M
- M&P 15-22 (Smith & Wesson rifle)
- M&P 15-22 Sport (Smith & Wesson rifle)
- M97 (Winchester shotgun)
- mainspring
- Mann barrel
- Mark II (Ruger pistol)
- Mark III (Ruger pistol)
- Mark 4 (Leupold scope)
- Mark IV (Ruger pistol)
- Marlin Model 80 (rifle)
- measurement, barrel
- metal cased bullet
- Mikhail Kalashnikov
- Mini Infidel (Benchmade knife)
- Model 10 (Savage rifle)
- Model 12 (Remington rifle)
- Model 12 (Winchester shotgun)
- Model 32 (Remington O/U shotgun)
- Model 37 (Ithaca shotgun)
- Model 40X (Remington model, Rangemaster)
- Model 40XB (Remington model)
- Model 40XR (Remington model)
- Model 70 (Beretta pistol)
- Model 70 (VZOR/ČZ pistol)
- Model 74 (Winchester rifle)
- Model 80 (Marlin rifle)
- Model 88 (Winchester rifle)
- Model 97 (Winchester shotgun)
- Model 99 (Savage rifle)
- Model 121 (Remington rifle, Fieldmaster)
- Model 510-X (Remington rifle)
- Model 511-X (Remington rifle)
- Model 512 Gold Wing (Stevens O/U shotgun)
- Model 512-X (Remington rifle)
- Model 513 (Remington rifle)
- Model 550 (Remington rifle)
- Model 550-1 (Remington rifle)
- Model 550-1A (Remington rifle)
- Model 550-2G Gallery Special (Remington rifle)
- Model 550-A (Remington rifle)
- Model 642 (Smith & Wesson revolver)
- Model 700 (Remington rifle)
- Model 740 (Remington rifle)
- Model 742 (Remington rifle)
- Model 760 GameMaster (Remington rifle)
- Model A303 (Beretta shotgun)
- Model 1897 (Winchester shotgun)
- Mohawk 48 (Remington shotgun)
- Mountain Eagle .22LR (Magnum Research pistol)
- MP34 (Steyr-Solothurn submachine gun)