Savage Twist

[RickP]

I note with interest that the rate of twist for Savage Arms chambered in 223 is 1:9 and in 22-250 is 1:12.

Am I to understand that a greater rate of twist is required for higher velocity bullets for a given caliber? What is this relationship?

Thanks in advance for sharing your knowledge.

 

[aheppner]

faster rate of twist is required for longer bullets,

so lets say you want to shoot 40gr bullets out of your 22-250 - a 1 in 12 twist would be good for that

but if you wanted to shoot 70gr bullets a 1 in 9 twist would be better,

1 in 12 is slower than 1 in 9, the 1 in 12 twist might not stabilize the longer bullet and it might keyhole

 

[aheppner]

i shoot a savage .223 with a 1 in 7 twist, this twist rate can shoot 80 or 90 gr bullets.

iv shot 55 gr bullets out of it but they didn't shoot well

I use 80gr A-Maxs mostly

 

[paperslayer]

The longer a bullet, the more RPM it needs to remain stable in flight. Obvioulsy there is a correlation between length and weight, so people tend to express it as the 'heavier' a bullet, the more twist needed. Varminters tend to want very fast, short-range flat shooting bullets, so the twists for that application tend to be "looser". Those that are more long-range/precision oriented, tend to want the long, high ballistic coefficient bullets, and these need more twist. erring on the side of more twist is a better choice as you can often use lighter bulles without a problem. High velocity and tight twists can cause bullets to disintegrate in flight though, so running a 40 grain bullet from a 220 swift in a 7 twist is likely a bad idea.