The 37mm is manually loaded weapon, but was capable or fairly high-angle fire (I think something like 60deg). ROF should be somewhere around 25rpm. Don't expect to take down many planes with this one. The M2 is your better bet.
37mm fires HE and AP, or APBCR. Could likely take AA guns, Osties and M16/M3's. Can take a PzIV from the rear or very close in the sides (the PzIV wasn't well armored for '44/45, with 50-80mm in the turret and front).
Armor is thin, mostly around 16mm.
It was, and will probably act like, armored cav.
Thog