[Apache6]

I think the guns use by both militia and maruader and/or freedom fighter groups in Continental US (CONUS is standard abbreviation) would be very different from the mostly handguns used by common criminals. Most CONUS marauders would have a pistol (or two) as backups, but their main weapon is much more likely going to be a longarm.

Common criminals use handguns because they are concealable. Long arms are MUCH more effective in actually fighting. Shotguns (pumps and semi-autos) will be very common. A wide range of semi auto rifles (AR-15s, Ak-47s, Mini-14s, SKSs, M-1 garands, M-1 carbines...) would also be common. Bolt action (and a lesser extent pump action and/or lever action rifles would be common among civilians, but unlikely to be used by fighting groups, except for scoped bolt action rifles for long range work.

Mr Pipes stated that "Larger caliber weapons (7.62mm NATO, 30-06, 8mm, etc) would be rarer though." I disaggree, 7.62mm NATO is the same as the .308 winchester round, which is one of the most common deer hunting rounds in the US. The 30-06 is also a common hunting round, and there are a lot of surplus 30-06s out there. Many of these rifles would be equipped with good telescopic sights that would make them into good long range rifles, not neccassarily "sniper rifles" but close in many regards. The remington M-700 rifle is very common hunting rifle, it's also what the USMC's M-40 sniper rifle was based on.

I think that "STEN" gun like SMGs would be very common. They are very easily built. I think many organizations might put them into production and use them to arm their 'troops' or as trading stock. In CONUS I'd expect to see them both in 9mm and .45 (being effectively a M-3 grease gun).

I think many mechanics could build a 'gatling gun' type weapon, and that a battery powered gatling guns in a range of calibers might be a fairly common support weapon.

There are a lot of civil war cannons used as display pieces. Munitions for these could be produced fairly easily. They are not useful against a military threat, but might be an intimidation weapon.

Similiarly I'd expect that a lot of militias and warlords...., would build some types of guntrucks and/or armored cars, and/or field expedient armored vehicles using bulldozers.... Do a google search for killdozer for an example of what a single guy was able to build in a garage.