first off the rifle models in the game are based off of the M16A2 or A4 variant, its possible its an A3, but i dont believe it has a removable carry handle, all thoe its hard for me to tell with the low quality of the gun model. But is its a new generation of M16/AR15, its not a viatnam era rifle, so you can be sure its one of the three variants.
The other rifle in the game is modeled after the Heckler and Koch (H&K) G36, not an AG36. An AG36 is a Heckler and Koch 40mm grenade launcher designed to fit the G36 and G36K rifle. There is a very big difference between AG36 and G36.
G36
AG36
As for the handgun models in game, there are 6 models, one for the redpill speical, one for the royer snub pistols, one for the lancet and harlick arms pistols, and one for the FM700, and one for the westeks and FM900's, and finally the musket pistol that fires the silver bullet.
the harlkick arms, redpill special, and royer snubs its hard to tell what gun in specific they're modeled after because of the wide variety of revolvers that are all very similar looking. My guess is that the lancet/harlick arms were probably modeled after a 6" Colt Python, but again its hard to be sure exactly because of the wide variety of revolvers there are, so your guess is as good as mine.
The FM700 was directly modeled after the IMI Desert Eagle and there is no mistaking the design and look of this handgun.
The westeks and FM900's... well this can be a hard one to figure out. When looking at the design of the gun, when you look at the front end of the slide and lower frame, one could easily confuse it for a H&K USP variant by the shape of the slide and the accessory rail. And at the same time the thumb grove and the the accessory rail on the frame could lead thoes who dont know much about guns to think it might be a comon glock. But its neither, the gun is based off of a off of a Smith & Wesson / Walther P99, the same gun used in the newer james bond movies.
Screen shot of the gun in game.
Photo of a P99
And for thoes who think it might be a glock, photo of a railed glock 20
When you compair the photo's, pay attention to the detail on the grip placement of the the slide release and mag release, you will see a huge difference.
onto the SMG's...
There are two models for the SMG's in the game, you have the FM11-Zatkin model, and the FM9-w/e model.
The Zatkin/FM11 is based off of one of two guns, a Mac 10, or a Mac 11. Based on the size of the gun in game Im going to assume the gun that is in game is modeled after the Mac 10 and not the Mac 11. The difference between the Mac 10 and the 11 is the Mac 10 fires a .45 caliber ACP bullet and has a slightly larger frame than the Mac 11 that only fires a 9mm round.
Mac10
The other SMG model in the game is the FM9, the gun has a very destinctive design that is not mistakable with any other gun design and thats the H&K MP7. While the model in game isnt quite in proportion, thats the gun its modeled after.
MP7
As for the shotgun models in game, you've got the aprin/mp700 and stinger model
The aprin/mp700 its hard to tell exactly what it is modeled after due to the wide nature of pump action shotguns, a fair guess might be a Remington 870 sawed off with an extended magazine tube. But again thats only a guess, its hard to say.
The Stinger model is based with no question off the Spas 12, 12 guage shotgun
spas12
I think that covers most of the gun models in game, if not, a large portion.
To conclude this post, I will say this, and sorry if I sound like a *bleep* for saying it, but before you post speculations or guesses as to the specifics of any given topic, do the research to make sure your right, or label your guess and speculations as such that way it wont confuse people people and they wont assume it to be fact, and pass bad intel off to other people.