The thread on your barrel decides which mount you need. These are the common ones in the US.
Always confirm your barrel's thread with the barrel maker or a thread gauge before mounting anything. A can mounted on the wrong thread, or off-center, can be hit by the bullet.
Common thread pitches
| Thread | Hand | Common on | Protonic |
|---|---|---|---|
| 1/2-28 | Right | .22 rimfire, 5.56/.223 AR-15s, most US 9mm pistol barrels | Proton Plinker; Gluon DT, Pion, Pion Fixed |
| 5/8-24 | Right | .30 cal rifles: .308 Win, .300 BLK, 6.5 Creedmoor | Gluon DT |
| M13.5×1 LH | Left | Many European 9mm pistols | Pion, Pion Fixed |
| M14×1 LH | Left | AK-pattern rifles in 7.62×39 | Gluon DT |
| 11/16-24 | Right | Big-bore lever guns and .45-70 rifles | Gluon DT |
| M24×1.5 | Right | AK-74-pattern rifles in 5.45×39 | — |
| .578-28 | Right | Many .45 ACP pistol barrels | Pion |
| 9/16-24 LH | Left | Many .40 S&W pistol barrels | Pion |
How to read a thread
Inch threads are written as diameter, then threads per inch: 1/2-28 is a half-inch thread with 28 threads per inch. Metric threads are written as diameter in millimetres, then pitch: M14×1 is 14 mm with 1 mm between threads. LH means left-hand: it tightens counter-clockwise.