What you experienced is why i buy mine instead of making one. There is a lot more to making a good suppressor than drilling out some pipe and installing some baffles.
Even some of the top manufactures do exactly what yours does. Poi shift is a common problem and the really good ones cost a lot of $$$.
To get aroumd that your going to need to learn engineering, physics, computer science, mathematics, and your going to need a very very good cnc machine. Cheaper to just buy a premade than diy when it comes to suppressors.
Suppressors are outwardly simple devices but have veryy very complex physics to get them to function well
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent