Thread pitch matcher
1/2×28 and 1/2×20 look identical in a photograph and will happily start onto each other before they bind. Pick what is on your barrel and what is on your can, and find out whether you need an adapter, a different barrel, or nothing at all.
What you have
If you do not know your barrel thread, do not guess it from the listing. Thread pitch gauges cost very little, and a mismatched thread forced onto a suppressor ruins a part you waited months to take home.
Compatibility
What this checks, and what it can't
Two things: whether the threads physically mate, and whether the suppressor's bore is large enough for the bullet you intend to send through it. The second is a safety check and it overrides everything else on the page.
What it cannot tell you
- Mount system compatibility. Quick-detach systems are proprietary. A tri-lug, a HUB-standard rear thread and a brand-specific taper mount are all different problems and none of them are thread pitch.
- Minimum barrel length. Most suppressor manufacturers publish one, and a short barrel with a fast powder can exceed the pressure the can is built for.
- Pressure rating. A can rated for .308 is not automatically rated for .300 Win Mag, even though the bullet fits.
- Concentricity. A crooked thread will let a can mount and still produce a baffle strike. That is a gunsmith's problem, not a calculator's.
- Full-auto or rapid-fire ratings. Entirely separate.
A threaded muzzle does not by itself establish that a suppressor fits. Confirm the complete combination with the suppressor manufacturer before you mount anything.