So, you‘re basically wasting your time......? Enjoy.Here are the results of two tests using Remington Range FMJ 9mm cartridges.
The initial cartridge overall length was 1.114".
Using a Makershot magazine loader with a stock 12rd Sig mag with 11 rounds already in the magazine, I loaded and unloaded the 12th rd using my finger on the tip of the bullet to push it back into the magazine 10 times. At the end of the test I measured the cartridge OAL to be 1.114". No change.
Using the SAME cartridge and the same Makershot loader, I proceeded to load it into a stock 12rd Sig mag with 11 rounds already in the magazine, making 12 rds in the magazine total. I inserted the magazine into my Sig P365X with the slide in battery. I retracted the slide and locked it backward. I removed the magazine, removed the cartridge under test, and measured it. I repeated the test 9 more times. At the end of the test I measured the cartridge OAL to be 1.114". No change.
Which means that using the Makershot loader, I loaded and unloaded the same cartridge as the 12th round in the magazine 20 times with no change in setback. This doesn't necessarily debunk someone's claim on Sig Talk that using the Makershot loader caused bullet setback for him. But I'd like to see him replicate the setback using the same ammunition with which he originally had the setback problem. It could have been that the cartridges he was using had loose bullets. But for myself, I'll perform some type of test on every brand of ammo that I use to make sure that they won't be prone to bullet setback problems. Eazy peazy.
On the second test it required a considerable amount of effort to rack the slide with 12 rounds already in the magazine. It didn't cause the bullet to setback, but it did cause deep scratches in the brass that I can feel with my fingernails.
The question that this raises for me is: "When carrying with one round in the chamber and 12 rounds in the magazine, could the amount of force that the magazine springs exert upon the cartridge increase the friction against the cartridge enough to cause a failure to feed?" If there no failures to feed in this condition when the RSA is new, could failures to feed in this condition occur as the recoil spring becomes weaker with age?