Kart Barrels

The object of a number of projects, the 1911 lends itself well to producing accurate and reliable handguns with proper attention to detail. Over the years I have enjoyed generally good results with a variety of 1911 barrels, including those from Bar-Sto, Nowlin, and the inexpensive Roto. The only barrel I’ve encountered that was actually worn out was in an old GI .45. The rest either met with corrosion or the owner simply wished to upgrade accuracy.

Until recently, my experience with Kart barrels had been limited but I installed one in a project gun with good results. I used a Kart EZ Fit barrel and I was interested in how much time would be saved compared to complete custom fitting and what the results would be. Kart’s instructions indicated it is possible to fit the barrel in about sixty minutes. I admit that claim made me skeptical. Perhaps someone fitting a custom barrel at the Kimber or Springfield custom shop working with the same gun every day, maybe.

It made for an interesting test. The first thing was setting the barrel in the slide to check for fit. As expected, it needed fitting. The barrel bushing was sized using emery cloth with a "shoe shine" motion. This alone took a solid hour. However, the EZ Fit barrel saved time in having lower lugs that are precut and with a link pin already installed. This made fitting the hood to the slide the next step. I didn’t need to do anything to the width of the hood other than shortening it ever so slightly.

The barrel hood and slide need to be mated up for proper fit and lockup. As I chose to use a National Match bushing that was waiting for a project, this took a bit longer. If the sides of the hood are too wide, the barrel’s motion will force it onto the lower lug. If the hood is jammed tight, the locking lug does not rise correctly. They may jam against the slide stop pin. Improperly fit lower lugs may cause the barrel to tilt to one side or the other at the hood.

To verify lug contact, use heavy marking fluid, a Sharpie, sight black, or smoke the parts to indicate which parts on the barrel are rubbing or engaging more than the other and what needs to be filed to raise the barrel. Observe the hood carefully as it goes into battery. If the contact pads are uneven, the barrel hood will show a tilt to one side or the other. This occurs as the barrel attempts to go into battery. I also mark the lower lugs to verify contact with the slide stop as the barrel goes into battery.

This contact may cause the barrel to hit the slide stop, preventing it from going into battery and leaving a mark on the lower lugs. The pads are carefully filed down a little at a time and the barrel checked for tilt. As this is done, the slide stop contacts the lower lugs just slightly. Eventually, we have the three contact point lock up that is desirable for accuracy. The barrel is held tightly by the raised portions or pads on the top of the barrel and the locking lugs on the lower part of the barrel.

The lower lugs press against the slide stop and the barrel hood also exerts pressure. It may also be necessary to shorten the barrel hood as the fit became tighter. Anyone not completely familiar with the function of the 1911 should not fit a precision barrel—or, I should say, attempt to fit a precision barrel. This isn’t the first gunsmithing project to be undertaken.

Kart’s approach of securing a good lockup is different, however, as long as the locking lugs and the barrel bushing are tight and fitted well, the pistol should be accurate. All points must be accurate. Tight and well-fitted locking lugs are good but the barrel bushing must also be snug. By the

This is the newest version of the Kart. same token, the barrel bushing may help if properly fitted but the barrel must also be match grade for proper results. The lock up points must be understood. There are four lockup points on the barrel: Locking lugs, barrel bushing, sides of the hood, and the bottom lugs. Let’s begin with a quality, match-grade barrel—in other words, oversized. The barrel hood is larger than the breechface opening and must be fitted.

When filing, be certain of having 0.003" clearance on each side and that the hood remains parallel to the breechface sidewalls. Straightforward, but this still requires some attention to detail. The barrel extension is also longer than on drop-in barrels and must be measured with a hood gauge and properly shortened. Carefully cut the barrel on a lathe until the hood is about 0.003 longer than the hood-gauge measurement. At this point, the handwork comes in.

Carefully file the barrel until the unit slides into the lugs with no excess movement for a good, tight fit. The rear cut controls upward motion and must be carefully inspected during fitting. Place the upper lugs in the slide slots, then carefully and slowly tap the bottom lugs with a brass hammer. Tap toward the muzzle for proper fit, allowing the barrel to move more fully into contact in the locking recess. Mark or smoke the barrel and file where it’s rubbed off.

Be certain your strokes are perfect, with metal filed away and moved evenly. You wish to reach a point where the barrel rests in its locking lugs without springing away from the locked position when pressed into place. In short, the barrel must be properly fitted and also perfectly centered in the slide. I find binding on the slide stop less common with modern barrels, but it can happen.

This is especially true of extended slide stops for some reason; I suppose they area bit larger overall to support the added weight of the gas-pedal-type slide lock. The hood must be centered and the bottom lug must not bind on the slide stop, but must ride smoothly against it and square properly. There has been some confusion concerning the proper length of the link.

Once the barrel lower lugs are properly filed and smoothed with a proper fit to the slide stop, measure the length from the link-pivot hole to the area that has been polished. Next, measure the area between the two holes of the swinging link. These measurements must be the same. If not, the link will not fit properly.

When using a larger diameter slide stop, this measurement becomes critical, however, I have had to use oversized slide stops on occasion (usually one from Chip McCormick) with off-specification 1911 pistols in order to ensure proper function and to snug up certain caliber conversion units. It’s important to understand the relationship between link length and barrel/locking lug to slide-stop measurements to do this. When the upper assembly is placed on the pistol and checked for smoothness and

45 gives excellent accuracy with the Kart barrel. function, any drag will normally be from the lower lug against the slide stop. This is addressed by filing and smoothing. As for the barrel bushing, normally a fitted bushing comes with the barrel. When using a tight National Match bushing, fit the bushing to the barrel. An improvement in accuracy is always realized when fitting a tight bushing. The bushing is oversize in inner dimensions and the barrel is turned to achieve a good fit.

A fitted bushing works best with pistols that are already pretty accurate but won’t make up for a sloppy pistol. The Kart responded well to a tight National Match bushing. The Kart’s accuracy is excellent and this pistol gave good results. When surplus military pistols were more common, the reason for replacement of the barrel was corrosion and wear and tear. Today, the main reason for barrel replacement is increased accuracy potential. The Kart barrel is a different type to fit.

Perhaps "easy fit" is over stressed. To do the fitting right and to achieve good results the barrel must be fitted properly and carefully. As an example, I examined a .38 Super Kart barrel that had not been fitted correctly. Misunderstanding the process and perhaps due to haste, the owner had simply filed the bumps away until they were flush with the body of the barrel rather than taking time to fit the barrel and removing only what was needed.

The results were not a great improvement over the original commercial barrel he had replaced. The amount of improvement in fitting the barrel for accuracy is often in direct proportion to the time spent fitting the barrel. Accuracy is a qualitative expression that attempts to describe the measured degree of precision an instrument exhibits. When measuring the accuracy of a time piece, for example, it’s possible to ascribe a true value since that value is known.

The true value of an accurate handgun will probably never be measured. Nevertheless, the skilled gunsmith can always improve on any handgun—even one that is already accurate. AG