[JET55]

Hey all, looking for a little guidance. I've got a new NH recon frame with an EB slide on a new build. Slide is fit to the frame and I was working on the barrel (kart xact fit).

Hood is fit and I was working on the upper lug fit. I notice that the barrel is starting into battery, still have more to go. But the slide is short from being flush. I also see that the SS pin is not seating where it should be on the lower lugs, its just at the apex of going to the flat on the lug.

The SS pin hole is .445 from the rail and I think this is the reason the lower lug is not going over the SS pin. The SS pin is .200, hole .201. Everything else looks good.

Just for kicks I tried the barrel on two other 1911's and the slide/frame were lined up and the SS pin was hitting the lugs where it should be.

Not supposed to have to fit the Kart lower lugs but is this what I need to do? And wouldn't that require a shorter like at that point? There's only about .003 clearance between hood and alide when out of battery.

 

[Integrity Arms]

Sounds like your barrel link is too short now. Short link travel will produce the same issues your speaking of.. I've not used the exact fit, but I assume they come with a Number 3 link. maybe try a 4 or make the link bigger at the side opposite the lug feet. Pics would help kind of going in the blind sort of can be questionable.

 

[JET55]

That would take care of the barrel hood clearance, but then I would definitely have to redo the lower lugs. Or is it just a given at this point? I'm pretty sure that the SS pin hole distance to the rail is the reason for this. It's within tolerance, .450 (-.005) but the other two 1911's I tried the barrel on, in it's current state, both have exactly .450" from SS hole to rail.

And when I tried this barrel on the other two pistols the link size was perfect as the SS pin sat exactly where it should. I'm just leery of cutting the lugs on the kart barrel since they're supposed to be preset.

Edit: I figured I would ask kart since if anyone would know they should. They said that I shouldn't have to mess with the link or the lower lugs at all. That I should just keep going on the upper pads until the SS pin seats correctly on the lower lugs and the slide should even up with the frame. So here goes...

 

[BobRock]

If the engagement of the top barrel lugs is keeping the barrel from going fully into battery, then that's the place to work. You can be sure by bluing and checking. You can also put a little bit of modeling clay in the lug groove to see that it is smashed by the barrel lug.

You probably already know you're going for .040" - .045" of upper lug engagement (although I know of folks who like somewhat more).

 

[JET55]

When I talled to the guy at Kart he said he fits the upper lugs until he gets the correct contact on the lower lugs. He said he doesn't even check that measurement because if he gets the proper engagement below it will be right topside. Of course I am checking it as I go.

Oddly enough the Kart instructions pretty much state exactly what he said. That with everything in spec you should have proper upper engagement once you get the correct lower engagement, SS to lugs.

And, my progress so far is showing true to their statement. The slide is almost flush with the frame, the lower engagement is almost there and I'm right around .040" upper engagement. So I have no doubts now that its going to work.

Here's a nice tip for installation that I've discovered. They state a minimum of .003" clearance for the barrel hood sides. Initially set when the hood is fit to the slide. But, you should check this every time you put the blued upper lug/slide assy on the frame. If one side of the hood closes up that means the opposite sides upper lug needs to get filed down, it's too high. Being high it rolls the barrel causing the hood side tight fit and it will cause uneven lower lug contact to the SS pin. By constantly checking hood side clearance and relieving the upper lugs evenly I've been able to keep the barrel from twisting as it goes up, maintaining even lower lug contact. Kinda cool seeing it all work out.

 

[pistolwretch]

The guys at KART rock!
One needs to listen.....hard.

 

[JET55]

The guys at KART rock!
One needs to listen.....hard.

yes they do!

 

[JET55]

Upadte: it worked just like the instructions stated. Filed the pads and the SS went up on the lower lugs for good contact on the flat and front of the lug. On the SS I get 4 points of contact all the same, so its seating very nicely. Rear of slide is slightly back, but TS goes in and disco hole lines up with the channel. Wont blend that until I get a full function check completed. Looks gtg!