Now I know why some guys shoot 3 round groups...

[Aircraftmech76]

AMAX'S: an SST without a cannelure! (At least in my and other's experience)

Kevin

[helotaxi]

3 shots provide a very low statistical confidence level. You're essentially just as likely to get a small group as a large group and you can't be sure what is actually representative of what the rifle or load can do. If you want a representative sample and you're concerned about barrel heating, either wait a significant period between shots or shoot several 3 shot groups with a good cooling period between them and overlay the groups.

[helotaxi]

AMAX'S: an SST without a cannelure! (At least in my and other's experience)

Certainly not in .308. The SST has a longer ogive, lower BC and is a lighter bullet.