AR15 Barrels, best for 55gr?

[Boboclown]

What is the ratio depicting? Say 1/9? Is that bullet spinning 9 times when it leaves the barrel(16"/18") regardless of length or 9 times per inch?

1:9=One full spin per 9 inches of barrel.

 

[Medic!]

heres my .02... take it for what its worth. i shoot all weights through my 1/7 and 1/8 and dont notice any difference in accuracy with 55gr in either.

Ever have a 1/12 barrel? And see sub 1'' groups with 55 grain?
1/12 is gooooooood.



Twist rate?
A 1/7 barrel is one rotation per 7''. And 12''[a foot] divided by 7'' is 1.7142
rotations per foot. [Can we say 1.7?]

At 3,200 FPS x 1.7 that's 5,440 RPS.
x 60 seconds it's 326,400 RPM's.

Wow I'm kind of dizzy now?

 

[v0lcom13sn0w]

Ever have a 1/12 barrel? And see sub 1'' groups with 55 grain?
1/12 is gooooooood.



Twist rate?
A 1/7 barrel is one rotation per 7''. And 12''[a foot] divided by 7'' is 1.7142
rotations per foot. [Can we say 1.7?]

At 3,200 FPS x 1.7 that's 5,440 RPS.
x 60 seconds it's 326,400 RPM's.

Wow I'm kind of dizzy now?

thanks! my head exploded just now.

nah never shot with a 1/12. im no target shooter im more of a plinker/hunter than i am for shooting off of a bench.

 

[Stomper]

Ever have a 1/12 barrel? And see sub 1'' groups with 55 grain?
1/12 is gooooooood.



Twist rate?
A 1/7 barrel is one rotation per 7''. And 12''[a foot] divided by 7'' is 1.7142
rotations per foot. [Can we say 1.7?]

At 3,200 FPS x 1.7 that's 5,440 RPS.
x 60 seconds it's 326,400 RPM's.

Wow I'm kind of dizzy now?

Wuddaya mean, "now"?