1911 verticle lock up question

[fortdick]

I am building my first 1911. I have a Caspain slide and an Ed Brown "drop in match barrel", which is not really drop in, but close. I am trying to fit the hood to the breech and want to make sure I don't cut it too far. I have the hood length to .001 of the distance from the breech face rear upper lug on the slide. The lug to breech measurement is 1.321 and the hood length is 1.310.

The barrel locks vertically with a slight click, but I only get about .020 lockup. Measuring the lug slots in the slide, the front slot measures .580 deep, while the rear slot measures .575. The lugs on the barrel measure .565 on the front lug and .580 on the rear lug, both measured from the depth of the front barrel lug slot. The second barrel lug slot (back towards the hood) is about .050 shallower than the first slot.


Before I go hacking way at the read lug slot on the barrel, I want to make sure that I am on track here. I believe if I file away about .025 of the excess height in the second lug slot I will get the lockup I need. I don't think my hood is too short because I do get some lockup, just not near enough. I have tried marking the lugs with a sharpie and even tried putty and all confirm I am not locking up deep enough.

Am I on track here or about to mess up my barrel?

Thanks for your advice.

Dan

[tr6guns]

Don't know where you are getting your measurements but go to page 11 of 16 and it will show the proper ones..
Also are you measuring with the gun completely together? If you are you might need a longer link..

[fortdick]

The pistol is not assembled. I am just fitting the barrel to the slide. The measurements are those specified in Kuhnhausen's book.

[Limited-Ten]

You must be postive that the hood of your barrel is not binding in the slide preventing further lockup. If the hood is not showing contact and the barrel recesses show hard contact with the slide, then you can carefully begin trimming the barrel recess. .020 is quite a bit lower than I would expect with a properly fit hood.

As you increase lockup you may need to shorten the hood as well.

[ar15barrels]

For additional points of view on this, also read the Kart "new math for shooters" instructions.
That little 0.003" pointed shim that Kart gives you in the toolkit is handy for watching hood side clearance as you drop the lugs deeper into engagement.

[ar15barrels]

The barrel locks vertically with a slight click, but I only get about .020 lockup.

Take another thousandth off the hood length at a time and see if the click goes away.

[fortdick]

You must be postive that the hood of your barrel is not binding in the slide preventing further lockup. If the hood is not showing contact and the barrel recesses show hard contact with the slide, then you can carefully begin trimming the barrel recess. .020 is quite a bit lower than I would expect with a properly fit hood.

As you increase lockup you may need to shorten the hood as well.

I gotta believe that the hood is not quite the right length. I measured the length from breech to the closest lug in the slide and used that for the first cut on the hood. Of course, I want it as tight as possible without binding and leaving me inadequate lock up. I am just trying to make sure before I start hacking away that the hood is the thing I need to cut.

This is my first fitting of a 1911 and I am trying to learn how to do it properly. I know a slightly short hood will still shoot, but shooting straight is my goal.

[eagershooter]

I found this on YouTube http://youtu.be/eTIpuOzS1o0

[umd]

I gotta believe that the hood is not quite the right length. I measured the length from breech to the closest lug in the slide and used that for the first cut on the hood. Of course, I want it as tight as possible without binding and leaving me inadequate lock up. I am just trying to make sure before I start hacking away that the hood is the thing I need to cut.

This is my first fitting of a 1911 and I am trying to learn how to do it properly. I know a slightly short hood will still shoot, but shooting straight is my goal.

I got that same barrel; it dropped in on the sarco slide but I had to fit the hood and the lugs to its final home in a wilson slide. Shaved off a bit of the hood and then had to fix the headspace. I didn't get the reamer in time for my last range trip so I have not shot it yet, but it properly locks up on the go gauge (and not on the no-go).

[bigcalidave]

Coat the whole thing with dykem and whack it with a hammer a few times.
Then you discover the areas it is really binding, and lightly file them smooth.

[fortdick]

Coat the whole thing with dykem and whack it with a hammer a few times.
Then you discover the areas it is really binding, and lightly file them smooth.

Okay, I will give it a try. Just hitting it with a hammer scares me. I have done that too many times trying to make things work.

[fortdick]

I found this on YouTube http://youtu.be/eTIpuOzS1o0

Thanks, I have watched it several times already and am trying to use his methods. Maybe I should watch again.

[ar15barrels]

Okay, I will give it a try. Just hitting it with a hammer scares me. I have done that too many times trying to make things work.

NYLON faced hammer!

['ol shooter]

The click is likely the edge of the barrel lug hitting the edge of the slide cutout as the slide and barrel go into battery. I like the dykem plan, use it on the barrel lugs and slide and see what you come up with. You can break the edges slightly if need be, it will not affect lock up. See Kuhnhausens books, I remember reading about the issue, I think it was there.

[fortdick]

NYLON faced hammer!

Okay, good tip.