45/70 calculations WC860
Clark Magnuson
[surplus $2~3/ lb) and it will fill the case for a reduced load.
This site shows WC860 to be like H-870
http://web.mountain.net/~kneiper/surpow.htm
This site shows WC860 to be like H-870 or AA8700
http://www.gibrass.com/gunpowder.html
This site shows those powders to be the slowest
http://www.cctrap.com/~varmint/pburn.htm
as well as this
http://www.reloadammo.com/burnrate.htm
The Speer #12 Reloading Manual shows loads to keep the 45/70 below
21,000 c.u.p. for a conservative derating [Trapdoor]. One such load is a
compressed load of 53 gr of H4895 behind a 400 gr jacketed bullet.
The same manual shows a 270 Weatherby magnum using IMR4895 [equivalent
to the H4895] as max pressure at 64 grains behind a 100 grain bullet and
82 gr compressed of H870 as max behind a 150 grain Weatherby mag 270.
#From this manual we may infer that 82 gr of H-870 causes much less
pressure than 64 gr of IMR4895.
Therefore we may conclude that one could use as a starting point 53 gr
of WC860 behind a 400 gr jacketed bullet in a trapdoor Springfield 45/70
[the lowest pressure 45/70]
The relationship between c.u.p. and psi is shown in the table in
Alliant's site
http://www.AlliantPowder.com/
Click reloading data
Click download
Click open
Click OK
go to page 56
You will see that c.u.p is equal to or to 20% less than psi
I bought a 45/70 today. It is a Handi rifle [break action]. I wanted to
do some calculation to see if it could be loaded to .458 Win Mag like
pressures. The hinge pin is 3/8" in diameter and the case of the
cartridge is .5" in diameter. The force = (pressure) (area) = [50,000
psi][(.5)(.5)(Pi)/4] = 9817 pounds
The shear stress = force/ area = 9817 lb/ [[(3/8)(3/8)(Pi)/4](2)]=
44,444 psi {the (2) comes from the fact the pin will have to shear in
two places}
Heat treated 4340 steel has a shear yield of about 78,000 psi.
The chamber has an O.D.=1.112" and an I.D.=.5"
The tensile stress on a chamber = (pressure)(inside diameter)/ twice the
thickness of the walls = (50k psi)(.5)/[1.112 - .5] = 40k psi tensile
stress
Heat treated 4340 steel tension yields at 230k psi.
Clark
----------------------------------------------------------------------
Please find out about rec.guns at http://doubletap.cs.umd.edu/rec.guns
flimflam
what that kind of load will do to his shoulder ? Handi Rifles are not known
to be real "user friendly". Glad it's him, and not me :-)
Shoot on,
Flimflam
A-1 Pawn & Jewelry
1925 S.E.Hwy 19
Crystal River, Florida, 34429
352-795-2777
fax# 352-795-2093
flim...@xtalwind.net
boyd
> ...
WC860 is just too slow burning to work well in a .45-70. The large
surface area of the bullet and the limited case volume never allow the
powder to burn adequately. I have NOT tried these loads, but I just ran
calculations and concluded you would get a cartridge somewhat resembling
a black powder load using 60 grains of WC860 with 405 grain bullets
(jacketed). Thats a 106% compressed load if the seating depth is .53"
. The problem is that only 1/4 of the powder gets burned in a 24"
barrel and you will have a huge muzzle blast when the other 75 percent
burns outside of the barrel! The pressure is only about 13,000 psi
peak and the muzzle velocity only about 1000 fps. Sounds like a fun
load for shooting silhouettes with a T/C pistol but it would probably
get you thrown off the range. :-)
I'm not at all recommending you try the above load or any other using
WC860 in a .45-70 case and I wouldn't even think of using a reduced load
under around 50 grains for fear of detonation. That's an 89 percent
fill. Only 20 percent of the powder burns with pressure around 7000 psi
and the velocity would be about 875 fps. You are on very thin ice using
such a radically mismatched powder for your gun. WC860 is a common
spherical powder used in the .50 BMG cartridge where it works quite well
using about 230 grains to push a 650 grain bullet out of a 44 inch
barrel.
--
Lou Boyd
FCSA-GOA-NRA-JPFO
Article II: A well regulated Militia, being necessary to the security of
a free State, the right of the people to keep and bear Arms, shall not
be infringed.
Doug Owen
Clark Magnuson wrote:
#
# The reason for wanting to use WC860 in a 45/70 is because it is so cheap
# [surplus $2~3/ lb) and it will fill the case for a reduced load.
# This site shows WC860 to be like H-870
# http://web.mountain.net/~kneiper/surpow.htm
# This site shows WC860 to be like H-870 or AA8700
# http://www.gibrass.com/gunpowder.html
# This site shows those powders to be the slowest
# http://www.cctrap.com/~varmint/pburn.htm
# as well as this
# http://www.reloadammo.com/burnrate.htm
There's a reason it's so cheap, it's not all that suitable for most
rounds. Hard as it may be to deal with, some other folks have looked at
the issue before. Powder that cheap, if it was useful, would not be
that cheap.....
#
# The Speer #12 Reloading Manual shows loads to keep the 45/70 below
# 21,000 c.u.p. for a conservative derating [Trapdoor]. One such load is a
# compressed load of 53 gr of H4895 behind a 400 gr jacketed bullet.
# The same manual shows a 270 Weatherby magnum using IMR4895 [equivalent
# to the H4895] as max pressure at 64 grains behind a 100 grain bullet and
# 82 gr compressed of H870 as max behind a 150 grain Weatherby mag 270.
# #From this manual we may infer that 82 gr of H-870 causes much less
# pressure than 64 gr of IMR4895.
# Therefore we may conclude that one could use as a starting point 53 gr
# of WC860 behind a 400 gr jacketed bullet in a trapdoor Springfield 45/70
# [the lowest pressure 45/70]
#
This, at first pass, seems full of some very dangerous (and wrong)
assumptions. First off, peak pressure is a function of the amount of
gas evolved (a fixed amount dependant on how much has burned and *how
big the chamber and bore are* at that point in time). Slow powders burn
slower, waiting for a bigger volume. Light bullets get out faster,
giving a bigger volume. You absolutely cannot cross one to the other,
even in much bigger guns than small arms. That's why ballistic labs
make such good money testing.
# The relationship between c.u.p. and psi is shown in the table in
# Alliant's site
# http://www.AlliantPowder.com/
# Click reloading data
# Click download
# Click open
# Click OK
# go to page 56
# You will see that c.u.p is equal to or to 20% less than psi
This is true at one point in some cartridges. Look at .30-30 or 7X57 in
that same table.....it's only !0%, right? You could have just blown up
someone's gun with your advice.... .223 would have put some fool in
deep s### if he'd have taken your advice, closer to 5%.
#
# I bought a 45/70 today. It is a Handi rifle [break action]. I wanted to
# do some calculation to see if it could be loaded to .458 Win Mag like
# pressures. The hinge pin is 3/8" in diameter and the case of the
# cartridge is .5" in diameter. The force = (pressure) (area) = [50,000
# psi][(.5)(.5)(Pi)/4] = 9817 pounds
# The shear stress = force/ area = 9817 lb/ [[(3/8)(3/8)(Pi)/4](2)]=
# 44,444 psi {the (2) comes from the fact the pin will have to shear in
# two places}
# Heat treated 4340 steel has a shear yield of about 78,000 psi.
#
# The chamber has an O.D.=1.112" and an I.D.=.5"
# The tensile stress on a chamber = (pressure)(inside diameter)/ twice the
# thickness of the walls = (50k psi)(.5)/[1.112 - .5] = 40k psi tensile
# stress
# Heat treated 4340 steel tension yields at 230k psi.
This I don't follow, although given your accuracy with what I know to be
prudent, I have some doubts. For sure if the maker thought a .458 Win
Mag chambering was safe it'd be in the catalog.
As a first thought, what's the load on the locking surfaces?
Sounds like you have a fairly healthy questioning of what's going on
going for you, hope you have enough respect for traditional advice to
keep yer skin intact until you do your homework. For the time being, I
suggest at least the string and spare tire test procedure....best make
it a spare you don't need...
Doug Owen
Wes Derrick
----------
In article <7s2rsu$g9e$1...@xring.cs.umd.edu>, Clark Magnuson
<cmag...@home.com> wrote:
> ...
Clark, maybe the mathmatics you should be practicing are those for
calculating annuities
and life insurance rates. Really, from your calculations you seem to have
arrived at the
conclusion that it would be okay to load a .45-70 up to .458 pressures. (In
a handi-rifle
no less). The short answer is no. The long answer is no, don't be stupid.
While your calculations work on paper, they neglect a lot of stuff that's
going to happen.
For one, you probably don't have to shear the pin in one place, once one
shears there
is almost certainly enough flexibility for something to bend/flex enough for
the action to
open up (or at least apply unequal stress which will break the action open).
If by any chance you won't take any kind of advice about not overloading the
handi-rifle,
at least stand back so that when it does explode you don't get hurt.
Again, don't do it.
Wes Derrick
> ...
fl...@alaska.net
# ...The Speer #12 Reloading Manual shows loads to keep the 45/70 below
# 21,000 c.u.p. for a conservative derating [Trapdoor]. One such load is a
# compressed load of 53 gr of H4895 behind a 400 gr jacketed bullet....
The use of slow burning powders in the .45-70 has been going on for
decades. H4831 was the first one I tried, and compressed loads were
safly low pressure with bullets up to 450 grains. Lighter bullets
didn't shot well due to poor burning. Fouling was bad with this
powder, but accuracy was excellent with 350 grain bullets and up.
WC860 will probably work, especially since Accurate shows compressed
loads of AA8700 as giving .45-70 pressures of under 20,000 psi. The
comparisons with the same powders in the .45-70 and the .270 Weatherby
could be dangerous, since the pressures are WAY different, and powders
can burn differently at vastly different pressure levels.
# The relationship between c.u.p. and psi is shown in the table in
# Alliant's site....You will see that c.u.p is equal to or to 20% less than psi...
There is NO general rule of thumb for comparing cup and psi - they are
two very different things. That's why there is such a wide varience
between them - from zero to over 25 percent.
# I bought a 45/70 today. It is a Handi rifle [break action]. I wanted to
# do some calculation to see if it could be loaded to .458 Win Mag like
# pressures. The hinge pin is 3/8" in diameter and the case of the
# cartridge is .5" in diameter. The force = (pressure) (area) = [50,000
# psi][(.5)(.5)(Pi)/4] = 9817 pounds.....
Interesting calculations, but flawed. The barrel hoop stresses will
not be the limiting factor ( as it isn't in most rifles ), the action
strength will be. Because the hinge pin is well below the watertable,
a direct calculation using it's yield strength will not give the true
action strength due to differing force vectors. Lots of potentially
dangerous assumptions here....
The maximum stress the action will experience will be the force
applied by the chamber pressure on the maximum INSIDE diameter of the
case. In the .45-70 this is ca .460". To do a better numbers game on
the Handirifle ( a great little rifle BTW ), base the action strength
on the hottest loading it is currently chambered for. This is
probably the .270 WCF ( 65,000 psi ). The inside area of a .270 case
is about .125 sq in, so with a max chamber pressure of 65,000 psi the
force on the action is ca. 8100 lbs. For the .45-70 to equal this
force, it would have to generate just 49,000 psi.
Now, how can one calculate when a .45-70 load will generate 49,000
psi, with no load data to go by? Speer shows loads up to 35,000 cup,
and Hornady shows data to 50,000 cup; but we know that cup and psi are
not the same. What does one do?
Even the above calculations are liable to be misleading. Case shape
and design play a role in the force transfered to the action. The
time/pressure curve of a cartridge/powder/bullet combination can also
effect an action's response to stress.
Personally, I believe that the Handirifle is safe up to loads listed
for the M1895 Marlin. It may be safe higher, but I would NOT want to
fire them in my H&R .45-70!! I also own a bolt action .45-70, shoot
very heavy loads in it, and it recoils accordingly; it weighs 10 lbs
with scope, while the HandiRifle weighs a LOT less......
Jay T
Clark Magnuson
Accurate brand powder manual shows a load of 60 gr of 8700 behind a 400
gr 45/70 gives 992 fps out of a 24" barrel. 60 gr behind a 500 gr gives
1033 fps.
2 1/2 cents a shot for powder.
Fasteddie3
Well, except for the minor problem that WC860, probably designed to originally
work in a cannon shell at 40K psi or so, may not be interested in burning in a
very low-pressure environment, and you will have a bunch of unburned powder in
your case and barrel to show for your efforts. If it was just a matter of
stuffing a slow-burning powder into the 45-70 to get low pressures, you should
also see listings in the manuals for 4350, 4831, WMR, and other suchlike. Last
I looked, such loadings were conspicuously absent.
You would probably be better advised to use a fast-burning powder like 4227,
which may cost a lot more per pound, but should also work nicely with loads of
around 20gr. for a target load, burning cleanly, and giving you maybe 300 loads
per pound, which is hardly expensive.
IMHO
Ed Arnold
JerryO
# The reason for wanting to use WC860 in a 45/70 is because it is so
cheap
# [surplus $2~3/ lb) and it will fill the case for a reduced load.
# This site shows WC860 to be like H-870
# I bought a 45/70 today. It is a Handi rifle [break action]. I wanted
to
# do some calculation to see if it could be loaded to .458 Win Mag like
# pressures. The hinge pin is 3/8" in diameter and the case of the
# cartridge is .5" in diameter. The force = (pressure) (area) = [50,000
# The shear stress = force/ area = 9817 lb/ [[(3/8)(3/8)(Pi)/4](2)]=
# 44,444 psi {the (2) comes from the fact the pin will have to shear in
# two places}
# Heat treated 4340 steel has a shear yield of about 78,000 psi.
Question, Is this the steel receiver or the weaker iron one?
In either case I think you have the wrong force on the hinge pin as the
receiver & stock is taking some of the force. Assuming the barrel is
twice as heavy as the receiver, the hinge pin will only need to hold
2/3 of the force.
Also, the case grip on the chamber walls will absorb some of the
thrust, which will reduce the force on the hinge pin.
#
# The chamber has an O.D.=1.112" and an I.D.=.5"
shouldn't we deal with the inside of the case here, ie. .458 inches.
Also the brass will give some support.
# The tensile stress on a chamber = (pressure)(inside diameter)/ twice
the
# thickness of the walls = (50k psi)(.5)/[1.112 - .5] = 40k psi tensile
# stress
# Heat treated 4340 steel tension yields at 230k psi.
# Clark
As the handi-rifle is not offered in an caliber with the magnum case, I
expect something must be marginal with that amount of force. It may be
the latch comes open and it becomes an auto-eject rifle. Certainly the
7mm magnum would be offered if the required safty margin could be
maintained.
However, if you scale to the force (like pressure) of the 30-06 case
(they have offered both 25-06 and .270) you should be in a safe area.
I also am concerned how you know what heat treatment is used in the
rifle. Or that the numbers for stress that you provide are valid for
the shock environment of a rifle as opposed to static testing.
I'm not familiar with WC860, but I have found that some powders are
hard to burn. As the tempreture (as in presure) gets lower, the residue
increases dramaticly. This seems to more of a problem with double base
(ball) powders than the single base stick powders. It has been
suggested that in the worse case a ball powder can smolder until the
coating is gone, then explode. However AA does recommend their 8700
for cast bullet loads, so I expect it to be fine.
Speaking of AA, I recently bought a pound of their AA2460 which I tried
to use in an 8mm mauser. I started with very light loads (37 grains and
185 gr bullets) and worked up to a heavy load (53 grains). It started
incrediblely dirty (entire case black) and became just so-so (neck
smokey) by 48 grains. At 52 and 53 grains burning was inconsistant with
some rounds 300 feet/second slower than average. The faster loads were
enlarging the primer pockets and swelling the case heads which fit with
pattern of the other loads. But the slow rounds were scary
(unexpected). It never did get any cleaner either. I switched to H-
VARGET as IMR-4064 wasn't available in the store I went to. It was much
cleaner (even at light 40 grain loads) and was consistant up to a
compressed charged of 53grains.
And I thoughtI was the only one to do this kind of experimenting !!!
--
JerryO
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
Clark Magnuson
# As a first thought, what's the load on the locking surfaces?
The latch lodges between the receiver and barrel. The contact is .16
x.61". The hinge pin is 16 degrees off the center of barrel measured
from the breech face. The shear force is then [sin (16 degrees)] 9817 lb
= 2706 lb of shear. The shear stresses = F/A = 2706/[[.16][.61]] =
28,000 psi shear stress on latching surface of barrel. The latch itself
sees 28,000 psi of compression.
Clark
Clark Magnuson
# For one, you probably don't have to shear the pin in one place, once one
# shears there
# is almost certainly enough flexibility for something to bend/flex enough for
# the action to
# open up (or at least apply unequal stress which will break the action open).
I showed the rifle to my father. He is the one who explained to me that
there is double shear. I can describe his qualifications:
My father worked at Pacific Car and Foundry [now PACAR] for 40 years. He
got 21 patents and was Chief engineer most of that time. Many of his
ideas were not pursued by Rock Island Arsenal or the number of patents
would be higher.
He got patents on a tank turret balancing system, missile launcher [lost
engineering contract but sold license to winner], tracked artillery [we
have wall hanging pics of two of these] [one uses a over center toggle
system like a Luger], armored personnel carrier [got
the engineering contract but FMC got the production], mobile bridge,
machine gun, two 155mm auto cannons [one with six shot constant recoil][
The proto type for the other was built by Eugene Stoner's little company
at Niagara falls],
the winch which is standard on military vehicles [this winch business is
now a division of PACAR].
There is an expired patent that was developed on PACAR money that Rock
Island Arsenal did not pursue, that my father says is still a valid
concept and should be used where ever a machine gun is in a turret or
should be in a turret. The belt feeds from the back and ejects the
smoke, cases and links out the front. The patent can be viewed at:
http://www.patents.ibm.com/patlist?icnt=US&patent_number=3901123&x=36&y=9
Bruce Rowen
In article <7s5f1i$mkg$1...@xring.cs.umd.edu>, Doug Owen <dko...@home.com> writes:
#
#
#
#There's a reason it's so cheap, it's not all that suitable for most
#rounds. Hard as it may be to deal with, some other folks have looked at
#the issue before. Powder that cheap, if it was useful, would not be
#that cheap.....
#
Yes, but I find it a truly excellent powder in 6.5x55 mausers behind
140 grain bullets. You need a case full (49 grains), but the small bore
helps with the pressure curve and accuracy is on par with the more
expensive powders.
-Bruce
Socorro, nm
Clark Magnuson
Clark
S Hevelin
The rifle in question probably can handle .458 mag loads. That is because the
engineers at the company know that product liability is more important to the
company than "maximizing" the design. Most modern guns have a tremendous
safety factor, which can be abused (or used) by the shooter. Probably you will
run out of shoulder before you reach .458 loads.
Scott
------------------------------------------------------------------------
Please find out about rec.guns at http://doubletap.cs.umd.edu/rec.guns
*** Rec.guns supports MPFO's Millennial Rifle Raffle - donate today! ***
fl...@alaska.net
# The rifle in question probably can handle .458 mag loads. That is because the
# engineers at the company know that product liability is more important to the
# company than "maximizing" the design. Most modern guns have a tremendous
# safety factor, which can be abused (or used) by the shooter. Probably you will
# run out of shoulder before you reach .458 loads....
I can agree with the last comment fully, but the premise above it is
of doubtful validity, or at least a potentially dangerous assumption.
The HandRifles are designed for cartridges like the .30-06, which has
a SAAMI max allowable pressure of 60,000 psi. Proof loads for this
cartridge are on the order of 80,000 psi and above; this gives a force
applied to the breech of ca. 11,000 pounds.
The .458 has a a SAAMI pressure ca. 64,000 psi, for a force of ca.
10,500 pounds. This mean that firing a factory .458 in a HandiRifle
is like firing a .30-06 proof load...and NO ONE I know would condone
this practice. We just don't know if the HandiRifle is safe at this
level for day-in day-out firing. Proof loads are NOT meant for
continuous use!
It is possible that the HR is safe at this level, but the factory
doesn't chamber it for magnum cartridges. They MAY have a safety
reason for this. Does the poster KNOW what the design safety factor
is? Is that safety factor to full metal failure, or action stretching
to deformation, or what? The current HandiRifles are virtually
identical to my 1977-vintage H&R, with the exception of being made of
stlle rather than cast iron. How much over-enginering was used here?
How much more or less important was low cost with market appeal?
My level of 'outrage' here is not meant to flame the poster, but to
reaffirm that average shooters do not know the real design strengths
of individual firearms, and that making assumptions 'can' be
dangerous. All shooters need is a raft of blow-up injuries to help
convince the public that our sport is unsafe and needs more government
regulation.....for the children. ;^)
Jay T
Clark Magnuson
# Just a brief comment on firearm strength.
# engineers at the company know that product liability is more important to the
# company than "maximizing" the design. Most modern guns have a tremendous
# safety factor, which can be abused (or used) by the shooter. Probably you will
# run out of shoulder before you reach .458 loads.
Yes, it looks like the NEF Handi Rifle action will handle more pressure
than the brass. I won't run out of shoulder before I run out of case
volume and brass pressure.
The 3 loads for the 45/70 are the trapdoor 28,000 cup derated to 21,000
cup, lever action 28,000 cup, and modern single shots 35,000 cup. The
458 Win mag is 53,000 cup with a larger case capacity and it's belted
brass design.
The Trapdoor Springfield load 48 gr of IMR4895 behind 405 gr lead
should produce 18,900 cup. Bullet momentum = 1600 fps 405 gr = 648,000
fps gr. The gun weighs 6.5 lb without a scope =45,500 gr. The gun's
velocity = bullet momentum/gun weight 648,000/45,500 = 14.24 fps.
Kinetic energy = [fps] [fps] [gr.] /450,400 = [14.24 fps][14.24
fps][45,500 gr]/450,400 = 20.5 foot pounds of recoil energy. The bullet
will have [1600][1600fps][405gr.]/450,400 =2,300 foot pounds of energy.
Modern single shots 60 gr of IMR4895 behind 405 gr of lead makes 1997
fps, for 28.4 foot ponds of recoil energy. The bullet will have 3,586
foot pounds of energy.
A 458 Win Magnum 400 gr bullet at 2429 fps will have 5,240 foot pounds
of energy. A Winchester 70 458 mag weighs 8.5 lb. it its kick is 35.2
foot pounds of recoil energy.
If we compare this to a 7 1/2 pound Remington 870 shooting 2 3/4" trap
loads of 1 oz at 1185 fps recoil is 11.3 foot pound recoil energy.
The same shotgun shooting 3 1/2" magnums 2 1/4 oz at 1150 fps produces
57 foot pounds of recoil energy.
Clark
S Hevelin
I didn't mean to cause a stir. My statement that the HR could possibly handle
the .458 pressures was just a general comment. It probably could be construed
by some as a "go ahead" to do that. Far from it. A shooter could probably use
a few overloads in the .458 range, but the effect on the gun probably would be
well beyond it's long term design limits. You could possibly get into the
yield range of the steel, and bend things beyond repair. Don't do it. My
comments were not meant for the idiots who would think that this was OK, only
to say that there is some margin for increasing performance on most guns. Take
this gun out on a hunting trip with .458 loads in the chamber, fall in the
creek at the same time the big deer comes out of the thicket, fire the gun full
of water and watch your gun disintegrate (if you can still see). These kinds
of situations are why the guns are over-engineered. You use up your margin of
error when you overload things.
My original thoughts were that anyone who can fire a 6.5 pound rifle with .458
loads is tough enough to have the shrapnel bounce off, anyway. Incidentally, I
am a gunsmith/engineer who routinely does hoop stress/cartridge thrust
calculations on shotgun barrels, drilling rechambering,etc. during the sleeving
and rebarreling process. In fairness, I have to confess that I have never done
an analysis of the HR, and do not know the true strengh of it. Should have
kept my mouth shut about this gun.
Scott
Clark Magnuson
suggested that the breech may blow off the barrel. My father has
designed many guns and so I asked him how to calculate this. He said add
the shear to the bending stress. He said the bending stress is the
bending moment divided by the sectional modulus. The sectional modulus
is cross sectional shape dependent so I just got the formula for a
rectangle.
I have been applying jr. high algebra and college freshman calculus to
electronics for 22 years. I have been applying math to guns stress for a
couple of weeks. My ignorance of different steels is a problem too.
Could you explain the idiot proof way for calculating the stress in a
thick barrel? I've got the thin barrel stress =(pressure)(inside
diameter)/ twice the
thickness of the walls
------------------------------------------------------------------------
Clark Magnuson
intelligent inputs and I am trying mostly to learn how one calculates
the
strength of a gun. The following are the posted concerns and what I am
doing about them:
1) Concern: The WC860 load calculation is fraught with erroneous
assumptions
Corrective action :I found a load for the 8700 [interchangeable with
WC860] in a 45/70 in
the Accurate load book. The 500 gr bullet leaves faster than the 400 gr
bullet when they are both propelled
by 60 gr of 8700.
2) Concern: Failure to calculate the stress on the latch.
Corrective action : [At 50,000 psi chamber pressure] The latch lodges
between the receiver and barrel. The
contact is .16
x.61". The hinge pin is 16 degrees off the center of barrel measured
from the breech face. The shear force is then [sin (16 degrees)] 9817 lb
= 2706 lb of shear. The shear stresses = F/A = 2706/[[.16][.61]] =
28,000 psi shear stress on latching surface of barrel. The latch itself
sees 28,000 psi of compression.
3) Concern: The formula for thick walled barrel stress is different than
thin walled.
Corrective action: I am trying to get that formula. Unfortunately
someone posted it, and I could not absorb it on first reading. I am now
searching for that formula.
4) Concern: No calculations for the breech of the receiver failing.
Corrective action: I have obtained the formula for tearing an L shaped
structure as the shear plus the bending stress. The bending stress is
the
bending moment divided by the section modulus. The bending moment is the
force time the ditance. The section modulus for a
rectangle cross section is B times D squared divided by 6. Where B is
the left to right dimension of the breech and D is the front to back.
This is still in work.
5) Concern : The inside diameter of the case should be used to determine
area of force not the outside diameter.
Corective action: Well, its worst case with lube left in the chamber.
Clark
fl...@alaska.net wrote:
> ...
fl...@alaska.net
# I didn't mean to cause a stir. My statement that the HR could possibly handle
# the .458 pressures was just a general comment. It probably could be construed
# by some as a "go ahead" to do that....Should have
# kept my mouth shut about this gun.
Not at all, and if my response was too extreme I do appologize - no
offense was intended. But as we all know, there are a lot of people
who believe 'everything' they read on the Internet, and in the
interest of safety for all it is probably wise to qualify statements
like the above, which could be misconstrued.
While it may be difficult to imagine, there are shooters so clueless
that they will do almost anything with their firearms. Just ask a
full-service gunsmith, or go the the range before hunting
season....I'm constantly shocked at what I hear and see! The most
recent comment I heard at the range from a long-time shooter - "I
always start with the maximum loads shown in the manuals...if they
weren't guaranteed safe then the manuals wouldn't list them." !!!
Jay T
Clark Magnuson
110. It seems some guy he knows loaded a rifle case full of pistol
powder and ate a bolt. I'll keep my 110 and reload per the Speer manual.
Clark