Then several shots in the order of 5000-6000 fps. A second string started with 5000-6000 fps again. I stopped wanting to investigate further
I bet that was exciting! The most important thing you are learning is to STOP when things don’t look, feel, or sound right!
I second all the other cautionary posts. You have good equipment, but a powder better suited for an experienced reloader. Save the rest of it and continue with some other less-spikey powder. Always start low with charges and work up, evaluating each powder wt. as you go.
I particularly like W231, but have used AA#2, Promo/Red Dot, and am planning to try out True Blue next.
Come back here often and ask questions. You’ll be glad you did!