After being told about these bullets and after seeing an article on Accurateshooter.com saying they were specially made to suit 10 twist barrels I thought I'd give them a try. However when I got the boxes of bullets through the mail it said for 9 twist or faster on the label. I have spoken with Sierra about this and they say that if I load them hot they may well stabilise in my 24" 10 twist barrel. As a novice reloader though my question to you guys is how hot should I go before I quit? I'll be using rem brass, br2 primers and imr4350 to start with. My rifle is 243win.