Loaded up some rounds for my Weatherby 224. Weighed out 23 gr AR 2207 with 63 gr bullets. Data from Lyman, with powder equivilent from ADI (Australia). Scales from Lee.
First shot blew out the primer, blew off the magazine plate, bolt needed to be levered up when rifle was taken home.
Bullets pullled and powder weighed on different scales. Instead of 23 grains the charges weighted 30 grains.
I checked the scales: hadn't adjusted them since the above. Still set on 23 grains. If the ball bearing on this set of scales had been in the wrong spot (as those with the Lee scales will know) then charges would have weighed 33 grains.
This was extreamly embarrassing as my gun smith was the one who fired the shot. Luckily he held out the rifle at arms length for the first shot as is his practice and didn't get hurt. This was my major concern.
I don't know how this happened. I've loaded thousands of rounds and never had an issue.
Any ideas? Scales appeared to be ok. I have an electronic set of scales comming and between now and when they arive I will weigh a 40gr bullet and see how close it is.
But wow man, that was really bad! I felt like a real idiot but had carefully weighed out a minimum charge. So I thought.
Cheers James: may we all learn from this.
PS rifle is ok, which says a lot for Weatherby's inherent over engineering. Classic pressure signs: brass flow into ejector etc.