Did you try the "plunk test" without a bullet seated to see where your case was at resting on chamber shoulder case mouth junction? Diffrent bullet styles ogives will seat to diffrent oal lengths. I have fopund that most semi autos ( pistols more so) are more dependant on length of the loaded round than shape or wieght of bullet. To short starts feeling "clunky" just before jams start to happen To long and it feels "sluggish" and or slow before jams start to occur. Some pistols will feed empty cases from the mags fairly reliablly, yet choke on a bullet that isnt quite right. I have 2 Kimber 1911s that out of the box feed a full wadcutter bullet when loaded to the right over all length and choke on them when to short or to long. My 1911 in 38 Speacial has only seen hollow based wadcutters and hasnt jamed in better than a year that I can remeber. With soft lead bullets in BPCR rifles cases filling the chambers saves the lead ring effect from happening. Improving accuracy, question is is it from the case filling the chamber or the bullet not getting shaved down when fired? Boolits can be to hard as well as to soft both degrading accuracy, cases vary in thickness, case head, flash holes and primer pockets, also length but that can be controledor changed easy enough. So to get the ultimate ammo cases would need to be completly uniformed. A swage and heavy press to make all the case heads the exact same inside the case by re forming, Primer pockets all cut to square and exact same depth, flash holes reamed to same dia and sorted for center ( a gage made not eyeball) then deburred to same depth and shape inside the case. The re forming of the case head lengthens the case so trimming becomes needed, And then after all this work an annealing to uniform tension. Its all easier to type out than to actually do. Now considering that rimless straight walled cases headspace on the case mouth and are set to as such chambers probably only vary a few thousandths of an inch in length and cases a little more. Setting cases long enough so roll crimped ammo headspaces creates issues with bullet release as the case may not be able to open enough to let go of the bullet.