When I decided to use a Glock handgun as my 9mm silencer platform, the issue of how best to go about getting a threaded barrel presented two solutions:
I could get an aftermarket threaded barrel and hope it worked.
I could get a Glock barrel threaded to my exact specifications.
I chose option 2 because I wanted to maintain that "Glock Look" with a factory black Glock barrel that I knew would fit and function to Glock specifications, and I could get the barrel threaded exactly for the silencer I would be using, instead of a one size [does not] fit all aftermarket barrel.
To thread a Glock barrel for a Glock 34 you need a Glock17L barrel.
The first issue is where to place the thread shoulder. The shoulder needs to be cut so that the silencer does not hit the slide or recoil guide at anytime during cycling. The good news is that on a Glock 34, due to the extended slide, the recoil guide is not an issue. So your shoulder needs to be just a little bit past the slide, as shown in this picture:
The measurement for where the shoulder should be is taken from the top of the breech to the shoulder as shown in this picture:
As you can see, mine is 5.4135 inches as shown on the caliper. In other words, 5.4 inches.
As for the threads, I chose to use 1/2x28, since that is common in the United States for 9mm handgun silencers, and was the threading of the silencer I was going to use (SWR/GS9K2). How long the threads should be is dependent upon the silencer you are using. You want the thread length to be equal to the length of the threads of the silencer. This way there is no overlap or underlap of threads, which would result in thread fouling from carbon buildup. Mine is just a little over .5 inches of threading as shown in the picture below:
These are the basic specifications I gave to the barrel threader. In addition to this, I had the threader thread to 2A, with less than 1/1000 runout, concentric to the bore, not the barrel. This is the end result:
How I threaded my Glock 17
