It's very possible that your friend just doesn't have his F/L die adjusted properly in his press. I only have one rifle that required a Small base die, a Steyr SSG 69. All of the rest of my 308's ( SR-25, GAP 10 40XBKS, snug chambered Palma chambered 308 bolt gun and 2- M-1 A's ) will chamber using a regular F/L die.
Before going out and buying another die, Have your friend make up a few dummy rounds, turning the F/L die in a bit more. Sometimes, all it takes is turning the F/L die in another 1-12th / 1/24th of a turn to get it right.
A case gauge like bigedp51 suggested can tell you right away what the issue is. The Hornady Headspace / shoulder bump gauge was the best tool investment I made. You'll see the numbers on your caliper.