what you could try is the following:
1.) set up two total targets at 100yards.... one target for bullets that are handloaded with .010 jump,,,,, other target that is magazine feed by magazine length.
2.) mark one of the magazine length rounds on the brass body with an x with magic marker,,,, this will be your "dummy recoil impulse round" that you will NOT fire & will only be used to simulate recoil. it can be a live fire round, but you just will not fire it & will eject this round by hand.
3.) load up a magazine with the "dummy recoil impulse" round that you WILL NOT FIRE first, then an actual magazine length round after that which you will fire out of the rifle.
4.) handload your .010 jump round into the rifle, and then insert the magazine that has the two rounds as described above.
5.) fire your handload .010 jump round at one target, and then fire the magazine round at the other target as described above & EJECT BY HAND the "dummy recoil impulse" round (you will re-use this dummy round for 5 total shots for each target).
6.) repeat the steps above for 5 total rounds for each target and compare the two... you might need to do this twice for two total 5shot groups each to see if it actually makes a difference.
7.) just make sure you don't forget to NOT FIRE the "dummy recoil impulse" round.
this will not take long at all & will tell if you if the jump is actually making a difference or not..... OR if it is just recoil impulse as by handloading the round you are pretty much turning the semi-auto into a bolt action rifle.
Elf...are you saying seat to fit in the mag, but load one round in the mag and shoot one at a time? In that case I could continue to seat the bullets out and load one at a time into the chamber.....