Several years ago I had bad experience with RL22.
I had been loading for the 300 mag and everything was fine with the first can, I was 1 gr under max in the books.
Then I start a new can and dropped 2 grs and loaded 3 shells for testing. Well...that's when it happened, first shot locked the bolt up. Had to drive the bolt out with a 2x4 board and big hammer.
Well I finally got the bolt out, but now the case is still locked tight in the chamber. Next I had to drive the case out with a steel rod and the big hammer. But I did get lucky and didn't hurt anything.
I done some more testing by dropping the charge down 5 more grains. So from what I could tell this new can was about 5 grains to "hot".
So, a great big lesson was learned here. I have never, ever, had any other brand of powder do this to me after 30 some yrs of loading.
Now, I reported this to the owner of the gun shop that I buy powder from and he was telling me that I was the 3rd person in the last two weeks that had told him of this.
Two years ago on a forum, there was a topic on this powder and a man from back on the east coast had mention that he had gotten hold of exceptionally hot lot of RL22 also.
Sooo...always start low and work up.