What is the proper twist for rim fire?

[Paul053]

Reason I ask is because I'm looking into the CMMG Evolution drop in kit for my 556 ar with a 1:7in twist But then started thinking about the dedicated upper from CMMG which comes with a 1:15in twist. Will the high spin caused by my ARs twist rate cause .22 rounds to disintegrate?

[Chaos47]

Disintegrate?
They wouldn't sell rimfire drop in bolts if they could make 22lr disintegrate...

How do you even think that it would disintegrate anyways? Its a 40 grain hunk of lead.. its not going to turn to powder. The force is propelling the bullet... for it to disintegrate it would need to impact something.

[Fjold]

The 1:7" twist is for heavier, jacketed, centerfire 22 bullets. The short rimfire (swaged lead) bullets use the 1:15" twist.

[G-forceJunkie]

Most dedicated rimfires are about 1 in 16.

[ejhc11]

My CMMG 22LR upper is 1:16. Drop-in conversions will work but will be less accurate than a dedicated 22LR upper, and your bullet impact will be off from your centerfire ammo zero unless you adjust.

Contact Calgunner: shadow65
For any rimfire AR questions.

[CSACANNONEER]

Proper twist rate has more to do with bullet profile, caliber and weight. It hs nothing to do with the type of primer the cartridge has. Even if we forget about all rimfires other than .22lrs, no twist rate will be idael for all .22lr ammo.

[call-in]

Maybe the Aguila 60gr SSS would shoot better out of the 1:7 barrel? I thought I read somewhere that the ideal twist rate for this ammo is 1:11 but people say it shoots fine out of a 1:7.

[Izzy43]

Maybe the Aguila 60gr SSS would shoot better out of the 1:7 barrel? I thought I read somewhere that the ideal twist rate for this ammo is 1:11 but people say it shoots fine out of a 1:7.

Rumor has it that the 60 gr SSS likes a 1:9 twist rate.

[donw]

my spikes tactical ST-22 is 1:16, a dedicated .22 rimfire AR...the 5.56 uppers for it are 1:9.

1:16 is the most common twist rate for the .22 cal rimfire.

a few years ago, i had a NEF .223 that in the owners manual, it cautioned against using bullets heavier than 55 grains in it's 1:12 twist rate, that they would suffer a degraded accuracy factor. and IIRC, it said the bullet could spin as fast as 103,000 rpm causing problems.

[JAGACIDA]

Marlin Model 60 is a 1 in16 twist. 11 million sold.

[SDM44]

My 15-22 is 1:16 twist rate. Most .22LR barrels are 1:16

[darqhelmet]

CMMG Upper 1:16
Marlin 795 1:16
Sig 522 1:16
GSG 5 1:16
Green barrel replacements for 10/22 1:16 or 1:9 for the "subsonic Sniper" Barrels.

1:16 seems to be the most common twist for .22LR

[shadow65]

CMMG is 1/16.
The 60 gr. Aguilla works well in a 1/9.
Dave N

[Fjold]

my spikes tactical ST-22 is 1:16, a dedicated .22 rimfire AR...the 5.56 uppers for it are 1:9.

1:16 is the most common twist rate for the .22 cal rimfire.

a few years ago, i had a NEF .223 that in the owners manual, it cautioned against using bullets heavier than 55 grains in it's 1:12 twist rate, that they would suffer a degraded accuracy factor. and IIRC, it said the bullet could spin as fast as 103,000 rpm causing problems.

Bullets heavier than 55 grains would not stabilize in your NEF because they are being spun to slowly to stabilize them. 1:12 twist is slow.

A bullet shot at 3,000 fps out of a 1:6" twist barrel would be spinning at 360,000 RPM.
Out of a 1:9" twist barrel it would be spinning at 270,000 RPM
Out of a 1:12" twist barrel it would be spinning at 180,000 RPM

[Paul053]

Disintegrate probably isn't the proper word. I recall reading an article that if you spun a bullet too fast it can cause a non jacketed round to come apart. The previous post said a 1/7 spins a round at 300,000rpm vs a 1/16 at almost half that.