The most prominent weapon in the film, the Spectre M4 SMG is carried by Valkenvania Police Chief Constable Dennis Valkenheiser (John Candy), and used by Constable 'Miss Purdah' (Valri Bromfield). The Spectres in the film do not have foregrips nor the folding stocks.
An interesting note, the semiautomatic-only version of the Spectre has no foregrip or folding stock, like the weapons in the film. However, the Spectre fired by Miss Purdah in the film is fully-automatic. As such, these guns could very well be either full-auto versions that simply have the foregrips and folding stocks removed, or perhaps semi-auto versions (with the firing gun simply being one converted to full-auto).
What appears best to be a Smith & Wesson 639 pistol is carried by Miss Purdah in one of her dual reverse-draw holsters - Best seen in the larger shot of when she aims her CAR-15 alongside her vehicle.
Error creating thumbnail: File missingSmith & Wesson 639, early model - 9x19mmError creating thumbnail: File missingMiss Purdah has a S&W 639 pistol in her left-side reverse-draw holster (The closer one shown) as she aims her CAR-15. Though difficult to tell, the pistol appears to have a slightly rounded backstrap, unlike the 659 and 645, which are straight.
Beretta 92FS Inox
The pistol in Miss Purdah's other holster best appears to be a Beretta 92FS Inox.
Alvin Valkenheiser's (Dan Aykroyd) personal weapon appears to be a stainless Walther PPK pistol. Chris Thorne (Chevy Chase) very briefly handles this weapon. The PPK in this film appears to have engraving on the slide and Ivory grips.
During a stop, an inebriated thug named Arthur (Daniel Baldwin) pulls a nickel-plated snub-nosed Colt Python on Dennis (John Candy), though it gets quickly knocked out of his hand. It is seen again a bit later on the desk of Judge Alvin Valkenheiser (Dan Aykroyd). A New Jersey State Trooper at the end of the film also wields a full-sized blued-steel Python.
As Judge Alvin Valkenheiser examines the confiscated items, including the Colt Python Snub shown above, a Beretta 92F semi-auto pistol can be seen on the desk.
Interestingly enough, later in the film, Miss Purdah carries what appears to be an actual XM177E2 carbine, most likely standing in for the CAR-15 shown earlier. Like the CAR-15, it is never seen actually being fired, so it's likely this weapon may be a dummy gun or other non-firing prop. It is a very close looking example, in any case.
Error creating thumbnail: File missingXM177E2 Carbine aka Colt Model 629 - 5.56x45mm. This was the last variant of the XM177 rifle used in the Vietnam War.Error creating thumbnail: File missing"Right this way, Mr. Snappy-Comeback." Miss Purdah wields an XM177E2 (or at least, an awfully close lookalike) as she orders Chris to leave the room.Error creating thumbnail: File missingThe XM177E2 is seen slung on Miss Purdah's back. Note the grenade ring/notch before the flash hider, and the somewhat short and thick flash hider itself.
Ruger Mini-14 GB Stainless
Constable Miss Purdah (Valri Bromfield) carries and fires a Ruger Mini-14 GB rifle with scope and stainless barrel/receiver later on in the film as she chases after Chris (Chevy Chase) and Diane (Demi Moore).
Error creating thumbnail: File missingStainless Steel Ruger AC556 Carbine with Full Stock - 5.56x45mm. The AC556 is the militarized selective-fire version of the standard Mini-14, with a distinctive barrel with flash hider and bayonet lug. Ruger's Mini-14 GB ("Government Barrel") Model is the exact same weapon, but semiautomatic only.Error creating thumbnail: File missingMiss Purdah fires the Mini-14 GB. Note the bayonet lug and flash pattern.Error creating thumbnail: File missingMiss Purdah fires the Mini-14. Note stainless barrel and receiver.
M16A1
National Guardsmen accompanying the New Jersey State Troopers near the end of the film are armed with M16A1 Rifles with 20-round magazines.