In current standard production, no.
32 short, 32 long, 32 ACP
The Tokarev and Mauser "broomhandle" pistols were made in that caliber.
There are only two types of firearms. Long guns and hand guns.
No such thing. You can have small caliber but not low caliber.
Some guns yes, but most guns would require gunsmithing to change caliber.
Pellet guns tend to come in two standard caliber sizes. The first smaller caliber is the most common for pellets guns and is .177 caliber. The second is .22 caliber that can be found on some higher powered pellet gun models.
7.62 mm (or 30 caliber) and 5.56 mm (or 223 caliber) are common rifle cartridges. Pistols, machine guns, and artillery will of course be different from these.
Strum Ruger made many 22 caliber hand guns. It would help if you Identified the model
The caliber
.68. Almost all guns are this caliber.
The 308 caliber guns are more expensive than 5.56 assault rifles.
A 40mm handgun would fire a bullet the size of a golf ball. No such critter. There IS a .40 caliber handgun (about 10mm). There are dozens of larger caliber handguns than .40 caliber. They include the .41, .44. .45, .455. .460, .475, .500- and several others.