Barrel twist/stabalization question

[chet]

OK, according to POP's sticky about barrel twist....... I'm right on the verge here:

I want to try a 180g AB out of my 308win. Velocity should be an honest 2550. Barrel is 1 in 12.
the calculator says I should be alright, but my question is: Does the RPM of the bullet slow down as the velocity slows???? or does it stay the same? Can the bullet "un-stabilize"?

I'm sure the bullet would be fine out to 100 yards or so.... but i may ask this load to perform at 600 yards some day, will the bullet tumble when it falls below a certain velocity?

 

[DrMike]

You may get some yaw when velocity drops below 1000 fps or so. This is not a certainty, but a possibility. 1:12 seems like a fairly slow twist for the 308.

 

[chet]

on these kimber 84M's they use a 1:10 on the 243, a 1:9 on the 7-08, and a 1:12 on the 308......... kinda odd I suppose :|

 

[Guy Miner]

The 1:12 twist is standard on a lot of .308's, and I've had no problem stabilizing 180 grain bullets from mine. Even 190 gr Sierra Matchkings did fine.

Guy