Chamber danger?

[45springfield]

I have a 1945 Springfield m1 Garand. Appears to be in excellent condition and all original except a nm operating rod which leads me to theorize that at some point someone used modern ammo with the original gas plug, bent the rod and replaced it with a nm rod. Anyways I thought it would be cool to use it to bag my first deer with it using it as is iron sights and all, trouble is surplus 30-06 fmj or modern ammo made specifically for a m1 isn't suited for hunting so I installed a aftermarket gas plug and took it to the range with modern hunting ammo to sight it in. I got the best groups with barns vor-tx 168gr ttsxbt ammo so I sighted it in with that. So far so good no problems or visible damage what so ever so far, BUT I did notice my spent shells had a slight bulge all the way around near the base of the shell. It is visible and you can feel it with your finger. After noticing this I examined other spent shells of of other brands...federal fusions slightly less bulge, ppu fmj m1 load even less bulge and some old 67 LC no bulge at all. I can't visibly see any damage or signs of wear in the chamber at all and the gun functions flawlessly so my question is am I doing damage to my m1 or is this normal? Just fyi the muzzle velocity of the barns 168gr ammo is 2850fps.

[TJT]

Is that bulge all around the circumference or just in one spot? If it's all around, there could be a head space problem. If it's just in one spot, there's a flaw in the chamber.
Jon

[Smokey]

First, have a gunsmith check it out. Have the headspace checked as a precaution.

Some chambers are cut a little more generously than others. The case will expand to fill it, down to where the case gets thicker near the base or head. I see this in some of the surplus rifles I've worked with, and the headspace was OK. If you reload, the brass will get worked more leading to eventual splits. Don't know how many cycles this would take, and it depends on the brass. With a bolt action you can back off the sizing die or neck size. With the Garand you absolutely need to full length resize.

It the gunsmith says its ok, you should be fine just shooting factory ammo in it.

[lapriester]

As others have said, have someone check the headspace and inspect the chamber.