Eight Mistakes Buyers Make With .22 LR and Big-Bore Rifle Ammunition

Eight common mistakes with .22 LR and big-bore ammunition, from mixing look-alike .458s to feeding a semi-automatic the wrong rimfire load.

Big cartridges invite big mistakes, mostly because many of them share a bullet diameter or a similar name, and even the humble .22 LR has its traps. These eight come up most often.

1. Mixing the .450s

The .450 Bushmaster, the .450 Marlin and the .450 Nitro Express are three different cartridges. The Bushmaster is a straight-wall AR-pattern cartridge with a .452-inch bullet, the Marlin a belted lever-gun cartridge, and the Nitro Express a rimmed double-rifle cartridge. Anyone who wants to buy 450 bushmaster ammo should check which one the rifle is marked for.

2. Mixing the .458s

The .458 Lott is a lengthened .458 Winchester Magnum. A rifle chambered for the Lott can also fire .458 Winchester Magnum cartridges, but a .458 Winchester Magnum rifle cannot chamber the longer Lott, and forcing it is dangerous. The Lott's loads are at 458 lott ammo. The .458 Winchester Magnum's lead round-nose loads are at 458 win mag lead round nose ammo.

3. Confusing the .458 SOCOM with the .458 HAM'R

The .458 HAM'R is built from the .458 SOCOM case with the shoulder moved forward, and it needs a larger, stronger AR-10-size bolt and barrel extension, so the two are not interchangeable. The .458 SOCOM's 300-grain loads are at 458 socom 300 grain ammo.

4. Feeding a semi-automatic very-low-velocity ammunition

Some very-low-velocity .22 LR loads, such as Aguila's Super Colibri, do not generate enough force to cycle most semi-automatic rifles, and they are meant for particular uses. Read the box before loading. Aguila's loads are at aguila 22lr ammo.

5. Assuming all .22 LR is the same

Standard-velocity, high-velocity, subsonic and match loads behave differently. Match ammunition, such as Lapua's, is chosen for consistency in competition rifles, and Lapua's loads are at lapua 22lr ammunition.

6. Treating the 5mm Remington Magnum as a .22 WMR

The 5mm Remington Rimfire Magnum is a bottlenecked rimfire with a .204-inch bullet and a larger rim than other rimfires. It fits only rifles chambered for it, such as the Remington 591 and 592, and its hollow-point loads are at 5mm remington magnum hollow point ammo.

7. Mistaking one nitro express for another

The .450 Nitro Express fires a .458-inch bullet and the .470 Nitro Express a .474-inch one, so they are not interchangeable, though both are rimmed double-rifle cartridges. The .450 Nitro Express's loads are at 450 nitro express ammo for sale. Hornady's .470 Nitro Express loads are at hornady 470 nitro express ammo.

8. Treating the .500 Auto Max as a .500 S&W

The .500 Auto Max is essentially a rimless .500 S&W Magnum, but it headspaces on the case mouth and is made for the AR500 rifle. It is not the revolver cartridge, and its loads are at 500 auto max ammo for sale.

General guidance only. Never fire a cartridge in a rifle that is not marked for it, and confirm the chambering, current stock and state shipping restrictions before ordering.