If your looking for 5/8X24 threads on your barrel, I don't believe your gonna get it at .615" diameter as 5/8ths (I would think) would require a minimum of .625" barrel diameter to get you there.
Now, I have a couple of 223 caliber rifles that I have had threaded that were thin at the muzzle and I was able to work both issues through the individual threading them and get them suppressed.
If you can accept .5X28 threading then continue reading, if you can't (due to your suppresor being 5/8X24) stop right here.
The first rifle I had done that was thin at the muzzle was a Remington Model 7 Youth model in .223.
The barrel diameter was large enough to thread .5X28 but was still too small to have the required shoulder available for the suppressor to "butt" up to and index upon.
As I was using an AAC M42K fast attach suppressor, I just had my guy thread the barrel "long" and have the suppressor mount index on the muzzle vice the barrel shoulder.
It was pretty easy and has worked for years and have never had a problem.
The other rifle was a CZ Model 527 that was nearly the same scenario, muzzle big enough to thread but no shoulder available to index upon AND the front sight needed to be removed and set back.
In this instance "long" threading was not going to work as the can I am going to use is a GEMTECH Titanium Trek and a shoulder is required (no indexing on the muzzle).
I called GEMTECH and asked them what the minimum shoulder requirement was for their TREK (I want to say .640 diameter was their min to provide a shoulder but I forget) and sent the rifle in to them and had them cut and thread it at a point that provided minimum shoulder for their can. Just so happens that was right at the 16 inch mark.
I have a third rifle with a thin muzzle that I'm eyeing with thoughts of suppressing, a Savage in .204 Ruger with a muzzle diameter of .550 inches.
I want to use the titanium trek but it wont work if I need .640 to shoulder it on.
I know that people who thread thin muzzle 22 rimfires will attach an adapter so the can can thread on and have a shoulder. I may have to give ADCO a call and see if that option will work for my .204.
