Re: vertical strings with Wyatts magazines
It is 95 degrees and 70% humidity here today so hard to get good data. If you leave the guns out the barrels don't cool. If you take them in they get cool but when you take them out they condense. This being said the first shot out of both guns I take with a grain of salt.
I shot a four shot group with the 416 Rigby one at a time with none in the magazine three shots in .544" with the first shot opening it to 1.084". If I take the last two shots of the previous group it would be a 5 shot group of just over 1/2"
I shot a three shot group with the 375 RUM with the magazine full but not taking one out, I would put a new one in each shot. The group measured 1.5" but the last two were touching. Due to the condensation I didn't think the first shot was representative so I loaded two more. The last four were then touching .712".
I also shot two solids out of each gun they were right at .75 for each gun.
I know that this could have been done better but the barrels heat up very fast, and these guns really kick so I didn't want to shot to much more at one time.
I think you are right about the changing pressure on the bottom of the bolt as the magazine is used up but I don't have a solution.
Thanks for any help, these guns and I need to go to Africa in two weeks. I just need to get them to shoot ok then I can have them worked on when I get back if I need to.