I believe that 1/2x28”is the American standard for .22 and .223 barrel threading and the standard for most rimfire suppressors in the USA. 1/2x20” is a European standard for the same thing. Being European, many CZ barrels come in 1/2x20” threading and would NOT thread on to an American suppressor without an adapter. Some CZ’s now come with 1/2x28” threading for the American market. The barrel thread for any particular CZ barrel is usually stamped on the left side near the breach and also on the serial number sticker on the end of the box that the rifle ships in.

 

that's what i'm trying to decipher before i order the barrel.

Big Ed

 

They are 1/2x28

Chad