https://m.youtube.com/watch?v=i3CqISdXdCA
If u can't find the length of barrel in handbook or on line, take the old one out and measure it. Providing you want the same length of barrel (ie u don't want to extend it into a mock silence) u should be able to just but one the same length but with a tighter bore. How tight is upto u and dependent on how good the ammo that u use is.