Question about a gun shot to the upper arm?

45ACP is known for penetrating very well. Therefore it is likely the bullet would pass through as long as it missed the humerus.

If the bullet is FMJ, Full Metal Jacket, then it would not expand or deform unless it hit a bone. The wound channel would likely be relatively small. There would be bleeding, but nothing major as long as no major vessels were hit.

Muscle damage? I haven't done any reading on rehab. Think of it like a stab wound. I'd assume a few weeks of minimal use. A month or two to get back to full strength. That's assuming it is treated well, medically. Double or triple that if there are any complications.

As long as nothing major was hit (bone, blood vessels, nerves) and there was no infection, the character would not need to see a doctor. But there are doctors who don't report gun wounds in real life. I'm sure there could be one in your book's world. Having a doctor's care would probably speed up healing.

Have you considered that if you don't know, most other people won't know if you just made it up as you went along? What is the shooter likely to carry? If it isn't too serious a wound, it's a small-to-medium pistol bullet (9mm, .380 auto, or what's considered a 'ladies' round, a .25 auto). And a solid bullet, not expanding (hollowpoint). A heavy enough round striking bone would break it and need to be removed. A small enough round might stop inside and still need to be removed. A fast, small round might pass through and not need medical attention. Stay on the small side. Don't make it a .45 or anything magnum.

Wow! Begin with what kind of firearm, rifle or pistol, or shotgun. Then what caliber? Close range? 500 yards? These are the major factors effecting the wound overall. What kind of clothes has the person got on? leather might stop, or extremely slow down birdshot out of a shotgun at 50 yards, and would stop rocksalt completely. However, a large caliber rifle at 500 yards might rip his arm off. (50 caliber).

It somewhat relies upon on the quantity of the harm. in case you require surgical treatment or have lost somewhat some blood and choose a transfusion/fluids/IV antibiotics it might desire to be dissimilar days, yet whilst the wound is minor it might desire to be much less.

http://www.sportsinjurybulletin.com/archive/0405-h...

try

http://guam-dl.slis.ua.edu/clinical/emergency/cond...

I dunno, maybe you can call up a local hospital and arrange a short phone interview with doctors who've had patients with those experiences.