I know a writer for Sporting Shooter in the May edition found he could get the velocity of the 243 with a 64gr bullet (i think, it may have been a 55) up to 4500fps which is just amazingly high. The main problem I have heard of is reduced barrel life and when reloading there have been problems with the primer bursting after only 2 or 3 shots! At the moment I think I will wait a few months to see what owners have said about them...

M82A1