Perry, Are you wanting to put a recoil spring guide rod at the back like a sgn-9ish build? The pps43 bolt will work in a tube if you cut the bolt slot correctly at an angle and remove the back side of the handle where it would protrude into the tube. If you're adding a guide rod for the AR15 spring and to add weight, you can pin it on like this one (a modified suomi bolt) for a sgn-9.
What all do you have in mind?
What all do you have in mind?