1911 Barrel Fitting Question Part II

[schmeky]

I set up an old 1911 barrel in my mill and cut the rear hood extension, then squared up the sides of the hood. I then did a cut on the bottom lug. Everything turned out fine.

My question is the bottom barrel lug vertical area, referred to as the vertical impact surface (VIS). I understand the horizontal area of the lug is what both times the unlock sequence and raises the barrel into the slide locking lugs. It seems to me the VIS is a stopping/limiting mechanism. Correct?

Therefore, can someone tell me if the VIS acts mainly as a limiting factor to stop slide/barrel travel? As I understand it, when I begin trimming the lower barrel lug, I should stop metal removal when the manual saftey can be engaged into the slide recess. At this point no more metal should be removed from the VIS.

If I have lug drag present on the barrel/slide lugs, I would dress or lathe cut the barrel lugs until drag is no longer present, correct?

 

[krs]

Don't confuse the VIS with the lug surfaces that interact with the slide stop. The work of lockup is done by the latter.

That's your hint..run with it, but don't start to mill the vertical surfaces - those are not where your attention is needed just now.

Schmeky, I have to take my wife to the hospital now so won't be around.

Keep in mind the old carpenter's rule to measure twice, cut once. In this it means don't cut anything until you're absolutely sure that it needs cutting. You can't put it back.

 

[log man]

I set up an old 1911 barrel in my mill and cut the rear hood extension, then squared up the sides of the hood. I then did a cut on the bottom lug. Everything turned out fine.

If it was an old barrel, had the hood and lower lugs been welded up, so as to have enough material to get a tight fit? You can't just re-cut these areas and make an improvement if not. Unless some how there was too much material.

My question is the bottom barrel lug vertical area, referred to as the vertical impact surface (VIS). I understand the horizontal area of the lug is what both times the unlock sequence and raises the barrel into the slide locking lugs. It seems to me the VIS is a stopping/limiting mechanism. Correct?

First off the VIS is referring to the vertical surface in the frame that stops the barrels rearward movement at link down. The back of the lower barrel lug is what hits the VIS. The cam and stop of the lower lug feet is what hopefully rides the slide stop pin into battery, it does not time the barrels link down. The link should be as short as possible and still have a little looseness when the slide stop pin is against the feet at battery.

Therefore, can some tell me if the VIS acts mainly as a limiting factor to stop slide/barrel travel?

The barrels rearward motion is arrested by the VIS, the slides rearward motion is arrested by the frame abutment, which is what the guide rod head rests against.

As I understand it, when I begin trimming the lower barrel lug, I should stop metal removal when the manual saftey can me engaged into the slide recess. At this point no more metal should be removed from the VIS.

This is more or less correct assuming the slide is in spec., however it isn't the VIS as explained earlier.

If I have lug drag present on the barrel/slide lugs, I would dress or lathe cut the barrel lugs until drag is no longer present, correct?

Absolutely not, that would reduce upper barrel lug engagement, If you do not have at least .010" clearance at link down and the lower lug is hitting the VIS, not the bed then the VIS is moved back a few thousandths. If is stopping on the bed and not yet hitting the VIS then the bed needs lowering.

LOG

 

[schmeky]

If it was an old barrel, had the hood and lower lugs been welded up, so as to have enough material to get a tight fit? You can't just re-cut these areas and make an improvement if not. Unless some how there was too much material.

It's an old "practice" barrel, not the one being fitted.

First off the VIS is referring to the vertical surface in the frame that stops the barrels rearward movement at link down. The back of the lower barrel lug is what hits the VIS. The cam and stop of the lower lug feet is what hopefully rides the slide stop pin into battery, it does not time the barrels link down. The link should be as short as possible and still have a little looseness when the slide stop pin is against the feet at battery.

OK, got it.

Absolutely not, that would reduce upper barrel lug engagement, If you do not have at least .010" clearance at link down and the lower lug is hitting the VIS, not the bed then the VIS is moved back a few thousandths. If is stopping on the bed and not yet hitting the VIS then the bed needs lowering.

A huge leap in my learning curve. This is precisely what I was looking to understand better. Thanx a bunch.

I'm making a barrel centering set-up so I can start fitting the sides of the barrel hood, which is approximately .045" to wide on the new Kart match barrel. The hood is approximately .026" to long. The Kart barrel has more material on one side of the barrel hood than the other for fitting; I need to ensure I have the barrel centered in the slide before I start cutting.

Appreciate the help.

 

[krs]

Schmeky,

Kart makes a little kit of tools to assist in correctly installing a new barrel. Part of the kit is a notched block which fits to the lower lugs so that those lugs can be held square to the slide while determining how much and where to cut the the hood.
It's not perfectly accurate but it's more than adequate for that part of the job.

If somewhere you can find a picture of the thingy you could easily make your own. Their kit, which I think also includes a single .003" feeler, a sort of sloppy but easy to use substitute bushing, the gizmo above, and best of all a little booklet of instructions called "New Math for barrel installers" or something like that. I've only looked their kit over at a friend's and remember thinking that I sure could have used it 35 years ago. I think it's about $30., probably Brownell's if anyone sells it.

 

[schmeky]

Krs,

Thanx for the info. I may contact Kart if Brownell’s doesn’t have this.

I have a problem/question:

I have the sides of the barrel hood cut and the barrel will mortise into the slide fine. However, there is a rear barrel hood - slide gap of about .010” . The chamber face is hitting the slide breach. It “looks” as though the barrel chamber needs to the cut to allow the barrel to set back fully into the frame.

However, I am hesitant to go any further. Suggestions?

 

[log man]

The hood is short. It should be long enough so that the barrel is meshed and is held forward as far as possible and still go in and out of upper engagement.

LOG

 

[krs]

I'm not sure if your description merits this bad news, Schmeky, but you'll want to be aware of it in any case.

Your usage "The chamber face is hitting the slide breach" is unclear to me as to meaning since to me the chamber face and the breech are the same thing. Do you mean that the CARTRIDGE head (face) is contacting the slide breechface?

If so this may be your reason: Not all replacement barrels, not even the barrels sold as "drop-in", are necessarily chambered completely. In a rifle it's known as a short chambered barrel with the chamber shipped between .010" and .050" short of correct headspace in a given installation. The determination of, and final headspacing of the chamber is left to the gunsmith who installs the barrel.

What is your distance from the rear face of the rear slide upper lug to the breechface? It should be the same or smaller (by only a very few thousanths) than the distance between the rear of your barrel hood and the rear face of the rear barrel upper lug. Is this starting to sound like an obsessive attention to 'rears'? Well.....yeah. (some leave a fairly liberal clearance there as it's got less to do with accuracy than the fit of the sides of the barrel hood, and you've got to have SOME room there if you hope to go to battery) If these are good then you've finished with your barrel hood. If you now have cartridge contact to the slide breechface and a tight fit or refusal of the loaded chamber barrel to fully rise to battery then I think you must need a bit of chamber reaming. The bad news part is that them reamers ain't cheap (seems like I paid $74. for the last Clymer .45 I bought but that was quite a few years ago. (There's a place that rents them - I'll try to find the link to them if they're still in business)

http://www.4-dproducts.com/index.php


EGW is making a kinda' neat little guage for the measuring I spoke of....http://egw-guns.com/store/index.php?main_page=product_info&cPath=38&products_id=50

 

[log man]

The chamber face is the barrel at the chamber end and is hitting the breech face blocks, ideally the hood should be what contacts the breech face.

LOG

 

[krs]

It's still the 'old 1911 barrel' in the original post, we hope.

Log, is "breech face blocks" a GI or engineering terminology for those areas alongside the breechface? If so I must have missed it. I've never used any descriptive term for them, in fact don't remember having had a cause to discuss them before this one.

 

[log man]

Well where did I first learn that is what they where called....hhmmmm can't remember, breech guide blocks would be a bit more descriptive and correct, the side of the left one is referred to as the tensioning wall as the extractor tensions the case head against it. Would be nice to have a pictorial with correct or at least acceptable names for all the parts surfaces. Like the disconnector, there's the top or head the square hole, the angle or wedge, which is it, the ears, kinda be nice to be on the same page.

LOG

 

[krs]

You've got me going a little. I have complete U.S. Army Armament Research and development Command drawings, Dept. of the Army Rock Island Arsenal drawings, Springfield Armory Ordnance Corp, Department of the Army, and a large number of otherwise sourced copies of original drawings for both 1911 and 1911a1 and so far haven't fouund a nomenclature marking to describe those areas. It's kinda' like "why name the inside of the slide? It's the inside of the slide."

I'll let you know if I find something, but right now it's dinnertime and I don't miss that for some silly researching.

 

[schmeky]

Gentlemen,

I need to take a pic. The throat, or sides of the throat, was contacting the "sides" of the slide breech face. This was with a gap between the barrel hood and slide breech. I eventually had to cut about .010" off both sides of the barrel throat.

I now have the barrel and slide lugs linking up, but I do not have 100% lug engagement. I have a lug file on order from Brownell's (along with a lug cutter). Firing pin contact is high on a primer and lowering the lugs should bring the firing pin contact closer to center.

This is my first, so it's going very slow, but I'm learning.

 

[krs]

Hi Schmeky!

Yeah, a photo would be good. Your:

"I eventually had to cut about .010" off both sides of the barrel throat."

is a little worrisome because you're trimming at the cartridge's support when chambered. Ten thousandths probably won't cause a loss of life but it's not a good way to solve a hood fitting problem.

If you're able to do tig or acetyline welding, a small bead around the hood would allow for a new more precise fitting of your barrel.

 

[log man]

Taking material off of the barrel chamber faces when the upper lugs are already engaged is counter productive. The hood should be what holds the barrel as far forward as possible in the slide when the upper lugs are just able to engage. Taking material off of the barrel face will just let the barrel slip further back. Now when the gun is fired, the barrel will slam forward in the slide as it is pulling back until the barrel lug faces contact the slides lug recess faces. All that movement isn't good. Remember that head space is the dimension from the breech face to the chamber shoulder when the barrel is as far forward in the slide is it can go. With the barrel cut as you've described it the case will be visible at the hood and sides. Maybe in somebody's Ransom rest with a long cord to pull the trigger.

LOG

 

[schmeky]

Taking material off of the barrel chamber faces when the upper lugs are already engaged is counter productive.

This is not the case. There was a small gap, about .002-.003" between the barrel hood and the slide breech. The barrel chamber throat sides were contacting the slide, arresting any further rearward movement of the barrel. This is W/O the lugs ever engaging.

I'll post a pic in the morning that should provide clarity. I may have screwed up, a distinct possiblity.

 

[log man]

Okay, great, carry on, you've done the right thing me thinks!

LOG

 

[schmeky]

The pen points to the areas that are in contact with the slide breech face. These are the areas I had to cut down about .010" to acheive proper lug engagement. With a factory cartridge in the barrel, there appears to be full case support, however, I still have to cut and blend a wadcutter fed-ramp. Additionally, it appears as though the head space is ideal.

I still have slight contact with the breech face, I estimate removing about .001" would alleviate this (area the pen points to). This means I am headspacing off the barrel presently, correct? I have never read anything about having to remove material from the barrel chamber face to fit a match barrel. Presently, the lockup is bank vault tight with no horizontal play in the barrel whatsoever.

Am I on the right track? What have I done wrong?

 

[log man]

I wouldn't say you've done anything wrong at this point. With a loose bushing can you push the barrel all the way up into the upper lugs and if so how much room is there between the breech face and the end of the hood, or is the hood now touching the breech face. If the barrel face is still what's keeping the barrel from going all the way up then take the high spots down. With the firing pin and extractor out put a deprimed resized case in the chamber and with the barrel pushed up so you can see your firing pin alignment.

LOG

 

[schmeky]

Log,

I have lug engagement, but it's not 100% vertical. I have already checked the firing pin contact and it's high presently. The slide lugs are contacting the 1st barrel lug at the 10 and 2 O 'clock positions, so I have to start working the barrel lugs with a lug file (should have the file Wednesday) and watch for 100% lug engagement, and at the same time keep an eye on the firing pin strike.

The barrel hood is just touching the breech face presently, in fact there is contact on the areas in the picture and the barrel hood presently, but most of it is in the barrel face.

If you look at the pic and use the feed ramp as a reference, you can see how much I had to cut the barrel face. The feed ramp originally extended to the bottom of the barrel face.

 

[log man]

How does the barrel ramp look when the barrel is in the frame and pushed back against the VIS? Since the hood is actually in contact with the breech face you could take just a bit more off the chamber face where it's hitting, you might clean up the face of the breech blocks also which will help gain a thou or two.

LOG

 

[schmeky]

How does the barrel ramp look when the barrel is in the frame and pushed back against the VIS?

Excellent question. I just checked it and with the barrel firmly seated in the VIS the barrel ramp is approximately flush with the frame feed ramp. I know I need .030" here eventually.

 

[log man]

The .030" isn't written in stone and as long as it's flush and the barrel ramp it self is extended down to more resemble before it may work fine. I asked Fred about that very thing in regards to the 9mm and he said the frame ramp to barrel should be from nothing to something, and chuckled and went on to say when it works it's good.

LOG

 

[schmeky]

Log,

My "thanx" for your help so far seems inadequate. I really want to thank you for your input. This barrel fitting is really an art if done well (I'm definitely not there yet).

I'm not quitin' til' it shoots right.

 

[krs]

There's something all wrong here.