I just wanted to say the way the guns are previewed on this page is some of the slickest shit I've ever seen on itch.io. Very impressive, great job!!
Okay, the gun pedant in me can't resist adding this: what you've called an "M15" is actually an M16 or AR15 (the actual "M15 Rifle" is less well known and a variant of the M14) and your MP5 while otherwise pretty accurate is very rarely found or depicted with wooden furniture and should probably look like this:
Still, GREAT work!