Spreading mouth of 308 case?

[dee]

Keep in mind the free bore is different on every rifle and they could have been measuring off the Ogive instead of the tip.

Also what grain weight Barnes did you go with? They need to be ran lighter weight than a normal cup and core bullet, due to copper not being as heavy as lead. Also watch for fouling during load work up some rifles foul really easy with those.

[Bassics]

I've heard of people using dry erase marker on a polished bullet to see where exactly that particular ogive touched that particular chamber, and reverse calculating from there.

It means seating and pulling several times. Maybe just switch to 45-70 and call it a day? LOL