>>12934264There are a couple of things you'd want to take into account if you sleeved the suppressor tube back over the barrel. Firstly, if it's centerfire, you will need a resilient blast baffle. The first baffle of a centerfire rifle suppressor gets eroded pretty quickly, and the best manufacturers make at least that baffle out of extremely strong materials, such as inconel and titanium.
Secondly, if you are going to use space around the barrel a la Reflex (pic related) or a la integral design, you need some method of taking advantage of that null space. The entire point of a suppressor is to provide space into which exhaust gas can vent, loiter and cool before escaping out the end.
To that end, your blast baffle (if center fire) or porting (if rimfire) need to direct exhaust gas into that space.
I wouldn't mess around with barrel porting if you don't know what you're doing, you can significantly affect accuracy, bullet stability and velocity if you do it wrong. It would be easier to make something like this Reflex design, using the blast baffle with a 30-50mm gap between the end of the barrel and the blast baffle.
Do keep in mind that whatever you manufacture, the baffles need to be as close to the diameter of the projectile as safely possible, with a margin for error, and the entire assembly needs to be EXTREMELY precisely threaded and mounted to the barrel. Depending on the difference in projectile diameter and baffle diameter, as little as one degree off center could cause baffle strikes, which are dangerous to the suppressor, the gun and you.
Also, as a simple word of caution, I would advise against building your own centerfire suppressor without knowledge of materials tensile strengths. It's a tremendous amount of pressure to contain, and nearly all major US manufacturers use permanently welded all-steel or inconel construction.
