Usually work with ships; love the idea of a small 20mm or 40mm cannon on the shelf – not necessarily a ship-oriented “close-up”.
If you want a Anti-Aircraft artillery piece, especially modern, there isn’t much out there. The M163A1 20mm Vulcan cannon mounted on a M113 chasis is about it. It is actually no longer in the active force, phased out in mid-'90s. Available from Italeri and Academy

Also the AvengerHMMWV ADA system by Italeri

There are a couple former Soviet systems in model form as well.
Dragon ZSU 23-4 Shilka
Eastern Express/ ICM/??(whoever owns the molds now) has a ZSU 23-2 towed AAA
kit as well.
Someone did make a Phalanx Close-In Weapons System in a large scale (1/32, I think)but I don’t have a link to it.
There are some kits for WWII AAA guns, but I am not sure which, not my area, I do mostly modern.
Do you mean arillery pieces? A slew of manufacturers have a German 20 mm Flak gun, either single or Tamiya makes the quad. Tamiya and Italeri make a German 37mm Flak gun as well. I’m not aware of any mainstream 40mm gun mounts. There are a some companies that make some AA mounted vehicles like a Whirblwind, Mobelwagen and some halftrack mounted AA guns.
For a beginner’s artillery piece, I would suggest a Tamiya PAK-40.
It’s usually available at Hobby Lobby stores, under $20.00, and not too many parts or figures to get bogged-down with.
For a beginner armor model, I would suggest a Tamiya M-3 Stuart.
Tom[C):-)]
A classic is the Tamiya 88mm flak gun as well.
Thanks everyone.
Went to a local hobby shop and bought the Tamiya 88mm – which, BTW, is quite nice.
Anyone have a good online reference for these things?
Hey join the ARtillary GB
Try this link:
http://www.wargamer.com/Hosted/Panzer/88mm.htm
Now you might have to go out and get a SdKfz 11 model for a towing tractor to go with it [:)]
Tom [C):-)]