School me on muzzle threads

[gundoc]

The choice of threads is best selected according to the calibre so there is sufficient meat at the muzzle. The common sizes are: .22/223 - 1/2"x20 TPI (UNF) and 1/2"x28 (UNEF, AR15 etc). .243/6mm - same, .270/7mm - same or 9/16" UNF or 14x1mm, .30/7.62mm - 9/16"/14mm, .338" - 5/8" UNF or 16mm, and so on. The actual thread (Unified and Metric are both 60 degree vee) is of no consequence so long as it matches the suppressor. Aluminium suppressors are best with a coarser thread to avoid cross-threading.