Chronograph Rimfire Ammo ;

[Levi Garrett]

Anyone ever check if there was a gain in Velocity from a 20 to 24 or 26 inch barrel..
on LR , WMR , or HMR ?

 

[prosper]

http://www.bullberry.com/HMRdata.html

HOWEVER, they seem to have a fetish for short barrels there, they also tested a 204 ruger, and 'proved' that a 23" was the optimum length, and that longer barrels showed a DECREASE. However, this has not been borne out by magazine tests or any other published info anywhere, so maybe take it with a grain of salt...

 

[hermie]

Chronographed some Aquila Mexican hyper velocity 22 lr with my CZ 452 and buddies 10/22. Mine with the 25" bbl was 1750fps, his 1550 fps. CCI Mini-Mags were virtually the same. BTW the Mexican stuff is not very accurate in either rifle but the CCI was.

 

[KDX]

Supposedly the optimum length for a .22lr barrel is 16.5" from what I have read on Rimfire Central. Longer barrels decrease velocity they say.

 

[Slash5]

I bought a couple of $25 Cooeys at the last auction to sacrifice and test this.

One of them is a great shooter, shoots almost anything under an inch at 40 meters. Good sights as well. Some donkey carved his initials in it. Shoots too good to wreck.

The other one is probably going to be the test rifle. It's loose in the stock so I might try bedding it for practice. Then it's off to the range with a chrony, hacksaw and umpteen different makes of ammo.

 

[KDX]

Nice to see a scientist among us. I wonder if there will be any big difference in the velocity.

 

[Eagleye]

Somewhere between 16.5 and 19" is the optimum length, depending on which 22 rimfire ammo you are using. We already did this experiment several years ago with an old Lakefield 22. We found that we needed to chrony about 20 rounds at each speed to see the trend. The ammo we were using was some imported HV stuff manufactured by a Winchester subsidiary in Australia and some Winchester T22. Highest velocity with the HV was at 18.5", with the T22 at 18" We started at 22" and cut back in ½" increments. The velocity loss was not large, but noticeable. IIRC, the average difference between the 22" and the optimum length was on the order of 25fps with the HV stuff and 23fps with the Standard. Obviously a different barrel might yield slightly different results. Some of the newer Hypervelocity rounds may make more use of barrel length as well, but I lack any proof of that. Regards, Eagleye.