Fitting The 1911 Barrel Part 2: Bottom Lugs

Fitting The 1911 Barrel Part 2: Bottom Lugs

As we've noted before, the most important factor in 1911 accuracy is barrel fit. In the last article we fitted the hood, and in this one we delve into the fit of the bottom lugs to the slide stop. When the slide is in battery, the barrel should be wedged between the slide stop and the locking grooves in the slide with zero movement. In fact, if you function the pistol by hand without the recoil spring, you should feel a slight resistance as the barrel locks.

The lugs on our Kart barrel are oversized and must be cut to fit the slide stop. Fitting can be done by hand with files and stones (very time consuming), with a hand-turned lug cutter such as sold by Brownell's (080-000-068WB) or with machine tools.


I used a manual lug cutter for many years before I had a milling machine and they work fine, but there is no control over the size of cut. You get a .195" or .186" cutter and they have to work. I believe machining the lug with a dedicated fixture is the best way and that is how I do it now.



We begin by verifying the size of the slide stop pin. Check the size of the hole in the frame with pin gauges. The Colt frame I'm using for this demo is .202" and our new Ed Brown slide stop is .200". That fit is reasonable. Slide stops are available with pin diameters up to .203" for worn frames. Use the largest pin that will fit the frame and still rotate freely.

Install the barrel and Kart bench bushing in the slide and assemble it to the stripped frame without the slide stop. You will need pin gauges in sizes ranging from .180" to .200". Insert a .180" pin gauge in the slide stop hole and try to move the slide forward into battery.


If the barrel locks up on the pin, keep trying larger pins until you reach the largest size that will allow lockup. Let's say the largest pin the pistol accepts is .180". OK, that means you've got to remove .020" of material from the lugs for them to lock up on your .200" slide stop pin. Remove the barrel and take it over to the milling machine.


In our mill vise we have the Weigand barrel fitting fixture. This tool allows the barrel to be clamped in a V-block while the lugs are milled to size and the barrel can be removed for checking fit and returned to the fixture without loss of zero.

The bottom of the fixture has a step milled into it so cutting is done at the proper lockup angle. A digital readout is highly recommended when using this fixture. The cutter we have mounted in our mill collet is a four-flute HSS 5mm end mill (closest size available to our .200" slide stop diameter). Take a test cut, removing a few thousandths of material from the lugs.

Now we reassemble the slide, barrel and bushing to the frame and select the largest gauge pin that will allow the barrel to lock up, let's say .184" in this case.

An important check at this point is determining if both lugs are bearing on the pin equally. Blacken the .184" gauge pin with a marker, install it in the frame, function the slide a few times and remove it. Good contact by both lugs should be visible on the pin.

If not, adjust the jack screw under the barrel lugs on the Weigand fixture so the cut is slightly heavier on the lug that shows the most contact and take another test cut. Repeat this process as necessary to produce even contact by both lugs. When lug contact is correct, continue cutting until the lugs will lock up on a .196" or .197" pin.

Now, reduce your cuts to only .001î at a time until the barrel will lock on the slide stop with just a bit of thumb pressure applied to the rear of the slide. Finish fit with lapping compound and you should be done.

Judge the length of cut with the thumb safety when the barrel is locked up. It should easily enter the notch in the slide without a big gap at the front. If you are fitting the barrel to the original slide that came with the pistol, the rear edge should be even with the edge of the frame. If you are using a new slide, it may have to be dressed off after the barrel is fitted so there is no overhang.

Our barrel is not completely fitted yet. We still have to finish cut the chamber and install a bushing. Stay tuned for part 3.

Recommended for You

Please sign and share the petition to get the required 100,000 signatures by July 27. 2nd Amendment

Tell the White House that the 2nd Amendment Was Not Given to the People by Government

Firearms News - July 02, 2019

Please sign and share the petition to get the required 100,000 signatures by July 27.

CRKT makes 17 different knife models exclusively for Ruger, from fixed hunting knives to tactical folders, and many of their models are offered in several different styles. Accessories

Ruger CRKT Knives Review

James Tarr - July 08, 2019

CRKT makes 17 different knife models exclusively for Ruger, from fixed hunting knives to...

No one can restore receptivity to another Trump term with these disaffected gun owners but the president himself. 2nd Amendment

2020 is Trump's to Blow with Gun Owners

David Codrea - July 09, 2019

No one can restore receptivity to another Trump term with these disaffected gun owners but the...

See More Recommendations

Popular Videos

Performance Center M&P Shield M2.0

Performance Center M&P Shield M2.0

From Smith & Wesson, the M&P Shield M2.0 is a great option for a carry gun with optics option.

Kyle Lamb and Eric Poole talk SIG pistols

Kyle Lamb and Eric Poole talk SIG pistols

G&A Editor Eric Poole and Viking Tacticals's Kyle Lamb talks about 2 new pistols from SIG Sauer and a Lipsey's Special of the P365.

New handguns from Smith & Wesson

New handguns from Smith & Wesson

The Performance Center's M&P380 Shield EZ pistol features ported barrel, flat face trigger and tuned action.

See more Popular Videos

Trending Stories

Governor Northam is calling a special session of the General Assembly on Tuesday, July 9th, to do nothing but pass more gun control! 2nd Amendment

Virginia Governor Northam Declares War on Gun Owners

Virginia Citizens Defense League - July 09, 2019

Governor Northam is calling a special session of the General Assembly on Tuesday, July 9th, to...

Want the “Holy Grail” of AR-15 rifles? Brownells has made that possible with their BRN-Proto retro rifle. Rifles

Brownells BRN-Proto Retro Rifle

Patrick Sweeney - July 02, 2019

Want the “Holy Grail” of AR-15 rifles? Brownells has made that possible with their BRN-Proto...

A $50 Ring Loc-Kit gives AirForce Condor airgunners unparalleled power and accuracy. Air Guns

AirForce Airguns Condor Ring-Loc Kit Review

Tom Gaylord - May 29, 2019

A $50 Ring Loc-Kit gives AirForce Condor airgunners unparalleled power and accuracy.

See More Stories

More Handguns

Beretta brings back the Brigadier better than ever with the 92X Performance! Handguns

Beretta 92X Performance Unveiled

Jim Grant - March 21, 2019

Beretta brings back the Brigadier better than ever with the 92X Performance!

Smith and Wesson just announced the latest addition to their product lineup: the 380 Shield EZ Pistol. Handguns

S&W Introduces Performance Center 380 Shield EZ Pistol

Jim Grant - April 23, 2019

Smith and Wesson just announced the latest addition to their product lineup: the 380 Shield EZ...

Colt announces the release of the much-anticipated Colt King Cobra Target revolver. Handguns

Colt Announces King Cobra Target Revolver

Colt's Manufacturing Company LLC - August 21, 2019

Colt announces the release of the much-anticipated Colt King Cobra Target revolver.

See More Handguns

GET THE MAGAZINE Subscribe & Save

Temporary Price Reduction.

SUBSCRIBE NOW

Give a Gift   |   Subscriber Services

PREVIEW OUR CURRENT ISSUE

GET THE NEWSLETTER Join the List and Never Miss a Thing.

×