New barrel installed and a question,

[Jigballs]

Kart NM barrel and Colt contract slide .both new. Since i couldnt get an accurate measurement of the horizontal lug engagement i used a sharpie to highlight the barrels lugs and shot the pistol. Pistol shot great, 50 Rounds hard ball 1-2 inch groups ,barrel lugs didnt show any sign of deforming but the only contact marks were on the #2 lug on the barrel and minor at that . Whats confusing me is that i can see the #1 lug making contact when i hand cycle the slide but when i shoot it there were no marks in the sharpie ink .

I quess my question is , can the method marking the lugs with a sharpie and shooting the pistol or tapping on the barrel lower lug with a mallot give you an accurate reading of barrel lug contact with the slide lugs enough to allow adjusting/filing certain lugs ?

[niemi24s]

Have you read our Sticky, "Fitting A New Barrel"?

[Jigballs]

Have you read our Sticky, "Fitting A New Barrel"?


Yes . But i dont have a good way to measure the slide lugs to see how close i am with the barrel lugs. This is why im asking if i can use dykem or a sharpie on the barrel lugs to see which lug is making contact , then file that lug until the other lugs start to show contact marks. I though i read this somewhere but want to make sure im not missing anything.

[niemi24s]

Well, I guess if you don't have the slide lug measuring capability the method you mention is your only other choice. But, instead of marking the barrel lugs with a Sharpie (which needs a fair amount of applied force to rub off) you might try marking the barrel lugs with sight black or the soot from a candle flame.

Either will show contact with very little effort. It'll come off with just finger pressure. No need for a mallet or shooting the gun to show contact.

And while fitting, remember to keep close tabs on your dynamic headspace. Exceeding its limit can lead to excessive unsupported case length and possible case rupture - you don't ever want to have a case rupture on you! :scared:

Regards

[Jigballs]

Thanks for the tips on using the candle flame/sight black, reminds me of when i was i kid watching my dad blacken his M1 garand sights before a match, he used a little lamp similar to what miners wore on their helmets. I'll watch the headspace too, thanks

[niemi24s]

. . .he used a little lamp similar to what miners wore on their helmets.Ah yes, the carbide lamp. Used calcium carbide (in water) to generate the acetylene to burn. Miners could tell they were in an oxygen deficient atmosphere when the little flame went out. And when they were in an explosive atmosphere.....well, you can guess the rest!

[auto45]

But, instead of marking the barrel lugs with a Sharpie (which needs a fair amount of applied force to rub off)

I wondered about that. I just tried the sharpie on the VIS test, attempting to see if the barrel lugs hit and couldn't get any marks. Although, I can see the outline/marks of the bowtie on the barrel lugs, without any "coloring".

Have to try the sight black to see if I really do have a problem.

How about lipstick?

[niemi24s]

. . .couldn't get any marks.The Sharpie ink won't transfer to the other surface because it's dry.

If you want to mark one surface and have it show evidence of its contact on another surface then you need something like Prussian Blue, carbon paper or - lipstick.

The biggest problem with using the "one thing leaving a mark on the other thing" method is the applied thickness of the stuff doing the marking. It has to be thick enough to be visible after it gets transferred, but if it's too thick it can show contact where none exists (got transferred just because it filled the gap).

[auto45]

Okay, thanks Niemi24s.

Perhaps I'll try the lipstick first.