1911/2011 Barrel Fitting Process - General Steps

[CHA-LEE]

Over the years I have fitted both Bushing and Bull Style barrels in mostly 2011 guns and some 1911's. Most of them being Para/Clark style barrels. Listed below are the General Steps I take during the Barrel fitting process. I also want to mention that I do all of this using hand tools so the average DIY person can knock it out without needing a mill or lathe. I predominately use a Brownells Slide/Frame Rail File for most of the filing needed. Beyond that its Dremel work using various Stone, Flapper Sanding wheel, and Polishing bits. Your Dremel Kung-Fu skills need to be strong if you don't want to wreck parts fast. From start to finish I can usually complete a barrel fit in about 4 - 5 hours depending on how good or bad the parts are cooperating.

 

General Barrel Fitting Steps

 

1 - Fit barrel bushing to slide -(Usually only for Bushing Barrel setup) I prefer to take material off of the Bushing during the fit as its the "Cheapest" part to screw up. The bushing should fit snugly to the inner diameter of the slide but also allow the locking lug to engage the notch within the slide without additional resistance. A sturdy Barrel Bushing Wrench makes this fitting process a lot easier when the bushing is really tight fitting to start off with.

 

2 - Barrel hood width to breach face width fit - Using a Barrel Alignment Block to keep the barrel centered in the slide, remove material from both sides of the barrel hood until the barrel hood width is just narrower than the width of the notch in the breach face. One side of the barrel hood usually needs more material taken off vs the other so don't assume that you can simply take and equal quantity of material off both sides to match the measured width of the breach face. For me, this process is at least a 15 - 20 time In & Out iterative process as I am slowly taking material off the appropriate side of the barrel hood to get it closer and closer to the correct fit. If its a Bushing barrel setup, you want the bushing installed during the barrel alignment block fit check.

 

3 - Barrel hood Length to Slide fit - With the barrel installed as far as it will go against the breach face I push the barrel upwards as far as it will go then mark the top of the barrel chamber where it meets the first upper lug in the slide. This will give me a general understanding of how much material I need to take off the back of the barrel hood. I usually grind off the bulk of the barrel hood material with a dremel & stone bit, then finish it off with a file while paying close attention to the angle of the cut (vertical & horizontal) on the end of the barrel hood. Once again this is at least a 15 - 20 time In & Out iterative process as I am taking material off to get the fit closer and closer. When this cut is performed properly the full width and height of the back of the barrel hood should be in contact with the breach face when the parts mate. Achieving the "Full width and height Contact" between the barrel hood and breach face is not an easy task to achieve using hand tools and free hand filing. When the appropriate length of hood is removed from the barrel the upper locking lugs on the barrel and slide should engage without resistance. You should also not be able to shift the barrel front to back within the slide when the upper lugs are engaged.

 

4 - Barrel & Slide Upper Lug Depth measurement - When fit properly there should be 45 - 50 Thousandths of an inch of barrel upper lug lock up height vs minimum lug unlocked height. Start this measurement by placing the barrel in the minimum lug unlock height condition by dropping the barrel down and pulling it forward slightly so the barrel and slide lugs are touching tip on tip. Measure from the top of the slide to the top of the chamber. Write down this measurement. Move the barrel back into the fully back and upward locked up position. Measure from the top of the slide to top of the chamber in the exact same location on the top of the slide. Write down this measurement. Subtract the first measurement from the second and that will give you the current upper lug lock up height. The "Locked Up" position measurement will need to be redone several times during the upper lug and barrel tip fitting process as you remove material from those parts.

 

5 - Barrel Upper Lug & Barrel Tip fitting process - Increasing the height of the barrel lockup depth requires removing material from either the recesses of the barrel lugs, outer edges of the lug tips or from the outer circumference of the barrel tip (top or bottom). Knowing where the material needs to be removed from requires evidence of mechanical interference. You can use a layout fluid like Dykem or something simple like a Sharpie Marker. I prefer to use a Green Sharpie marker as its not a messy as using Dykem. Either way, use a marking ink of some kind to fully cover the upper lugs and the outer surface on the tip of the barrel. Let the ink dry then insert the barrel in the slide placing it in the fully locked up position. If its a bushing barrel setup, make sure the bushing is installed as it normally would be when the guide rod is installed. Install the Barrel Alignment Block to keep the barrel aligned within the slide. While holding the slide upside down (lower lugs pointing upwards) use a plastic tipped hammer strike the barrel in the lower lugs area several times with a minimal amount of force. This hammering shouldn't damage any parts. The hammering function is performed to expose the mechanical interference "High Spot" which are keeping the barrel from locking up to the 45 - 50 Thousandths depth. Remove the Barrel from the slide and inspect the barrel lugs and tip of the barrel for ink removal. Where the ink has worn off is where material needs to be removed. Remove a minimum amount of material from the "High Spots" then reapply the ink and repeat the barrel install, align, then hammer process. Repeat this process as many times as needed to achieve 45 - 50 Thousandths of upper lug lock up depth.  For me, this process is at least a 15 - 20 time In & Out iterative process as I am slowly taking material off the appropriate "High Spots" to get it closer and closer to the correct fit.

 

An optional method to determine if the correct Lock Up Height has been achieved is to use a Barrel Alignment Gauge which is inserted into the end of the barrel and the tip of the gauge aligns with the firing pin hole in the breach face. I am yet to NOT have this Barrel Alignment Gauge successfully pass into the firing pin hole if I am using a 45 - 50 Thousandths lock up depth as well as the Barrel Alignment Block while performing the depth fitting.

 

6 - Barrel Lower Lug Fitting Prep - At this point the Barrel to Slide fit should be complete. Now we need to secure and lock the Barrel within the slide so the lower Lugs can be cut properly. Install the barrel into the slide. Install the Barrel Alignment Gauge on the opposite end of the barrel so that the guide rod area is clear. Install the Barrel Holder into the guide rod tunnel of the slide then tighten down the set screw to secure the barrel in a fully locked up and straight position.

 

7 - Cutting the Barrel Lower Lugs - Phase 1 - Install upper onto the Frame and push it back onto the rails beyond the start of the lower lugs vs the slide lock pin hole position. Using a Barrel Lug Fitting Kit with the smaller 0.186" cutter, cut the lower lugs until the cutter fully engages the back of the lower lug angle on the barrel. You will likely need to cut a little, retreat, clean the cutter of chips, lube and cut some more several times before you reach the back angle of the lugs. Repeat this process with the larger 0.195" cutter. When finalizing the lower lug cut depth from a front to back perspective, its important to ensure that the disconnector will be in the "Full Up" position when the barrel is fully locked up in the "Closed" position. This means that you may have to sacrifice the front or back slide to frame alignment when the front to back depth of the lower barrel lugs has been set correctly. Setting up the correct disconnector notch in the slide to disconnector tip depth position during this process will ensure that the timing of the gun will be retained. In a new gun build the frame to slide front and back alignment is performed AFTER the barrel fit by taking material off of the frame or slide as needed align them. This is how important the lower barrel lug front to back cut depth is to the Timing of the barrel locking and unlocking as well as disconnecting.

 

8 - Cutting the Barrel Lugs - Phase 2 - After performing the lower lug cutter process additional filing or stoning of of the lower lugs is usually required. Remove the Upper from the Frame. Keep the Barrel secured in the slide with the barrel holder. Using Dykem or a Sharpy Marker, ink the full mating surface of the lower barrel lugs. Install the Upper onto the Frame and bias it rearward past the lower lug to frame slide pin hole. Using Gauge Pins of varied sizes (0.197 - 0.200) install the smallest gauge pin into the frame then push the slide forward until its in the full forward position. Pull the slide back, remove the gauge pin, then remove the slide from the frame. Inspect the wear patterns within the ink on the lower barrel lugs. Remove material from the lower barrel lugs as needed to even out the "High Spots". Repeat this process with increasingly larger size gauge pins until the size matches the diameter of the Slide Lock pin used for the gun. When the lower lugs are set to the proper depth there should be an even wear pattern across the full surface of the lower lugs and the slide should move into the full forward locked up position without significant resistance. For me, this process is at least a 15 - 20 time In & Out iterative process as I am slowly taking material off the appropriate "High Spots" to get it closer and closer to the correct fit. Once the lower lugs are fitted to the correct depth remove the Barrel Holder so the barrel can be removed from the slide.

 

9 - Barrel Link Sizing & eliminating Rotational interference - Make a barrel link slave pin which is just smaller than needed to retain the pin within the barrel. This is needed to quickly install and remove different size barrel links or remove the barrel link easily while taking material off of the leading edge of the lower lugs to eliminate rotational interference. Barrel links come in a wide range of lengths from #1 - #5 and even half numbers in between (such as a #3.5). The Barrel Link length needed for a barrel fit can't be determined until the barrel is fit to the slide and frame. Start with a middle length Barrel like such as a #3 or #4 and install it in the barrel using the easily removable slave pin. Look at the lowest portion of Large link hole in comparison to the top surface of the Lower Barrel lugs. The bottom radius of the large link hole should be below the top surface of the lower barrel lugs through the main front to back movement path of the link. If the bottom radius is above the top surface of the barrel lugs then the barrel will lock up on the Link instead of the lower lugs. If the bottom radius is too far below the top surface of the barrel lugs then the slide lock pin will bind against the top radius of the barrel link and the top surface of the barrel lugs. Test fit the slide lock pin to verify if there is interference or not. Test different length barrel links until the shortest one achieves the above goals. Once the correct barrel link length is determined (usually a #3 - #4 when I have done it), you can now reshape the leading edge of the barrel lugs so the slide lock pin doesn't bind when the link rotates to the forward/down position.

 

10 - Barrel Bedding Depth fit within the Frame - With the Slide removed from the frame Place the Barrel inside the frame in what would be the fully Down and Back position. The flat surface on the under side of the barrel feed ramp should bottom out on the center portion of the frame before the inner portion of the frame rails touch the sides of the Chamber. Using Dykem or a Sharpy Marker, ink the flat surface on the under side of the barrel feed ramp and the sides of the camber. Assemble the Slide, Barrel & Guide Rod then install it on the frame. Hand rack the slide 10 - 15 times. Disassemble the gun and determine if the flat surface on the under side of the barrel feed ramp is the primary mechanical interference point. If not remove material from the inner frame rails or the chamber areas until the flat surface is the primary interference point.

 

11 - Barrel Feed Ramp Depth Fit - With the Slide removed from the frame Place the Barrel inside the frame in what would be the fully Down and Back position. Determine if the bottom portion of the feed ramp is sticking back past the end of the frame. If it is, the bottom portion of the feed ramp needs to be cut forward until its flush with the frame while in the full Down and Back position. This will keep the barrel feed ramp from beating up the magazine tube or smashing into the tip of the "Next" bullet within the magazine when the slide cycles while shooting. When the proper OAL ammo is used this very bottom quarter of the barrel feed ramp is never needed during the feeding process.

 

12 - Camber Reaming for Cartridge - Using a Chamber Reamer of the correct cartridge, ream the chamber to the appropriate depth. The Chamber depth should be set so the back end of a fully loaded round will be just below the rear barrel hood. I prefer to set the chamber depth so the back end of the fully round is definitively below the rear barrel hood. Brass can vary in OAL, especially when you are reloading ammo from unknown brass sources. A "Long" OAL case can cause a failure to fully go into battery jam if the chamber depth is reamed to the minimum depth. For the Action Shooting sports we should error on the side of reliability even if that means sacrificing some potential accuracy. That being said, I am yet to see a slightly deeper than normal reamed chamber cause any level of accuracy degradation in my testing.

 

13 - Feed Ramp & Chamber Entrance Optimization - The barrel feed ramp and chamber entrance will likely have many sharp 90 degree edges or burrs. I prefer to slightly round and polish all of the sharp 90 degree edges surrounding and leading up to the chamber. The Feed Ramp transition into the chamber should also be slightly rounded and polished. Any barrel feed ramp shortening that occurred before should be cleaned up and smoothed out so there are no abrupt angles or transitions into the normal feed ramp angle.

 

14 - Ink, Lube, Assemble & Test - I will Dykem or Sharpy marker the barrel in all of the primary mechanical interference points. Let it fully dry then lube and assemble the gun. I then hand cycle the slide on an empty chamber aggressively at least 50 times then take it apart and assess the wear patterns the ink is exposing. If the wear patterns look normal, then I will redo the ink, let it fully dry, then lube and assemble the gun. Next I will use dummy ammo at the correct OAL for the pistol to hand cycle through the gun. Locking the slide back, then releasing the slide lock to chamber the rounds. The dummy ammo should feed smoothly and the slide should go forward into full battery every time. I will repeat this at least 50 times then take it apart to assess the wear patterns the ink is exposing. If the wear patterns look normal, then I will redo the ink, let it fully dry, then lube and assemble the gun. Finally, I will live fire test the gun to verify accuracy, sight it in, and fully function test it several hundred rounds. After the Live Fire session I will recheck the wear patterns the ink is exposing. Some fine tuning in any of the fitting processes may be needed during these three stages of testing.

 

Conclusion - As I stated at the start of this post, this is the "General Steps" associated with fitting a 1911/2011 barrel. I wanted to provide these General Steps to help people understand what the process is and more so to point out that its absolutely doable if you are willing to put in the effort and pay attention to the details. Fitting a barrel isn't rocket science, but its also not monkey proof like snapping together Legos. There is absolutely a "Craftsmanship" component to the process. If a knuckle head like me can figure it out, so can you. Happy Wrenching my Friends!!!

 

 

[shred]

Thanks for the writeup.. I see a lot of people that either think 'if it fits, it ships' for 1911 parts or it's a mysterious black art than only gunsmiths with a year-plus wait can be trusted to do.

 

[jwhittin]

Hi Charlie,

 

Thanks for the writeup.  I would like to get your thoughts on proper slide ID and barrel OD dimensions for matching up a slide and bull barrel before even starting a project.  Seems to me the differences between the slide ID and the barrel OD are critical to obtain a high level of accuracy (at or below 1.5" at 25 yards). 

 

Just as a reference, the 1911 spec dimensions for a bushing type barrel is OD=0.580" and the bushing ID = 0.581+0.002 which is a max of 0.003" difference.  I've checked some full custom bull barrel guns and they run as little as 0.001" difference in diameters.  Checking a couple custom guns with an unassembled slide and barrel lightly held in lockup, there is no discernable horizontal of vertical movement at the muzzle.  

 

Slide ID dimensions seem to vary a lot anywhere from 0.699" up to 0.703" or even 0.705" in some cases. What I've seen is that the factor barrels and even the semi-custom barrel manufactures only offer the bull barrels with OD=0.696 (or smaller).  That means a minimum diameter difference of 0.003" up to 0.007". Can you even attain an accuracy of 1.5" or less at 25 yards with a 0.003" barrel/slide diameter difference?

 

So if your slide ID is 0.699 or larger, seems like the only option is go with a full custom barrel shop like Bartso. They said they can make the barrel OD per your spec. Are there any other full custom barrel makers?

 

Appreciate your feedback.

Joel

[shred]

You can always turn down a bull barrel and thread on a sleeve if you want to make it tighter.  The main lockup area at the front of the slide for a bull-barrel is due to the 1-degree barrel tilt, which acts sort of like a small V-block if it's set up right.  Bob at Brazos had a series on it in Front Sight / USPSA mag not too long ago.

 

https://www.brazoscustom.com/post/installing-fitting-a-compensated-barrel

 

https://uspsa.org/magazine/display//2019-03 

 

"Typical measurements would be an outside diameter for the barrel of 0.695 inch and an inside bore diameter for the slide of 0.700 inch. On the surface, this sounds like a sloppy fit. What happens when you fit the barrel to the slide is that the barrel cams (rotates) up in the slide to lock up."

[jwhittin]

Yes, I forgot about sleeves.
 

I have those exact measurements for a LO build.  Simplifying the geometry, the barrel-slide contact area at the muzzle is basically the pivot point so the vertical elongation would only need to be half the difference in diameters (0.0025 in this case) to make contact. That seems reasonable. 
 

[CHA-LEE]

Shred beat me to it. You can't assume that the ID of the slide and OD of the barrel are engaging on a straight plane. Once the barrel starts to point down during lockup the OD of the barrel "Grows" quickly in a top to bottom Oval fashion in relation to the ID of the slide.

 

I have only seen one bull barrel swap scenario where the ID of the slide was still too big after the lock up depth in the upper lugs was complete. In that scenario, the prior barrel fit was done by increasing the ID of the slide instead of reducing the OD of the barrel. That was fixed by Tig welding material onto the top and bottom of the barrel then reshaped to increase the OD of the barrel. But whoever fit the original barrel and hogged out the ID of the slide to fit the barrel needs to be punched in the face for being an idiot.

 

All of the other Bull Barrel swaps I have done required material to be taken off of the OD of the barrel to get the upper lug lock up depth set properly.

 

I have also seen plenty of Bull Barrel fits by monkeys where the OD of the barrel wasn't considered and the upper lug depth was set to the interference between the OD of the barrel and ID Of the slide. This usually results in a very shallow upper lug lockup depth and corresponding short barrel Link like a #1 or #2. I haven't seen a boat load of guns, but the ones I have seen which had a #1 or #2 link in it didn't have enough upper lug lockup depth and something else fit really poorly. Amazingly, these guns ran and were fairly accurate, but I wouldn't expect them to last more than 20K rounds before something goes sideways in a bad way.

 

1911/2011 pistols can be built horribly and they will actually "Work". The main difference between a properly built gun and a poorly built gun is how long will it "Work" before it fails. If you want a gun that lasts 100K then it MUST be built properly.