I've had an old Australian black and white reprint of this issue since I was a kid.
Looks like John Romita Sr. copying the generic gun that Jim Steranko copies off Jack Kirby, which is usually an M-1 carbine.
Kirby draws everything like it was made of Lego, but basically correct, as he served in WW2, but Steranko adds widgets and greebles, then John Romita just kind of sketches it in and assumes the inker is going to fix it, then looks like a goof when they don't.
On the inside, it looks like Keith Pollard has drawn him with a Beretta M12.