Low versus normal velocity

[breadfan]

Can you please give your opinion about low versus normal velocity for 10 and for 25 meter rimfire?

For example:
-Low velocity +/- 275 meter per second is always an advantage (with less recoil)?
-Normal velocity +/- 330 meter per second: does higher speed have an advantage? Or is the difference in speed too small to let (extra time for) movement have a negative impact on 275 mps bullets?
-On these small distances (10 and 25 meter) is there something like stabilization in the air? Perhaps faster could mean less wobble on the first 10 meter?
-Are the general rules for the two speeds in ammunition the same for 10 and 25 meter?
-None of the above will be a guaranteed dis/advantage, what works best for you with your configuration might totally not work for somebody else? You could only try it out yourself, to find out?

[David M]

When talking Velocity you can open a can of worms with Pistol....
Firstly, there is Standard Velocity .22LR (usually sub sonic below 1080 fps) and there is High velocity (Supersonic).
For target shooting we need the slowest velocity to achieve the desired group, so stay sub sonic.
We do not need the unstable trans sonic range of flight.

The velocity advertised on ammo box's you need to dig into the mfg. test data but it is usually on a test barrel.
The SAAMI standard test barrel is a 24 inch, 1/16 twist barrel.
So the velocity we achieve out of a Target pistol barrel (between 4" to 6") is very different.

Example CCI Std Velocity .22LR 40g is facrory at (test barrel)
0 yds - 1070 fps 326 m/s
10yds -1055 fps 321 m/s
25yds - 1020 fps 310 m/s
50yds - 975 fps 297 m/s
Pistol velocity from chrono at 3 yds is 900-940 fps. 274-286 m/s
Thats about 150 fps slower. 45 m/s

When Rapidfire changed from shorts to longs the ISSF had the velocity at 280 m/s.
They used SAAMI test figures off the box.
Most pistol used could not achieve this speed, so at a couple of World Cups we convinced the
ISSF along with help from Walther to reduce to 250 m/s.(none of their pistol would pass with short barrels.)

Radipfire pistol miminum velocity is 250 m/s or 820 fps, and some ammo will not make this
velocity in a Rapid gun and you need to check it before a competition.

Air pistol pellets achieve their great accuracy from between 450 fps to 510 fps.
Home loaded centrefire ammo both .32 sw long and .38 special is set for 680 fps to 800 fps depending on the projectile.

.22LR pistol ammo will have a faster burning powder than rifle ammo for the shorter barrel.
Rifle ammo will work in a Free pistol because of the longer 12" barrel.

[David M]

Origional document from 2004 on Rapidfire ammo testing to ISSF
to change from 280 m/s to 250 m/s.
Note that non of the ammo passed in the Walther GSP.
Walther had a big input in changing the ISSF technical comittee mind....


Test .22 LR for Rapid fire
Test carried out with a short and long barrel Standard Pistol to see variation using European, American and Australian ammunition.. Velocities are averages of two by five shot groups with erroneous shots deleted. Published factory listed weight and velocity shown where possible, but most factory listed velocities do not list the test barrel length (Eley was the only one to list test length).

Ammunition Walther GSP Unique 96
(factory wt/velocity) (114mm Barrel) (150mm Barrel)

Winchester Supreme 279 m/s 295 m/s
(40g / 331m/s)

RWS Pistol Match 277 m/s 284 m/s

Federal Classic 266 m/s 283 m/s

Federal Target 269 m/s 288 m/s
(40g / 1080 f/s)

Eley Pistol Extra 261 m/s 275 m/s
(40g / 314 m/s with a 254mm test barrel)

SK Standard Plus 263 m/s 284 m/s
(39g / 320 m/s)

SK Subsonic 269 m/s 283 m/s
(39g / 315 m/s)

[breadfan]

Hi David,

Thanks a lot for sharing all the insight.

With "For target shooting we need the slowest velocity to achieve the desired group, so stay sub sonic" I think you mean sonic versus sub sonic?
Or literally go as slow as you can go?

I see you mentioned some of the typical slow ammunication (of what I can think of). RWS and SK for pistol shooting.

Perhaps I am wrong, but isn't it so that a lot of the top pistol shooters (in ISSF or olympics) shoot with Eley Tenex Pistol?

Velocity mentioned on the Eley website for Tenex Pistol is Muzzle : 326m/s (1070ft/s). This is exactly the same as can be found on the CCI website for the standard velocity.

Do you think Eley Tenex Pistol is too fast for pistol at a top level (not that I am at a top level sadly)?
In contrast to the rest of the world I have little interest in rapid fire. With top level I just mean static target shooting.
To make it more concrete, let's say 25 meter rimfire for women.

I think we can assume that Eley Tenex Pistol is a lot faster than RWS Pistol Match with +/- 55 mps or RWS Pistol Match SR with +/- 70 mps (based on company website info).

[David M]

You missed the point, The velocity on the web site is in a Rifle test barrel.
You will not achieve that velocity in a Pistol, you will get about 280-290 m/s.
That is well below the speed of sound so it is sub-sonic.
My pistol chrono's CCI Std at an average of 280 m/s well below the published velocity on the box.

From the Eley web sight.

ELEY tenex pistol overview

Strike Depth – 0.012-0.015 in
Recommended headspace 00.040-00.041 in
" Mean Velocity is determined in ELEY Rifle test barrels. Results may vary in your firearm. "
Drag Model – RA4
Ballistic Coefficient 0.112
velocity
Muzzle : 326m/s (1070ft/s)
25m (27yds) : 304m/s (997ft/s)
50m (55yds) : 291m/s (955ft/s)

[breadfan]

Yes sir, I stand corrected.

I was stuck in my own ideas in which I neglected the test barrel length. It's stupid because I know it has impact on the energy build up.
This way the RWS ammunition seemed special with it's low velocity (based on tests with a 13 cm barrel).

For the silly people like me, I take the liberty for a small review on my first post.
Yes, you do have to try out what works best for you with your pistol.
Better use "pistol" ammunition. When tested with an equal barrel, most pistol ammunition is a bit arround the same velocity.
Other aspects will also play a role, so better try it out yourself.