Friday, February 5, 2016

Gun Skool, barrel lockup.

So, what, pray, is the very most critical areas to concentrate on when building a 1911 to get as good a lockup as possible?

Where the barrel hood touches the breechfaces, where the underlugs touches the slide release, and where the slide lugs engage the top lugs on the barrel.

What you want in the lugs in top of the barrel is have them contact the slide at two point at 10 o'clock and 2 o'clock.  I noticed that factory guns tend to contact at 12 o'clock only.  With this one central point of contact the gun can roll a bit.  It's relying on the barrel hood contact with the sides of the slide, and underlug contact with the slide release, to hold it in the same place.  

With the rebuilt gun we couldn't achieve 10 and 2 with the factory barrel.  We concentrated on the other areas.  With a new build with a new over sized barrel we get to fit the barrel to the slide and we get to shoot for really crisp lockup and at the 10 and 2 postition.

Like I said, good 10 and 2 and good underlug, and you are miles ahead of what I have seen with mulitple facotry guns.

That's what we did last class time.  We mark the barrel hood with magic marker and get the hood to fit into place until it just locks into the lugs by filing the spots where there is contact where you see marker removed.  Then we mark the barrel lugs and file on the barrel where it touchs at 10 and 2.  As we file we are also 'lifting' the barrel into position.   When I started the firing pin would strike a little above center on the primer.  I am trying to get it closer to center without going below center.  File too much away, move the strike point on the primer, and there is no fixing it.  Remove too much on the barrel hood and you can add metal with that area with a welder.  Same with the under lug.  But remove too much metal in the barrel lugs on top and you need a need a barrel. 

(Let me just add, let's say I was a really good gunsmith and made a pistol that could shot holes in an inch and half radius circle at 50 yards.  I, as a shooter, am not skilled enough to notice.  Chances are you the reader are not skilled enough.  Nor do you know anyone in person that is skilled enough.  Even famous competitive shooters you watch on Youtube, many of them are not skilled enough to notice 1.5" vs. 4".  It's still fun trying to make a gun that runs as well at a 9" gun in reliability, but shoots inside a half dollar.  Trying.  TRYING.) 

1 comment:

Old NFO said...

It's a challenge worth the effort... :-)