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Sub sonic barrels?

dreamlander

Sergeant
Full Member
Minuteman
Mar 8, 2009
193
2
40
North Dakota, USA
I am looking at getting a new 10/22 build. I am pretty sure I am going to go all out and get the Kid barreled action with a B&C stock. I shoot subsonic Wolf and Lapua ammo. I have read somewhere that some barrels have a 1 in 9 twist and are designed to shoot subsonic ammo. Does anyone know what the twist rate is on the Kid barrels? Is worth it to go for a 1 in 9 barrel? Or should I just get the Kid. Either way I will be using Kid parts for the rest of the build. The Kid trigger is unbelievably good!
 
Re: Sub sonic barrels?

From what I've read the 1:9's are only necessary for the 60 gr. subsonic ammo.

I pulled a wolf match extra apart once to get the bullet length, I think it was .475" but don't quote me on that. Putting that length with 1050 fps, which is about the average I got shooting them through a chronograph, into Brian Litz's Point Mass Ballistics Solver software gives a stability factor of about 1.3. In his book he recommends a stability factor of 1.4 but the bullet is only "technically unstable when the factor is below 1.0. In theory a 1.3 stability factor should be enough so the 1:16 should be alright. 1:9 gives a stability factor of 4.1 which is overly excessive. Shouldn't hurt to overspin them, unless you have really shitty bullets, it's just not necessary.
 
Re: Sub sonic barrels?

.22LR velocities are sensitive to barrel length. The general thinking is that it develops its peak velocity in barrels of 16"-17" length. Shorter barrels generate less velocity by failing to complete the propellant burn, longer barrels generate less velocity because the internal friction from the added length tends to decelerate the bullet somewhat.

The larger difference here is that the longer barrel may also tend to have a lower muzzle pressure wave, reducing the sharpness of the report. This might be a help with sound suppression.

Greg
 
Re: Sub sonic barrels?

Recommend you try the heavy stuff before you assume it won't stabilize. I shot the Aguila 60g SSS load out of my Savage Mark II-FV (1:16 twist) a week ago...1.25" and 1.4-ish" five-shot groups at 100 yards. Won't happen with every barrel...but you can't Know until you try.
 
Re: Sub sonic barrels?

Ok, it sounds like I will just stick with the normal barrel twist. I am not planning on shooting the 60g bullets. I just thought there might be some accuracy improvement with the 1:9 barrels for the 40g sub loads. Doesn't sound like the case. thanks
 
Re: Sub sonic barrels?

I shoot a remington 504T and it only likes High quality subsonic ammo. Remington subs suck balls in it. But copper cci's just hum through it. I tried some 60s SS the other day just for laughs and they shot great also at 35 yards. I'm not sure if they'll tumble after that, but at 35 yards they grouped tight. On a side note if anybody wants a clean hard hitting subsonic I recomend the cci Quik-Shok Subsonic 40Gr Hollow Points. They hit hard and are pretty quiet. But they are pretty expensive and hard to find. They are around 6$ per 50 when you can find them.
 
Re: Sub sonic barrels?


the best subsonic I have used out of a normal twist 22lr , is Lapua's Scoremax , it's subsonic , very accurate & has the heaviest rimfire bullet that will stablish in std twists , the weight is 48gr .

Its not the cheapest , but it is a good hard hitting subsonic round .

Later Chris