.22LR Velocity vs Barrel length
Clinton Mills
I'm intrested in the velocity attained by a HV .22LR at various
distances down a barrel (internal ballistics).
What velocities does a high velocity .22LR attain from say 4"-24". What
is the effective trans-sonic velocity point down the barrel (for a round
typically exiting @1250fps for a 24" barrel, at what distance down the
barrel does it reach say 1095fps)
The second part is the slow-down from drag & friction from an overly
long barrel (ie what is the loss of velocity if all the pressure were
released behind the bullet).
I've heard people say that the velocity drops 20-25fps per inch under
24". From this a round should be subsonic at 14" (but winchester
powerpoint HV still has a super-sonic crack at 11.5" and another
aquaintaince said that a HV round is supersonic in a 10" freepistol?)
I've seen some internal ballistics programs on the web but don't know
the parameters for all the input fields so I'm only guessing in the end
Any help would be appreciated
thank Clint Mills
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Doug Owen
Clinton Mills wrote:
#
# I'm intrested in the velocity attained by a HV .22LR at various
# distances down a barrel (internal ballistics).
#
This is often determined experimentally, the barrel is cut off a bit at
a time and the resulting velocity measured. It varies vastly with the
round used. .22 LR is really a surprisingly high pressure round with
very high expansion ratios in rifle barrels.
#
# The second part is the slow-down from drag & friction from an overly
# long barrel (ie what is the loss of velocity if all the pressure were
# released behind the bullet).
#
You don't even have to go as far as releasing the pressure. Typical .22
LR rounds reach maximum velocity in just over a foot (say 14 to 18 inch)
barrels, and actually shoot slower in a 24 incher. Friction is quite
high (it provides most of the barrel heat) and the pressure is dropping,
the bullet actually slows down.
# I've heard people say that the velocity drops 20-25fps per inch under
# 24". From this a round should be subsonic at 14" (but winchester
# powerpoint HV still has a super-sonic crack at 11.5" and another
# aquaintaince said that a HV round is supersonic in a 10" freepistol?)
#
# I've seen some internal ballistics programs on the web but don't know
# the parameters for all the input fields so I'm only guessing in the end
#
Small arms don't really model all that well, and the smaller the worse.
This is nearly the smallest. This means lots of wall for the small
volume. All the rules bend. It is not realistic to expect a ballistic
program to model this well at all, that's why folks saw up barrels from
time to time testing this.
# Any help would be appreciated
#
Wish I could be more so. OTOH, it should be a fun afternoon snipping an
old rifle barrel off, bit by bit. You've a problem if you try to go to
short legally of course. You then begin your test of long barrel
handguns....
Doug Owen
Flint
for barrels of different lengths (determined by cutting the barrel between
test batteries):
Barrel Length Remington High Velocity Winchester T22
4 in 1045 fps 1005 fps
8 1150 1105
12 1220 1155
16 1240 1165
20 1235 1160
24 1210 1140
28 1170 1075
I hope that's readable, and I hope it helps.
Flint
Clinton Mills wrote in message <7j2em3$60b$1...@xring.cs.umd.edu>...
> ...
Seismal2
michael brady
# What velocities does a high velocity .22LR attain from say 4"-24". What
# is the effective trans-sonic velocity point down the barrel (for a round
# typically exiting @1250fps for a 24" barrel, at what distance down the
# barrel does it reach say 1095fps)
I collected the following notes last fall. Next time I'll shoot fewer
brands and include 18.5 and 23/6 inch barrels...
Remington Subsonic Hollowpoint, part # SUB22HP
Barrel length Average
3.27 766
7 934
10 972
16.25 1016
CCI MiniMag, part #00034
Barrel length Average
3.27 969
7 1126
10 1165
16.25 1243
Winchester Super-X High Velocity Hollowpoint, part # X22LRH
Barrel length Average
3.27 961
7 1092
10 1185
16.25 1238
Remington High Velocity, part # 1522
Barrel length Average
3.27 913
7 1103
10 1144
16.25 1169
Remington Yellow Jacket Hyper Velocity, part # 1722
Barrel length Average
3.27 1066
7 1273
10 1288
16.5 1380
Remington Target Standard Velocity, part # 6122
Barrel length Average
3.27 884
7 1049
10 1099
16.25 1141
CCI Blazer, part # 00021
Barrel length Average
3.27 948
7 1146
10 1185
16.25 1257
CCI Stinger, part # 0050
Barrel length Average
3.27 1180
7 1480
10 1514
16.25 1594
Dlmech
Using a new Ruger 10/22 bbl. and cutting off 2" at a time.
Ammo was Winchester Wildcat 22lr. at 60deg.f
18.5" = 1,229
16.0" = 1,226
14.0" = 1,212
12.0" = 1,197
10.0" = 1,175
8.0" = 1,152
6.0" = 1,088
4.0" = 1,004
2.0" = 794
...Randy
Jerry
Clinton Mills <c.m...@chem.canterbury.ac.nz> wrote:
#
# I'm intrested in the velocity attained by a HV .22LR at various
# distances down a barrel (internal ballistics).
#
The 1995 'Shooters Bible' has an article 'Beware the dangers of low-
power ammo' which has a chart on .22 bullet velocity versus barrel
length. They credit D. W. Cochrane, a firearms examiner for the Royal
Canadian Mounted police for the study in 1979.
The chart is for Winchester HV while they say other brands were
included in the study and were the same for practical purposes.
len vel
1 606
2 820
3 940
4 1010
5 1049
6 1087
7 1115
8 1136
9 1158
10 1210
11 1200
12 1200
13 1200
14 1195
15 1205
16 1216
17 1216
18 1212
19 1199
20 1212
21 1237
22 1213
Super sonic at 7 inches, hope this helps.
--
Jerry,
shooter, reloader and general gun lover
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