Case bulge 45-70
Out of my Marlin 1895 lever (post 72) with microgroove, I have been shooting IMR4198 with 300gr partition.
At 46-47gr, I get a slight bulge above the rim. With new brass (winchester) as a comparison, I get a .0054" bulge using starrett mic's. Woudl that be of concern to those who understand and look for this expansion? It is noticable. Primers look great. I am getting around 2050fps.
I need to go thru my old remington brass to see if I see the same. I did all my original load development with remington brass from 41gr-51gr. Nothing stuck out in my mind as an issue. I was told by Brian Pearce from handloader and rifle mag, that this action (1980's) can easily digest this load up to 51gr. Nosler also told me the same. But lymans and Sierra back off majorly for any leverl, post 72 or not.
I get 1.5MOA accuracy at 100 yards with 46gr, but it starts stringing vertically past that.