Who are the most famous Manufactures?

Remmington and Winchester.

What are the popluar calibers?

10mm, 25 Auto, 32 Auto, 357 Mag, 357 Sig, 38 Special, 380 Auto, 40 S&W, 41, 44 Mag, 45 ACP, 45 Long Colt, 5.7x28mm, 9mm