The shotgun is definitely an 870 folder, but the pistol is really not seen clearly (I'm not even sure how you can tell it's a Beretta at all). If it is a Beretta, it's probably a 92F, since the 92F is by far the most common Beretta in movies (actually, one of the most common handguns, period).

Here's the screen captures for my initial post.
"In the pilot episode, there's a scene in which Carmella confronts a would-be burglar outside her house with what looks like an AKM, which turns out to be Meadow rappelling down a wall. Is it an AKM?."

"In the episode "Denial, Anger, Acceptance", there's a scene in which Christopher fires 2 shots in the air when returning a truck that his friend Brendan stole from a trucking company under Uncle Junior's protection. It looks like a full-size Beretta semi-auto. The best view of it is when he fires it and the muzzle blast lights it up."

In the episode "Meadowlands", there's a scene in Jackie Aprile's hospital room when Christopher is telling Tony what happened to him and Brendan at the end of the previous episode. At some point he pulls out a semi-auto in frustration at his situation. It looks like a SiG-Sauer semi-auto pistol. I don't know if anybody can make out a model from these screens.

For the AK, I'm almost inclined to believe it is an actual AK-47 and not an AKM, but the gas ports on the barrel aren't easy to see. Maybe MT2008 or MPM2008 could help out on that matter.

The gun in the hospital appears to be a SIG-Sauer P226 based on the squared trigger guard.

The top of the AK's front sight seems to be broken off. I'd have to look at the receiver to be sure, but it seems to be either a genuine AK-47 (or a Poly Tech Legend copy), or a Type 56.

The SIG pistol is either a P220 or P226 (almost surely the latter, since the P226 is the common SIG in movies).

Thanks for the help guys, I'm updating the Sopranos page as I get more IDs.

Here's the third and last one from my original post.
"In "Meadowlands", when Tony arrives at Junior's restaurant to try to reach a compromise with him, he's seen checking his handgun before going in. It looks like a classic Smith & Wesson semi-auto. Looks like a long slide version."

I'd agree, it looks like a Smith & Wesson 39 or one of the older variants.

In the "I Dream Of Jeannie Cusamano" scene where Jimmy Altieri gets shot in the back of the head by Silvio for being an informant, Jimmy makes a failed attempt to retrieve his silver snub-nose revolver in his ankle holster. Can anybody make it out?

In the first episode of the third season a drunk Patsy Parisi is seen in Tony's backyard pointing a snub-nosed revolver at him. Any ideas what it is? Here are some screens.