308ar SB sizing die?

[SilverDragon]

I've been reloading 7.62 brass and found that using a standard sizing die doesn't work for my gas gun. I do check the cases with a Lyman case gauge and they check out. A SB sizing die does work the brass a bit more than a standard sizing die, giving that 7.62 brass has a thicker wall, I doubt this should cause a problem. I have seen a 308ar SB sizing die offered, but states not for use with bolt action firearms. My question is why, does the AR sizing die work the case too much? I don't want to invest in both an 308 SB sizing die and 308ar SB sizing die. Anyone know the difference between the two sizing die types, if there is any.

[Sisco]

I am surprised it says not for bolt action firearms. I have been using a small base sizing die for my bolt and pump action 30-06’s since 1979. For semi auto 308’s the SB die is necessary because you need to resize the whole case, as opposed to the upper 2/3 of the case, for feeding and ejection reliability.