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7.62X39 twist rates
jplookster
Member Posts: 73 ✭✭
Wondering what is typical twist rate for SKS, AK's and Ar-15's in this caliber. And why.
I have 2 Colt uppers a 16 and 20 inch that are stamped 1 in 12. Yet most other manufacturers 7.62X39 AR's are 1 in 10. (The 16 inch colt upper is very accurate sub MOA. I have not fired the 20" yet).
Curious about the method behind the madness.
I have 2 Colt uppers a 16 and 20 inch that are stamped 1 in 12. Yet most other manufacturers 7.62X39 AR's are 1 in 10. (The 16 inch colt upper is very accurate sub MOA. I have not fired the 20" yet).
Curious about the method behind the madness.
Comments
As the 7.62x39 mainly uses the shorter (read lighter) for caliber bullets, the slower twist rate will be more than acceptable.
1:10 has been the "standard" twist for 30cal barrels since the days of the Krag with its long 220gr slug and fairly low velocities, but the 7.62 NATO (with it's 147gr bullet) went with the 1:12 back when it was adopted as a standard round.
Note that most 7.62x39 rifles (including the SKS and AK varients) tend to overspin the bullet, leading to poor short range, but decent midrange, accuracy.