>>63967106
Beretta sells threaded barrels for around 160-200 dollars

For muzzle devices
>PMM
makes a decent one timed with shims like a rifle muzzle device.
>Jarvis
makes one where you need a flat on the threaded barrel for a set screw.
>Volkers Precision
Never looked into but I bet it’s a copy of the PMM.
>Beretta Comp
Never looked into.

If you’re looking into the Jarvis kit, you can get a threaded barrel and comp together for 440. They machine the barrel and comp sit perfect and add the flat to the threaded barrel for you, they also offer it in .575-40 threads which means the threaded portion is shorter so the comp port is closer and the overall package is shorter.

PMM on the left, Jarvis two port on the right