They at just a bit long. The np02 barrels fit and have 1/2" thread ? a lad up the street has the one with 2 bottles fixed on the rifle he brought it down last week not shooting straight ... his shroud was only screwed on at the breech end no support bush on the barrel threads he knocked the shroud and kinked on the threads ended up taking it off put his silencer on the barrel and like a laser again.