When you value something, you spend it more wisely. You should already know how perks affect guns and in what way. Rifled barrel, braced frame etc. The only things you would even need to test is anything that affects recoil as they change the pattern of it. Stop spending parts on useless nodes. If it didn't roll with anything remotely good for end game or pvp, scrap and move on. Pro tip: GOOGLE. Odds are someone has already gotten your gun with your perks and done the testing.