I have been loading some 115's over 4.7 of 231. I am experiencing some random tumbling from several different pistols. Bullet weight is pretty consistent and I'm putting minimal crimp on these loads.
Over twenty years of reloading and this is the first time I've encountered this. Same results out of some of my buddies pistols too. Cleaned, inspected, yadda yadda yadda...
Bullets are Winchester 115 FMJ's on a 550b with Dillon dies. Mixed brass, mainly winchester headstamp.
What could be causing this?