The gunsmith and the muzzle thread

You all know these film scenes: the hitman sits in his hotel room, opens his gun case and screws the silencer onto his long gun. He must have gone to the gunsmith beforehand, because he will have cut a suitable muzzle thread for it. How the story with the contract killer continues is of no interest to us at this point.

Instead we concentrate on the muzzle thread. In order to attach a silencer to the gun, a thread must be attached to the front part of the barrel. This thread must be exactly in line with the barrel bore axis for a perfect shot. When selecting the threads, one should first know the outer diameter of the barrel.

Ideally, the thread should be about 2 mm smaller than the outside diameter. For a 17 mm barrel, a 15 mm thread would be suitable. The thread should also have a small pitch so that the thread does not come off easily. Fine threads are suitable for this. With M15 we would have found the right thread type with M 15 x 1 with a pitch of 1. As a rule, European manufacturers also use the ISO fine thread, while in the USA the UN fine thread is used. For small caliber and airguns, UNF ½” with 20 threads per inch is used. The standard thread for US-American weapons up to cal. 6.5mm is UNEF ½”-28 threads. The standard thread for large caliber weapons is UNEF 5/8-24 speed.

Thread cutting should always be left to an expert. In this case, experienced gunsmiths are the contact persons. Or you can order the gun with a corresponding thread. Experts advise not to store the gun with the silencer screwed on and we advise to protect the thread with a nut if the silencer is not screwed on. Fine threads are very sensitive. Our hitman knows all this too and that is why he screws the silencer on his sniper rifle only before the perfect shot is fired. This has a M 18 x 1.5 mm muzzle thread.

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