jayinsat wrote: There are a number of reasons we frequently load and unload:
1) I like to dry fire practice in-between range visits and IDPA matches. Don't want to do that with a round in the chamber. I wish I had more guns that I could use an alternative, empty weapon. ALAS I don't. Working on it.
2) I shoot my carry gun monthly either at the range or at IDPA. I don't want to shoot my JHP's so I unload them to load my FMJ's. Too expensive to replace JHP's, especially Hornady Critical Defense.
3) I NEVER, EVER, hand my loaded gun to another. I will ALWAYS unload it. I chat with a lot of 2A friends and we're always handling each others firearms.
Just a few reasons why we feel the need to load/unload ammo. If I take it off at night, I just place it in my Uncle Mikes, fully loaded, next to my bed.
I can see that there are good reasons to unload, but I don't think they'll result in setback if you use good ammo and you don't do them every day.
Setback seems to happen most when somebody unloads every day and chamber the same round every time. This is going to be 30 loads a month on the same round. If you mix up rounds in a 10 round mag and only unload twice a week, then it would take you around 3 years to load the same round 30 times and you should have replace that ammo by then anyway.
I may unload my carry gun once or twice a month and I always line up the rounds and check for any differences in length. New Speer 9mm usually has a variation of a few thousandths. I've never seen anything outside that range even on ammo that I have carried and re-chambered over a few months. I'm sure there is some variation based on feed ramp polish and other factors.