Fitting a bull barrel?

[Benevolence]

Hi all,

 

I’m working on fitting a kkm threaded 355 bull barrel to a fusion slide and stuck at 0.034” locking lug engagement. The lug recess on the barrel and slides are on approximately 0.055” and I’ve got the hood fit. From looking at wear marks from fitting as well as looking online, it appears the barrel near the muzzle end needs fitting to allow it to engage more. Also, the barrel appears to engage the lower side of the slide more when locked up. 

 

My question is, do I remove material from the barrel upper or lower sections highlighted (poorly) with a sharpie (nevermind near the locking lug though), or from the lower surface of the slide that interfaces with the underside of the barrel. If the answer is the barrel, do I use a file or is a lathe necessary? I was thinking to use a dowel and sandpaper (320-1200 grit) to grind down the lower barrel support section of the slide near the muzzle. 

 

I’ve done a kart ez bushing barrel and it was somewhat painless. The guy at kkm said just to remove material from the lug recess but that is not the limiting feature it appears. 

Edited June 19, 2020 by Benevolence

[mach1soldier]

Take a tiny bit off the top forward portion where it is hitting. It will allow the barrel to rise more. It shouldn’t take much.

 

usually you can mark the whole barrel and put it into slide. Whack underside a few times with rubber or soft mallet. Should show you exactly where to take material. 

Edited June 19, 2020 by mach1soldier

[digi531]

Hello, few questions first.  What is the barrel O.D. before threaded area usually .693 - .694 and measure inside diameter of slide bore, is it close to .699 - .700 ?   Did you polish the inside of the slide bore to remove any rough or high spots ?  Also, you didn't mention if you removed any material from the barrel locking lug recess, especially the first ( closest to the chamber ).  You need to mark those recesses right to the sides and see if it's hitting.  If it is you may see bright shiny marks especially on the sides of the barrel lug recess area which may prevent upward movement.  Once the barrel begins to move upward you will get light marks on the TOP of the barrel lug recess ( closest to chamber) where you must file ( lightly ) to allow upward movement and more barrel / slide lug engagement.  Go slow with that filing, a little goes a long way.  And, sometimes will bull barrels the very top about 3/4 to an inch back from muzzle area may be hitting inside the slide, mark this area and look for that bright shiny mark.  If there remove lightly with a file, stone or even shoeshine the spot with 300 - 400 grit paper.  Sorry for the long winded reply but bull barrels can be tricky and some brands are easier than others to fit.  Be patient and go slow.  Use a new piece of brass in the chamber and look through the slide firing pin hole.  Your looking for a nice round and  centered hole to tell you the barrel is high enough.  Good luck.