I'm getting out of my Glock 21 and have a conversion barrel to sell. Lone Wolf 6" conversion barrel for the Glock 20 to 9mm. I also have the recoil spring and 1 10mm mag. I have used in both a Glock 20 and Glock 21 and it has worked well. The 9mm ammo fits in the 10mm mag which fits in either the 20 or 21. Has about 200 rounds through it - $85 This is the barrel http://www.lonewolfdist.com/Detail.aspx?PROD=623362 I'm sure there will be questions. Here is a thread from when I got the barrel https://www.northwestfirearms.com/threads/glock-20-9mm-conversion.155178/#post-1006735 Only interested in trades for glock 23/27 barrel to 9mm. Stripped billet upper for AR15, NiBO BCG for AR15, Seekins Precision BAR 15" hand guard, or .40/5.56/300blk ammo.