I am in a quandry and in need of some advice. I have been trying to tighten up my groups for my MK IV Martini for several years now. I have posted the lastest targets in a couple of posts here. I have tried several bits of advise from several distinguished members and I still come up with a basic need to tighten things up even more.
I have slugged my bore again and found that in one spot on the slug I actually get a 472 diameter reading. The rest of the reading are around 469 or 470. I know now that the bores on the MK IV's tend to favour larger bullets and mine seems to be no different. The last bullets I fired were 469 diameter. I tried powder charges from 72 grains to 87 grains by weight and used both FG and FFG powder (Schuetzen). I have tried without grease cookie and filler and with grease cookie and filler. I used a blow tube and patched between...
I have slugged my bore again and found that in one spot on the slug I actually get a 472 diameter reading. The rest of the reading are around 469 or 470. I know now that the bores on the MK IV's tend to favour larger bullets and mine seems to be no different. The last bullets I fired were 469 diameter. I tried powder charges from 72 grains to 87 grains by weight and used both FG and FFG powder (Schuetzen). I have tried without grease cookie and filler and with grease cookie and filler. I used a blow tube and patched between...