Regulations forbid military using privately owned guns, but Regulations are Guidence for the Commander, not doctrine. People do what they can get away with.
We werent suppose to have private weapons in Vietnam but a lot of people had them shipped over. I dont know how it was in the rear but I've never seen any commanders bitch if they caught us Grunts carrying a revolver their parents shipped over.
I have a M1911A1 and I supposed I could have had it shipped over but getting it shipped back home would have been harder. Never occurred to me since I had an issue M1911a1 anyway.
Its kind of what you can get away with. After I got out of the Army I joined the NG. We were using M16a1s at the time. Not liking dealing with unit armors, if we had to draw weapons for qualifications or anything else (including FTXs) I carried my SP1. No one was the wiser. After OCS I was suppose to have a pistol as a TO&E issue weapon. I carried my personal M1911a1 which kept me from dealing with the armor.
Even when they got the Beretta, being a die hard 1911 guy, I still carried my M1911a1 as if it was my issued weapon. No one was the wiser, those who knew the difference didnt care.
Also, I started the AK NG Sniper Program, while at the same time I carried a Model 700 Remington in 223 as a counter sniper rifle as a police officer. I often took it to guard drills and even jumped with it, mainly to see how it held up.
I also took it to the Sniper school, but I ran the school so that was no biggy.
I dont know how hard it would be now, (I retired in '92) but soldiers always have, and always will do what they can get away with.
As to the original poster I dont know about todays wars but I do know people sent their pistols home during Vietnam, not legally of course, but it happened. Weapon accountability was pretty lax in Vietnam. When I first got there, I was handed a M16a1 and told I'd better turn in the same weapon with the same serial number when I left or I'd be going to jail. Got to my unit and was told to trade it for an M-60. Throughout my tour, I traded the M-60 and M16 back and forth several times never worrying about the serial number. The issue never was brought up when I left.
But I dont know how many M1911s were issued in the Iraq war, that would be the question I would have.
My wife was activated during the first part of this Iraq war. She was issued a M16a2. Not sure she ever carried it. She was an Intel Clerk and if she left base she carried a Beretta. She broke her back and was medivaced out. I went over an was staying with her. We took her to the medivac plane. She didnt have her rifle, so I called her boss and told him it was in her office and he said he'd turn it in. No paper work, nothing. I guess he could have done anything with it. That was in late 2003 and we havent heard anything I guess he must have turned it it.
As Robert Service said, "Strange things have occured in the land of the Midnight Sun"
Anything is possible when it comes to GIs.