The load is about mid range as far as pressure is concerned for that size bullet in a Marlin. I'm guessing a slightly oversized or oblonged chamber.
If the case ejects without problems, no sticking, flat primers or extruded primer material around the firing pin indent etc and the accuracy is good then I would just live with it. Ive had quite a few factory chambers that were "wobbled" but didn't interfer with hunting accuracy.
Depending on how you have your sizing die set up or how well the die fits the fired brass, the longevity of the brass is probably the only issue.
YOU'RE SURE that your powder weigh scale and other equipment is calibrated and not totally screwed up?????
Did you measure the fired and sized case with a micrometer or caliper at the buldge?????
FWIW...my NEF BC 45-70 now 45-120 liked H4895 with the Hornady 350 bullet...it gave the highest velocity and best accuracy and lower pressures than the faster burning powders (RL7, H4227, H4198 etc) usually listed for this case. A couple of other powders AA2230 and AA2460 gave even better results, case longevity etc shooting 45-70, 45-90 anc 45-10 cased loads in my 45-120 and 458 American.
