Llewelyn Moss (Josh Brolin) uses a 12 gauge Winchester Model 1897 sawn off pump for a large part of the film, and uses it to wound Anton. Winchester no longer makes this model, and those still in circulation are considered collector's items. The actual firearm used in the film was a clone of the Winchester 1897 made by Norinco.
A Heckler & Koch SP89 is picked up by Llewelyn Moss at the scene of a drug exchange gone wrong. If this film takes place in 1980, then the SP89 is anachronistic, since the gun was not manufactured until 1989. (The SP89 was obviously a lazy choice by the film's armorer, because the book clearly specifies a full-auto MP5K)
Sherrif Ed Tom Bell (Tommy Lee Jones) carries a Colt Series 70 Combat Government Model. This was the only model in that time frame that would have had black grips with the gold medallions, and combat style hammer. The Series 70 Combat Government Model was the forerunner to the Combat Elite.
Intra-Tec made Tec-9's in the 1980's, that's correct....but the before that the same basic gun was made by Interdynamics and sold as the KG-9 (open bolt) and the KG-99 (closed bolt)..so, it's not entirely a timeline problem
Norinco Type 56
Several Norinco Type 56 copies of the AK-47 assault rifle (both the fixed stock Type 56 and folding stock Type 56-1) can be seen on the ground next to dead drug dealers at the site of the failed exchange.
Anton Chigurh (Javier Bardem) uses a sound-suppressed Remington 11-87 Semi-Auto shotgun with a sawed off barrel in four shooting scenes in the movie.
(As with the TEC-9, this is also anachronistic because the Remington 11-87 was not designed until 1987 and the film takes place in 1980.)
Might be a Remington 1100. Which was in production at the time.
(At the same time, though there are suppressors designed for shotguns, the one fitted on Chigurh's 11-87 is much too small, and short to have a distinctive effect on the sound of the shotgun's blast. Real suppressors designed for shotguns are much longer, and even they don't manage to silence a shotgun's blast to the extent that the one in the film did.)
I think this might be a .410 shotgun based on the barrel size and bore size on the suppressor although the suppressor might just be small.
Llewelyn Moss (Josh Brolin) uses a Remington 700 when hunting a Pronghorn.
According to the novel [1], the rifle Llewelyn uses to hunt Pronghorn is a "heavy barreled .270 on a '98 Mauser action with a laminated stock of maple and walnut. It carried a Unertl telescopic sight of the same power as the binoculars [10x]". This description closely matches the Parker Hale 1200 series rifles [2], although the movie prop is most likely a Remington 700 variant, based on the appearance of the action and the placement of the safety switch.
Stock looks like that found on the VLS most likely .243 or 308.
When Anton Chigurh first goes to the trucks with the "mind riding bitch" guy, he executes both him and his partner with what appears to be a glock pistol. A Glock would also be an anachronism as they were not produced until 1983.
When Sheriff Ed Tom Bell and Deputy Wendell are checking out the drug deal gone bad. An Uzi is seen lying next to a drug dealer. (It may just be me, but I think it looks more like a Polish PM-63 RAK.
Chigurh seems to prefer to use a Captive Bolt Pistol on his victims when he can. The Captive Bolt Pistol is a pneumatic gun that fires a bolt into the brains of cattle to stun them before slaughter. Like the name suggests the bolt never entirely leaves the gun, it is shot out by air (or a blank) and then retracts back into the gun by return springs. Though not a "firearm" it is a gun and does play a big role in several scenes.