The pistol is exactly like all other P22s with exception of the red locktited on barrel nut which has no wrench lands. You can get a regular barrel nut from Ft Smith. To remove the one you have you can file some wrench lands ( flat spots ) so a wrench will fit and then heat it and immediately remove with a wrench. You can also heat it and get it off with pliers but you will scratch up the finish if that bothers you. Wouldn't bother me. You might also wrap the heated nut with thin leather to try to protect it but do it while the glue is hot. Not red hot, just heated to soften it. All P22 barrels are threaded...even CA models....the only difference is the barrel nut. You will need to purchase a thread adapter to screw onto the end of the barrel to which you will screw on the suppressor.. 1917
Thread adapter fitted to a stock P22 barrel. You will need to replace the barrel nut with one of these.