Well, it was mounted on a pretty sturdy tripod
I need to reload some more shells now. I figure on doing another test this week, probably Wednesday evening.
I didn't notice your comments on the mag primers before. I may try to get some small rifle primers locally and try them also.
Is there a way to find out how many feet the test barrel was from the chrony when Hornady developed their recipe? Or is 10' just a common distance everyone uses?
Thanks for all of the replies.