Can't help with the 44 loads, but can relate to killing a chronograph with a gas check. I decided to see how fast I could push my 310 gr cast bullets in my 480. They were a plain base design so I seated a gas check upside down in the case under the bullet. Before the range session I thought I should put a piece of lexan in front of the chrono for protection, but didn't end up bothering. I forget how many shots I got off before a gas check connected with the front of the chrony with enough force to put a healthy dent and kill the electronics. As I recall I was getting over 1400 fps.