
# The larger bullet makes the trajectory much less flat than the
# .30-30's,
The two factory loads you cited have all but identical sectional density
(.256 vs. .252) and, presumably, more or less identical shape... as one
might expect, Winchester lists the ballistic coefficient as .254 for the
two 170/2200 .30-30 cartridges and .354 for the .38-55 one.
The .38-55's, um, noticeable trajectory problem has to do with its
*velocity*, not its weight (or diameter or length - whatever you mean by
"larger"). In fact, if one posits the proverbial "all else being equal",
the heavier bullet will have the flatter trajectory, especially at
whatever one considers long-range for the particular cartridge.
# but still, for a brush gun or short range shots, it's
# probably a formidable round!
Better than a .30-30, anyway. Sounds like an interesting short-range
cartridge, e.g., lower recoil, but are you sure you would want to shoot
it two-hundred yards at *anything*? I mean, sure, it will retain a
greater proportion of its muzzle velocity downrange [1] but still, those
trajectory figures are scary! <g>
[1] Thereby increasing its advantage over the .30-30, always assuming
you can actually hit something with it. I don't know the .38-55's actual
diameter so I just used .38"; it wouldn't, perchance, be .357"? Sorry.
-- AK
--
Please reply to the newsgroup. That is why it exists.
Adam Kippes
# I recently inherited an old Winchester Lever Action Rifle-(Model 84? I
# believe) that is chambered in 38-55. This is a caliber I have never heard
# of before, and I suppose finding new ammunition for this caliber would be
# pretty tough.
Winchester Product Symbol: X3855. They list the one Mr. Whaley
described, which is a 255 gr. Super-X Soft Point at 2200 f/s.
-- AK
P.S. Someone should tell Winchester that the caliber is really ".38";
they do that with everything.
--
Please reply to the newsgroup. That is why it exists.
-----------------------------------------------------------
Keith Whaley
Adam Kippes wrote:
#
# In <ah50f0$phu$1...@grapevine.wam.umd.edu>, Rob L wrote:
#
# # I recently inherited an old Winchester Lever Action Rifle-(Model 84? I
# # believe) that is chambered in 38-55. This is a caliber I have never heard
# # of before, and I suppose finding new ammunition for this caliber would be
# # pretty tough.
#
# Winchester Product Symbol: X3855. They list the one Mr. Whaley
# described, which is a 255 gr. Super-X Soft Point at 2200 f/s.
#
# <http://www.winchester.com/>
#
# -- AK
#
# P.S. Someone should tell Winchester that the caliber is really ".38";
# they do that with everything.
Of course. They DO call the caliber .38. The actual bullet is
somewhere between .375 and .379" diameter, depending on who you believe...
They call the CARTRIDGE the .38-55 Winchester, which is historically proper.
What's the beef?
Keith Whaley - gunsmith/owner
WHALEY's Gunsmithing
Westchester, CA
-----------------------------------------------------------
Keith Whaley
Adam Kippes wrote:
#
# In <ah6al2$5rs$1...@grapevine.wam.umd.edu>, Keith Whaley wrote:
#
# # The larger bullet makes the trajectory much less flat than the
# # .30-30's,
#
# The two factory loads you cited have all but identical sectional density
# (.256 vs. .252) and, presumably, more or less identical shape... as one
# might expect, Winchester lists the ballistic coefficient as .254 for the
# two 170/2200 .30-30 cartridges and .354 for the .38-55 one.
#
# The .38-55's, um, noticeable trajectory problem has to do with its
# *velocity*, not its weight (or diameter or length - whatever you mean by
# "larger").
Yes, of course. I should have said "...given it's lower speed..." But,
it's reported excellent performance on game is largely due to the
diameter of the bullet.
Granted, if you don't have the speed, forget it, but handloaded, the
.38-55 DOES have nice performance figures! And, with a higher BC, it's
an interesting cartridge, indeed!
I think I'll buy some dies, and start looking for a lever action! <bg>
# In fact, if one posits the proverbial "all else being equal",
# the heavier bullet will have the flatter trajectory, especially at
# whatever one considers long-range for the particular cartridge.
#
# # but still, for a brush gun or short range shots, it's
# # probably a formidable round!
#
# Better than a .30-30, anyway. Sounds like an interesting short-range
# cartridge, e.g., lower recoil, but are you sure you would want to shoot
# it two-hundred yards at *anything*? I mean, sure, it will retain a
# greater proportion of its muzzle velocity downrange [1] but still, those
# trajectory figures are scary! <g>
Oh, not if you think of it as a short range cartridge, and don't try
to make a buffalo rifle out of it! It is what it is. Use it
accordingly, and it's a mighty fine cartridge!
By all accounts, inherently accurate too. It DID start out life as a
Ballard target round...
# [1] Thereby increasing its advantage over the .30-30, always assuming
# you can actually hit something with it. I don't know the .38-55's actual
# diameter so I just used .38"; it wouldn't, perchance, be .357"? Sorry.
#
# -- AK
Keith Whaley - gunsmith/owner
WHALEY's Gunsmithing
Westchester, CA
-----------------------------------------------------------
John from MD
# # believe) that is chambered in 38-55. This is a caliber I have never heard
# # of before, and I suppose finding new ammunition for this caliber would be
# # pretty tough.
#
# Winchester Product Symbol: X3855. They list the one Mr. Whaley
# described, which is a 255 gr. Super-X Soft Point at 2200 f/s.
#
# <http://www.winchester.com/>
#
# -- AK
#
# they do that with everything.
When I shoot my .38/55 in BP shoots, we are shooting at a 16 inch gong
at 200 yards. I am sure that the trajectory is almost as bad as a
bell curve considering how high I had to adjust the rear sight to hit.
However, when I load smokeless loads around 2200 fps, it is
extremely accurate and much straighter shooting. I have been able to
shoot clover leaf groups using Lyman sights a 270 grain tapered bullet
and a charge of RL7 powder. If I could keep only one rifle, this
would be the one that I would keep.
John from MD
MTNMANN
The most important factors in shooting is:
1. Knowing your range.
2. Knowing where your rifle shoots.
3. Having good sights to get a repeatable sight picture.
4. Loading your ammunition with consistency.
5. Being able to shoot with consistency (good trigger let-off).
Velocity has some effect if there is a wind, the higher the velocity the more
effect the wind has on wind drift.
Black Powder Silhouette shooters typically shoot rams at 500 meters (547 yards)
and can knock 10 for 10, where the trajectory is on the order of 17 feet high.
So there! Once you sight in your hight trajectdory at 200 yards, there is no
need to do it every time you go to the range.
mtnmann
Adam Kippes
# Trajectory has very little effect on accuracy.
That is simply not true, at least in the real world. The whole point of
a flatter trajectory is to allow for more accuracy at a given range.
Okay, and maybe to extend the practical range a bit up to the limits of
your own ability to hit anything.
# Velocity has some effect if there is a wind, the higher the velocity the more
# effect the wind has on wind drift.
I'm not sure whether "velocity", as used here, refers to the bullet's or
the wind's, but the faster the bullet, relative to the wind, the less it
is affected by the wind, i.e., the less it will drift and, therefore,
the higher its average velocity - between start and stop - relative to
the earth. In fact, it will get there in proportionally less time
(compared to the slower one), than would be the case on a windless day,
the reason being its now proportionally shorter hypotenuse.
Assuming the projectiles' characteristics do not change, an increasing
wind will cause the difference in their average velocities to skyrocket
alarmingly, this being a very good reason to use a higher velocity
cartridge, assuming that won't cause other problems, when shooting
outdoors since the wind speed is not something you can control.
Utilizing a low-velociy round at range on a very windy day could force
you to aim into the wind at something ridiculously close to
ninety-degrees in extreme cases. [1] Even if properly calculated the
angle could cause some consternation among upwind spectators. Okay, I
admit things are much more likely to arrive at that sad point in archery
than in gunnery but just by way of illustration...
The calculation of an exact speed can get tricky because velocity in an
atmosphere is not a constant but given the large gap between typical
bullet speed and that of the wind you can usually safely ignore the
steady deceleration and still get quite a usefully accurate result.
It is somewhat similar to the reason the faster of two bullets, fired
parallel to the ground, will travel farther even though their flight
time will be identical.
# Black Powder Silhouette shooters typically shoot rams at 500 meters (547 yards)
# and can knock 10 for 10, where the trajectory is on the order of 17 feet high.
Yes, I can see that being done under such artificial conditions.
# So there! Once you sight in your hight trajectdory at 200 yards, there is no
# need to do it every time you go to the range.
Right, as long as you know your target is approximately two-hundred
yards away.
[1] Of course a rapidly decreasing average velocity also means you must
keep raising the barrel.
-- AK
--
Please reply to the newsgroup. That is why it exists.
-----------------------------------------------------------
MTNMANN
Your interpretation of the laws of physics where the faster the bullet gets
there, the less effect the wind has on drift DOES NOT apply in this case.
Check any ballistics program and you will see this. The following calculations
show:
38-55 Winchester, 240 grain, Lyman bullet #375248, wind at 3 or 9 o'clock.
MV 200 yd wind drift
1000 fps 18.2
1100 fps 21.4
1200 fps 25.1
1300 fps 27
1400 fps 27.5
1500 fps 27
1600 fps 25.4
As you can see the wind drift increases to a point and then flattens out, which
probably relates to the ballistic coefficient changing when it is above or
below Mach 1.
ACCURACY
If you think shooting rams at 500 meters is an artificial condition, you should
try it.
TRAJECTORY
Trajectory is a function of velocity. All things equal, except velocity, it
has no effect on accuracy.
mtnmann
Keith Whaley
moment, what speed is the CROSSWIND in this exercise? You show most
everything but the wind velocity!
On the other hand, let's NOT ignore the other thing bothering me!
You're telling me that given a constant cross-wind, a faster bullet,
which is exposed to this side force for less overall time, will drift
more than a slower bullet, which is exposed MORE time?
How is that, pray tell?
keith whaley
MTNMANN wrote:
#
# WIND:
# Your interpretation of the laws of physics where the faster the bullet gets
# there, the less effect the wind has on drift DOES NOT apply in this case.
# Check any ballistics program and you will see this. The following calculations
# show:
# 38-55 Winchester, 240 grain, Lyman bullet #375248, wind at 3 or 9 o'clock.
# MV 200 yd wind drift
# 1000 fps 18.2
# 1100 fps 21.4
# 1200 fps 25.1
# 1300 fps 27
# 1400 fps 27.5
# 1500 fps 27
# 1600 fps 25.4
#
# As you can see the wind drift increases to a point and then flattens out, which
# probably relates to the ballistic coefficient changing when it is above or
# below Mach 1.
#
# ACCURACY
# If you think shooting rams at 500 meters is an artificial condition, you should
# try it.
#
# TRAJECTORY
# Trajectory is a function of velocity. All things equal, except velocity, it
# has no effect on accuracy.
#
# mtnmann
MTNMANN
The problem is that I am talking about a 38-55 bullet at velocities between
1000 and 1400 fps, and you guys are thinking 30-06 at 3000 fps.
For example:
30-06 Spfld, 180 gr Remington Bronze, crosswind of 30 mph, muzzle velocities as
shown, 200 yard drift.
MV 200 yd V Drift, @200 yds
1000 930 13.6
1100 1002 16.0
1200 1067 18.6
1300 1133 19.7
1400 1206 20.0 (200 yd. Mach 1 Threshold)
1500 1284 19.7
2000 14.3
2500 10.3
3000 7.9
So you can see that even a 30-06 at lower velocities, the wind drift INCREASES
with velocity. At a point where at muzzle velocity is 1400 fps, the 200 yard
velocity is 1206 fps, which is about Mach 1. Above MV of 1400 the reverse
happens and drift decreases as velocity increases.
You guys are trying to reason that the bullet going faster is exposed to the
wind for less time, and I am telling you that there is more to consider than
just the time at these lower velocities.
The ballistic coefficient is different at speeds below the speed of sound, than
speeds above the speed of sound, (Mach 1)
I didn't write the laws of physics, I just obey them.
You guys don't have to believe me, just go try your own ballistics program and
see for yourself.
Black powder silhouette shooters know that this is a fact because their
shooting is done at velocities between 1000 fps and 1400fps.
Mtnmann
BJamesjr
#has no effect on accuracy.
#
Variation in velocity has an affect on trajectory and thus an affect on point
of impact at extreme ranges. I don't know if it has more affect on low
velocity or high velocity rounds though. I remember reading that a good AR
should group in a 4" wide X 6" high rectangle at 600 yards. Variation in
velocity must be the reason that it wouldn't group into a 4" diameter circle.
j del col
# believe) that is chambered in 38-55. This is a caliber I have never heard
# of before, and I suppose finding new ammunition for this caliber would be
# pretty tough. I also have two old boxes of ammo that came with the rifle.
# Does anyone out there have any info on how this caliber compares to
# something more modern? I would like to at least take it to the range and
# shoot some targets to see how it shoots. Any info is appreciated
#
# Thanks in advance
# Rob L
Factory ammo is made by Winchester. Some modern .38-55 rifles
are being sold these days. They are more strongly built than the oldtimers.
Old .38-55 rifles should be used only with blackpowder or the mild
factory loads Winchester sells or mild smokeless handloads.
In addition, they are probably better off with lead bullets than
with jacketed rounds. The steel in those
old barrels isn't as tough as modern steel.
One word of caution---NEVER-- try using .375 Winchester rounds in your rifle.
They will fit, but they will also ruin your gun and possibly injure you.
The .375 Win. is a modern round that operates at much higher pressure
than the .38-55.
J. Del Col
Adam Kippes
# Your interpretation of the laws of physics where the faster the bullet gets
# there, the less effect the wind has on drift DOES NOT apply in this case.
Of course it does. Or would you care to explain why the natural laws
contain an exemption just for you?
Look, the reasoning is *very* simple, you don't need to do the math,
which I know you can't do, unless you want an exact answer. All
projectiles will be "pushed" downwind at the same rate, i.e., linear
distance per unit of time, e.g., so many feet per second; therefore, the
less time spent enroute, the less the drift. Period. You can calculate
the exact distance that must be covered give the necessary angle, the
projectiles resulting velocity relative to the ground, etc., but that's
just fine tuning it, keeping in mind that bullets don't differ much.
That's why I threw in this part:
"It is somewhat similar to the reason the faster of two bullets, fired
parallel to the ground, will travel farther even though their flight
time will be identical."
You do understand the above, don't you?
# ACCURACY
# If you think shooting rams at 500 meters is an artificial condition, you should
# try it.
As you define it? It's artificial as all get-out. But what's wrong with
that? All I meant was that taking your low-velocity cartridge into the
field would be an exercise in futility, at all but the shortest ranges,
because the trajectory would require you know both the range and the
size of the target, more or less exactly, to have any chance of hitting.
# TRAJECTORY
# Trajectory is a function of velocity.
What does that mean?
# All things equal, except velocity, it has no effect on accuracy.
Nonsense. You're snaking all over the place and making no sense.
-- AK
--
Please reply to the newsgroup. That is why it exists.
-----------------------------------------------------------
Adam Kippes
# You guys are trying to reason that the bullet going faster is exposed to the
# wind for less time, and I am telling you that there is more to consider than
# just the time at these lower velocities.
Such as what and why is it different at lower velocities? I've given you
my explanation so try reciprocating.
# The ballistic coefficient is different at speeds below the speed of sound, than
# speeds above the speed of sound, (Mach 1)
That's meaningless, as in - different how? Are you referring to a change
in a bullet's bc during its flight? You are constantly most imprecise, I
suspect for a very good reason.
What does the ballistic coefficient have to do with wind drift?
Retention of velocity isn't involved here.
# I didn't write the laws of physics, I just obey them.
No, you don't, quite the opposite. What physical laws are you obeying
here, for example? As opposed to those you are violating.
# You guys don't have to believe me, just go try your own ballistics program and
# see for yourself.
What would that prove?!? *My* ballistic program shows the slower bullet
doubling its velocity when the wind speed exceeds three miles per hour
but remains below ten miles per hour. Except on Sundays. <g>
# Black powder silhouette shooters know that this is a fact
belief != knowledge
-- AK
--
Please reply to the newsgroup. That is why it exists.
-----------------------------------------------------------
Norman Johnson
#So you can see that even a 30-06 at lower velocities, the wind drift INCREASES
#with velocity. At a point where at muzzle velocity is 1400 fps, the 200 yard
#velocity is 1206 fps, which is about Mach 1. Above MV of 1400 the reverse
#happens and drift decreases as velocity increases.
#
#You guys are trying to reason that the bullet going faster is exposed to the
#wind for less time, and I am telling you that there is more to consider than
#just the time at these lower velocities.
You are quite correct.
The subject of (non-linear) bullet drift was written about
at least as far back as 1978 (see The Fouling Shot, page 13-42).
Drift peaks at about 1300-1400 fps then decreases. Be sure to see
the drift equation at the end of this post.
The subject is more complex than most of us might expect. I
have excerpted the following under the topic "BALLISTICS:
EXTERIOR" from The Fouling Shot Index. The second article
listed below will really open your eyes and hold some surprises
for most.
FORM FACTORS OF TYPICAL SHAPES OF CAST BULLETS
DAVIS & SEARS & HARRIS 12-02, 20
EXTERIOR BALLISTICS, CONTINUED (this is continued from the above
even tho the article name is different)
DAVIS, W.C. 13-10, 42, GRAPH, TABLE
DOES A STEADY WIND PERMIT BETTER SCORES THAN A DEAD QUIET?
MUSSELMAN, S.F. 36-16, 66
CORRECTION AND COMMENTS ON DRAG
HARRISON, E.H. 41-17, 12
EFFECT OF VELOCITY VARIATION ON DROP OF TYPICAL BULLET
DAVIS, W.C. 41-19, 20, TABLE
WIND EFFECTS ON GROUPS
BARNISKIS, A.E. 42-16, 58 PICTURES, TABLE
TWIST FOR HEAVY .22'S
HARRIS, C.E. 48-03 15 Q&A
REFERENCES ON RIFLING TWIST (GREENHILL'S RULE)
HARRIS, C.E. 48-05, 19 Q&A
BULLET DROP CHRONOGRAPH
HULT, C.G. 48-08 10
ON BULLET STABILITY
BARNISKIS, A.E. 50-08, 74 ANDY'S ANGLE
COMPARING CAST BULLET CALIBERS
DAVIS, W.C. 50-28, 37 TABLE
MORE ABOUT GREENHILL'S FORMULA
DAVIS, W.C. 52-02, 20 Q&A
GREENHILL MADE EASY
LATHAM, GLENN R. 53-38, 20 TABLE
BALLISTIC COEFFICIENTS OF CAST BULLETS
DAVIS, W.C. 54-02, 24 Q&A, CALCULATIONS
UNCLE HERMANN HAS A
QUESTION
63-23, 20 DRAWING
IMPOSSIBLE BECOMES REAL
KELLY, PACO 65-05, 30 PACO'S POINTERS
THE .577/450 FARQUAHRSON WAS FUN
MARSHALL, JR., FRANK 73-05, 46 SPEAKING FRANKLY
TIPPING BULLETS
LATHAM, GLENN R. 81-03, 13 Q&A
*********************************************
Subject: Drift formula
Range
Flight Time - -------------------- = Lag Time
Muzzle Velocity
Lag Time x Cross Wind Velocity = Deflection
where:
Time is in seconds,
Range is in feet,
Muzzle velocity is in feet per second,
Lag Time is in seconds
Cross Wind Velocity is in inches per second (10 mph=176" per second)
Deflection is in inches
Try it yourself.
God Bless!
Norm
Wes Jones
Adam Kippes wrote:
#
# In <ahe9pd$m2h$1...@grapevine.wam.umd.edu>, MTNMANN wrote:
#
# # Your interpretation of the laws of physics where the faster the bullet gets
# # there, the less effect the wind has on drift DOES NOT apply in this case.
#
# Of course it does. Or would you care to explain why the natural laws
# contain an exemption just for you?
#
# Look, the reasoning is *very* simple, you don't need to do the math,
# which I know you can't do, unless you want an exact answer. All
# projectiles will be "pushed" downwind at the same rate, i.e., linear
# distance per unit of time, e.g., so many feet per second; therefore, the
# less time spent enroute, the less the drift. Period. You can calculate
# the exact distance that must be covered give the necessary angle, the
# projectiles resulting velocity relative to the ground, etc., but that's
# just fine tuning it, keeping in mind that bullets don't differ much.
Except it isn't as simple as that. A heavier bullet will have less wind
drift for an equal amount of flight time than a light bullet. Reason
being is that as a lead object gains mass it doesn't gain in sectional
area as fast. There is a higher surface area to weight ratio in a
lighter bullet than in a heavier bullet of same diameter. So as I
understand it, wind drift is determined by the mass of the bullet,
x-sectional area exposed to the wind, time of exposure and wind velocity
.
The heavier bullet is accelerated away from it's original line of travel
at a slower rate than the lighter bullet, everything else being equal,
due to the lighter bullet's greater x-sectional area per unit of mass.
Best, wes
Keith Whaley
Now you did it!
Now I have to see how many sources I can find to read, just to prove
that the physics of wind drift allow non-sensible ideas to hold forth...
Sighhh.
I'm not done with you yet. I'll actually look some of them up, and
study your formula(ae.)
I've saved this message to my desktop for further review ;^)
Keith Whaley - gunsmith/owner
WHALEY's Gunsmithing
Westchester, CA
Norman Johnson wrote:
> ...
Adam Kippes
# You are quite correct.
Not that I can see, but then I don't see much here. <g>
# The subject of (non-linear) bullet drift
Non-linear?
# was written about at least as far back as 1978 (see The Fouling Shot, page 13-42).
That doesn't *prove* anything. I mean, heck, Evan Marshall and Ed Sanow
are always writing about their ideas, too, but they are still full of
whatever you wish to call it. Not to mention astrologers, alien
abductees, scientologists, etc.; even von Daniken might make a comeback
one of these days.
# Drift peaks at about 1300-1400 fps then decreases. Be sure to see
# the drift equation at the end of this post.
Now you are contradicting him. Of course he contradicts himself, too.
But all of that is as nothing compared to your self-contradiction.
# The subject is more complex than most of us might expect.
Why? What is the explanation for this state of affairs? Please, I'm not
going to track down a bunch of gun rag articles which are almost
certainly worthless, anyway. Just tell me the reason, that being
something neither of you seem able to do at all. Do any of these people
go into that? If so, just an excerpt would be nice. Thank you.
# Subject: Drift formula
# Range
# Flight Time - -------------------- = Lag Time
# Muzzle Velocity
# Lag Time x Cross Wind Velocity = Deflection
Very pretty, but I thought you said "more complex". <g>
But anyway, what is the rationale behind this laughable excuse for a
mathematical formula? By the way, how do you determine flight time
unless you know the drift?!?
Also, deflection is usually expressed as an angle, as an aid to aiming,
if for no other reason. Not that it really matters much, but perhaps
"Drift" would have been the better term here.
# Try it yourself.
Try *what* myself? It's worthless garbage - and I'm being polite. Even
funnier, it doesn't support your claim in the least; just the opposite!
Look, all R/MV does is express the flight time, assuming the velocity is
a constant, i.e., testing is taking place in a vacuum, and is utterly
worthless for any and all purposes; perhaps that is why it plays no
sensible part in your formula. You then subtract that number from the
assumed - but in truth, unknown - flight time. Finally, you multiply
that difference by the wind speed. This is the kind of crap that should
embarrass a fourth-grader; it certainly would have shamed me, not to
mention my teachers, when I was in fourth grade and devising far better
formulae than that for all sorts of purposes. As were some of my
friends, this kind of stuff being fun for some of us.
Oh, yeah, just multiply FT by you-know-what, for a close approximation
of the real answer. Of course, before you can do that you must *know*
the flight time. Bit of a problem there, but what the heck, some
extrapolation should bring you close enough.
So why are you expressing the wind speed and drift in inches(/s) instead
of the more customary feet(/)? And, having done that, why is the range
and muzzle velocity then measured in the reverse? That is very uncool
and just begging for trouble. But try this:
R = 500 yds. (1500') and CWV is 30 mph (44 f/s)in both cases. We will
also assume, just for starters, that the bullets have the same bc, that
is, the ratio of their flight times should equal the ratio of their R/MV
figures. Or, if you prefer, they will shed velocity at the same rate,
expressed as a percentage.
a) MV = 1000
b) MV = 1500
Let's say they average 5/6ths (.833MV) of their initial velocity over
the range; bullet a will arrive in 1.8 seconds and bullet b in 1.2
seconds. So bullet a will drift 13.2 feet while bullet b, to no one's
surprise, will drift only two-thirds as far or 8.8 feet; the real
answers would be 79.2' and 52.8', always assuming we can trust the
stipulated flight times. The only way your claim will work is if, within
the narrow range you have chosen, slower bullets arrive proportionally
sooner than the faster ones. In other words, you seem to be making the
completely unwarranted assumption that slower bullets, simply by virtue
of being slower, have a much superior ballistic coefficient *and* then
only within a most narrow range of velocities; that is not so.
[In the example, if bullet b takes 1.2 seconds FT (not unreasonable),
then bullet a must take no more than 1.7 seconds - else how could they
have the same drift (.2 x LT)? It must have averaged at least .882 of MV
compared to bullet b's .833MV. And it would have to improve on that
performance to actually experience *less* drift.]
The real answers (AAS = actual average speed, relative to the earth):
a) 832.171 f/s AAS; FT = 1.803"; deflection = 3.027 degrees
b) 1249.225 f/s AAS; FT = 1.201"; deflection = 2.017 degrees
Note that the ratio of their AAS (b:a) is 1.501164 as compared to
exactly 1.5 for their MV; this is due to the *greater* drift experienced
by bullet a. You must also aim just over an extra degree upwind.
I realize anything is possible in science - look what happened to
Newtonian mechanics - but you are going to have to do much better than
this to convince me, at least, of your claim. That is, you will need one
heck of a lot more than this sad, sorry, silly "formula".
-- AK
P.S. Are you sure Greenhill isn't an earlier version of Fuller? Anyway,
you should get your nose out of the gun rags. But please post the
requested explanation in any case.
--
Please reply to the newsgroup. That is why it exists.
-----------------------------------------------------------
MTNMANN
mtnmann
MTNMANN
#in a bullet's bc during its flight? You are constantly most imprecise, I
#suspect for a very good reason.
Yes! If you understand the meaning of "ballistic coefficient".
Ballistic Coefficient depends on the speed of the bullet, the drag of the air
(a function of temperature/density), and the shape of the bullet.
The drag can change by just passing through from a mass of hot air to a mass of
cold air. And by passing from a speed above Mach 1 to speeds below Mach 1 IN
FLIGHT!
You should try the math.
Adam Kippes
# I'm not done with you yet. I'll actually look some of them up, and
# study your formula(ae.)
Three seconds with the "formula" will do the trick. <g>
-- AK
--
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-----------------------------------------------------------
Doug T
Armory, 405 gr 45-70 cartridge fired at 1365 fps @ 1000yds traveling at
536 fps vs 500 gr same cartridge 1315 fps at muzzle and 711 fps @ 1000
yds. unfortunately the exact time of flight isn't given and must be
worked out using the two velocities and an assumption of constant decay
in velocity probably will be made. BTW Aberdeen gives the M1 30 cal 172
gr fired at 2700 fps arrived at 1000 yds 1.608 seconds later @ 1275 fps.
Doug T
Ken Marsh
#In <ahgsk1$fji$1...@grapevine.wam.umd.edu>, MTNMANN wrote:
## The ballistic coefficient is different at speeds below the speed of
##sound, than speeds above the speed of sound, (Mach 1)
Adam Kippes <adam....@pobox.com> wrote:
#That's meaningless, as in - different how? Are you referring to a change
#in a bullet's bc during its flight? You are constantly most imprecise, I
#suspect for a very good reason.
Sierra lists different ballistic coefficients for different velocity
ranges. So do some other sources. Call their 800 number and ask why.
All ballistic coefficients are just a comparison of your test projectile
versus a standard projectile. Most BC systems are based on some fairly
old subsonic or barely supersonic testing. BC's are not a physical law!
They are a convenient shorthand for trying to map one trajectory against
another. It is no surprise that at extremes, this mapping sometimes
falls apart.
#What does the ballistic coefficient have to do with wind drift?
Oh, so much! It has long been (scientifically, reproducably) noted that
projectiles that decellerate quickly have MUCH MORE wind drift than
projectiles that don't. In some cases this factor can even predominate
over time of flight! All MODERN wind drift calculations consider this-
take a look. This is not a debatable matter of some people's
observations. Decelleration affect on wind drift is an observable fact;
the only question is, what is the best way to calculate it?
Ken.
--
-------------------------------------------------------------------------
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Adam Kippes
# Here are a couple of numbers for you to try out
There is not enough information to do anything with the first two but we
can calculate this one, using the equation offered:
# BTW Aberdeen gives the M1 30 cal 172
# gr fired at 2700 fps arrived at 1000 yds 1.608 seconds later @ 1275 fps.
That's a pretty good ballistic coefficient for the old .30-06. Then
again, the military ball round had a decent sectional density and a very
pointy nose.
The figure was calculated for still air, I assume. I am also assuming
Mr. Johnson's Flight Time refers to the same measurement because I don't
know what else it could possibly mean.
I've rearranged the equation ever so obviously in order to make it look
a bit more professorial; it doesn't affect anything.
LT = 1.608 - (3000 / 2700)
LT = 1.608 - 1.111
LT = .497
and therefore D = 21.868', assuming a 44 f/s cross wind at exactly
ninety degrees.
True drift = 70.752'
True average velocity = 1865.153 f/s (indicated = 1865.672 f/s)
True flight time = 1.608477" (vs 1.608 indicated)
Required deflection = 1.351 degrees or 81.083 MOA
But remember rounding is being done and see footnote [2], below.
Okay, here is another example and, N.B., everything from here to the end
involves an impersonal "you". Please note that.
a) R = 3000', MV = 3000 f/s, FT = 2" (avg. vel. = 1500 f/s), LT = 1"
b) R = 3000', MV = 600 f/s, FT =6" (avg. vel. = 500 f/s), LT = 1"
Please note that bullet b obviously has one whomping good ballistic
coefficient. But anyway, in both cases the so-called "Deflection" will
be forty-four feet - does that really make *any* sense to you? Do you
really believe that one projectile can spend three times as long in a
given cross wind as another and still have the same drift?!? You must
move to an alternate universe for a projectile to spend six seconds in a
cross wind of 44 f/s and yet drift only forty-four feet, especially if
you are willing to accept the same drift for a bullet spending only
one-third that time in the same cross wind.
Unless maybe there is some explanation that no one has seen fit to post.
Unfortunately, neither Mtnmann nor Mr. Johnson seem willing to do that.
# unfortunately the exact time of flight isn't given and must be
# worked out using the two velocities and an assumption of constant decay
# in velocity probably will be made.
That is but one reason why that equation is a piece of childish junk.
You needn't make any guesses as to the resulting, actual flight time if
you do things properly. True, this will require an understanding of
junior high school math of the pre-geometry/trigonometry variety, but is
that really asking so much of adults? All you need is the wind speed,
and flight time in still air, i.e., in the absence of a wind (not in the
absence of an atmosphere - what *is* that all about?).
You do realize that the variable labeled Lag Time in the equation is
nothing but the increase in flight time due to the presence of
atmospheric drag? Of what possible significance is that figure to
anything but itself? Sure, knowing it might be interesting but how does
it have anything -anything at all -to do with wind drift?
I don't know what ballistics program Mtnmann is using but I checked
several other such things that are obviously using the given equation;
they all show exactly what one would expect, i.e., drift is exactly
proportional to flight time. Always. The resulting figures are worthless
but at least they reflect the basic concept. Why Mr. Johnson thinks his
equation will show anything else, for example, a peak drift at 1300-1400
f/s is beyond me; perhaps he's never actually used the equation. Or
perhaps he is doing something I warned about earlier, namely making the
completely unwarranted assumption that slower bullets automatically lose
velocity more slowly (as a percentage) - much more slowly - simply by
virtue of their being slower. That is not at all true.
But that still wouldn't explain the "Drift peaks at about 1300-1400 fps
then decreases" claim. What does muzzle velocity have to do with drift?
Like almost everything else published for gun owners (or users) this is
worthless garbage, just like the idea of kinetic energy meaning
something in terms of "stopping power" [1], the even more laughable
calculation of recoil "energy", the idea of one-shot stopping power,
etc.
So what is all of this interest shown in the weight, caliber, etc. of
the bullets? That has nothing to do with wind drift; all you need is
flight time on a windless day and the wind speed. That will give you the
drift; in conjunction with that, or simply by working backwards, you can
calculate the necessary angle of fire (deflection) and, for that matter,
the true flight time and, of course, the true average velocity.
For those averse to geometry, never mind trigonometry, (sine,
hypotenuse, and right angle will make things easier but I realize some
people just don't like such things) here is another method for
determining the deflection [2] (T = true and I = indicated):
R = 1500'
Iav = 1000 f/s, so obviously Ift, i.e., R / Iav, = 1.5"
Wv = 44 f/s (30 mph)
therefore:
Wd = Ift * Wv or 66'
and, should you wish to know:
Tav = Sqr( Iav^2 - Wv^2 ) or 999.032 f/s
Tft = R / Tav = 1.501454"
D = Sin( Wv / Iav, -1) or 2.522 degrees
Now, convert the wind drift to inches (x12): 792"
Divide by 1.047 (one MOA at 300'): 756.447
Divide by 5 (R / 300) for the minutes-of-angle: 151.289
Divide by 60 to find the necessary deflection, in degrees: 2.521 (this
is what rounding does to you)
If you really need more precision than this you will have to calculate
the base MOA to a greater number of decimal places, e.g., 1.047198.
An example of how little things add up... if you round the above
deflection (2.522) to 2.5 (or 150 MOA), your bullet will end up about
6.60" downwind of the intended target; were you to use 2.55 (or 153
MOA), you would hit about 9.11" upwind. As another example, if you use
1.047" for a MOA at 100 yds., you won't get those exact figures. <g>
[1] That is, actually causing noticeable harm to any living creature. Do
*any* of its fans know what [kinetic] energy is, how it is acquired, how
it performs work, and, especially, just how little work is performed by
one foot-pound? Do they even know what "foot-pound" means? And why do
they keep calling it just "energy", "muzzle energy", "impact energy, and
so on? This kind of information can be learned very quickly and very
easily by anyone who cares to make the effort.
[2] Technically, using a differential equation might give you more
accuracy. Whether said precision will be usable is another matter; as
shown by the Tav and Tft figures, you might need eight or more decimal
places to see the difference... but it *will* be there, at some point.
Don't even ask what happens if the wind is varying wildly instead of
conveniently constant, as in, "What do you think 'Kentucky windage'
means, anyway?" <g>
-- AK
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-----------------------------------------------------------
Del
If you have sorted through all this bickering non hunter bullsh-t,
you have a nice gun. If you hunt medium game, and can stick a bullet
in the right place, you will have meat with your potatoes every time.
If you dont hunt, its is fun just to shoot targets with a friend. If
you need a G-dd-mn slide ruler, your in the wrong hobby.
Del
Keith Whaley
Keith Whaley - gunsmith/owner
WHALEY's Gunsmithing
Mar Vista, CA
Del wrote:
#
# # Dear RobL:
# If you have sorted through all this bickering non hunter bullsh-t,
# you have a nice gun. If you hunt medium game, and can stick a bullet
# in the right place, you will have meat with your potatoes every time.
# If you dont hunt, its is fun just to shoot targets with a friend. If
# you need a G-dd-mn slide ruler, your in the wrong hobby.
# Del