The .223 Remington or 5.56x45 NATO (or similar intermediate calibers) come in 20 or 30 round types as standard. Magazines can be aluminum, steel, or polymer. Greater or lesser capacities are available.
Pistol calibers and capacities are all over the map due to frame size and whether the frame is a single column or double column feed.
Saiga shotguns are modified AKs and take box magazines or drums of differing capacities and gages.
Thank you. Beretta 9 fs, 30 rnd. steel .223.
By the way, I’m soon putting an ad in the paper to sell all of my guns - private sale only. I do a lot of boating and figure I might as well not tempt fate.