Quoting an esteemed member's advice.
I had that issue on a big scale with a Win. M70 in 300 WinMag, and two of my .308s suffer that to a small degree when using some of the slicker bullets.
It's a matter of starting out at magbox confine and going from there. I've been lucky so far in that I've never had a problem putting an accurate load together, even if the jump is more than I really like, as was the case with the .300 WinMag.
