Customizing the Browning Buckmark Pistol for Competition

The Buckmark series of pistols have been offered by Browning in various styles for a good number of years. The Nomad, Med alist, and Challenger series of pistols predate the Buckmark, and except for minor differences, are mechanically similar. While the Buckmarks are relatively inexpensive, some models fall into the moderately expensive category when compared with other rimfire semi-automatics that demonstrate the same type of performance.

When choosing a pistol for modification, however, the least expensive models in the Buckmark line are every bit as good as the more expensive ones. If you’re going to replace the barrel, it makes sense to find one with a standard barrel, as there’s no need to pay for something you’re not going to use. Aftermarket barrels are available for this pistol, if you have reason to replace the factory barrel. I ordered and installed a Volquartsen compensated barrel from Brownells for the gun used in this article.

This barrel changes the balance of the pistol, since it is not only heavier, but longer than the factory barrel. In my opinion, this improves the balance and feel for a one-handed sport such as Bullseye. For somebody just starting out in target competition, Bullseye or otherwise, it’s a good idea to begin with an inexpensive pistol. If you stick with the sport, you can select a higher-quality target pistol later, after learning the basics and deciding what you like and dislike.

In my view, if the gun is capable of groups tighter than the shooter’s ability to hold, then it’s a good one with which to start. There are a number of different manufacturers to choose from, and although many people prefer Rugers for a number of reasons, I like the feel and balance of the Buckmark. For anybody shooting below the Master level, I don’t think any minor difference in mechanical accuracy would be noticeable between these pistols.

One of the big advantages of the Browning versus the Ruger is the restricted-parts issue. You can order barrels, hammers, sears, and just about any other part directly from the factory. Nevertheless, if you are modifying this firearm for a customer, remember to advise him in writing that the work involved will void any warranty from the manufacturer. A good reference for detail stripping the Buckmark pistol is The Gun Digest Book of Firearms Assembly/ Disassembly, Part 1: Automatic Pistols, by J. B.

Wood of DBI Books. It can be purchased from the AGA at a significant discount. There can be some truly aggravating moments The one shown here has a charging handle installed at the rear of the slide. while working on this pistol, but a copy of this book will make it a snap. The following are critical areas that will need some work to improve the function and consistency of the Buckmark, thus enhancing its overall mechanical accuracy. After these are covered, I’ll go into some practical accuracy issues.

Grips Normally, grips wouldn’t enter into a discussion on mechanical accuracy. On these pistols, however, the grips serve like sideplates on a revolver, and unless proper attention is paid to their function, the mechanics can suffer. If the gun owner prefers to keep the factory grips, take a look at the inside surface of both grips. If the pistol has seen much use, you may notice some wear on the top inch or so.

The trigger bar, its spring, and the magazine-catch spring are held in place by the right grip; while the slide stop, return spring, thumb safety, and safety detent plate are held in place by the left grip.

Most of these rubber grips have metal backing plates on the underside. Check for this, and if there are metal plates present, I suggest you remove the paint to expose the metal on the underside of the grips. This coating should be very thin. Polish the top half-inch or so of the metal on the right grip to reduce friction on the trigger bar. On the left grip, put a good polish on the area surrounding the slide stop.

I would also recommend doing the same along the middle of the plate, as the magazine thumb button may come into contact with this area. If the paint is worn through here, indicating friction between the magazine thumb button and the steel backing plate on the grip, use a file to remove just enough metal from the thumb button to provide adequate clearance. If you’re using aftermarket target grips, it’s a simple matter to attach backing plates to the underside.

There are grips out there that leave the wood exposed on the underside. Don’t skimp on this, because even if you smooth the wooden surface to a mirror polish, oil, solvent, and debris will quickly migrate into the area and cause havoc. To make a quick pattern for the backing plates, trace around the existing grips on a manila folder, then come in 3/16 inch from all outside edges. Take care to make enough clearance for the thumb safety and slide stop on the left grip.

For material, 1/16-inch-thick mild steel would be a good choice. I wouldn’t recommend aluminum because of galling concerns. Once the patterns are made to your satisfaction, using a suitable marker, trace around each pattern on the steel stock. You’ll have to drill a few small holes in the plates to clear both the trigger-bar pin on the right side, and the roll pin that protrudes on either side from the lower front portion of the grip frame.

The roll pin serves double duty for retaining the magazine ejector and spring, and also as a means of properly locating the grips on the frame. And, of course, drill the holes for the grip screws. Once you have the backing plates finished, use them as patterns on the inner sides of your grips. Now you need to relieve enough wood from the grips to inlay the backing plates so the undersides of the grips are level and form a continuous surface.

Using a rotary tool or die grinder, carefully rout around the pattern line to the right depth. You don’t have to be too precise here, since you can use bedding material or epoxy to fill in any gaps. The backing plates can be clamped and epoxied in place on the grips and allowed to cure without using screws. Once the epoxy has set up, test fit them, relieving any wood, steel or bedding material that might interfere with moving parts.

Internal Parts When polishing, removing machining marks, or taking down burrs on any internal parts, remember not to remove too much material. If the defect is too deep to fix with light polishing, obtain anew part. Most of the parts in this gun are only a few dollars each or less. If you’re building up a used pistol, chances are the mainspring plunger will have some ugly gouges that could cause lock time variations and contribute to a number of trigger-pull problems.

In order to remove the hammer and sear, you must first depress the mainspring plunger with a punch, then insert a pin or punch through the frame to keep it depressed. This is how they get gouged up. They seem to be softer than one would expect. If it’s not too bad, you can clean up the mainspring plunger with files and polish all surfaces. If it’s too far gone, toss it into the bin of misfit parts and order anew one.

If you do order anew one, make sure to clean up any machining marks and polish the entire part to a mirror finish. Not only will this help the part function flawlessly, but remember that this is a steel part, riding under considerable mainspring pressure in an aluminum frame. Burrs or gouges could result in galling of the aluminum. Once you have a gouge-free and highly polished mainspring plunger, I recommend that you case-harden this part.

I can’t go into the process here, but you can order Kasenit case-hardening compound from Brownells. It’s easy to use and comes with instructions. Don’t harden the entire part by heating and quenching, as it may become too brittle and break at an inopportune time. Take a look at the hammer link. Make sure there are no surface imperfections at the bottom where it rides in the cup of the mainspring plunger. I recommend that you smooth up and polish this area also.

Inspect the hammer-pin bosses on the hammer, and remove any slight imperfections. The same goes for the trigger bar, and the slot in the right side of the frame in which it rides. Put a good-quality polish on the trigger bar, but be careful not to change any of the edges where it interacts with the sear. Break, but don’t round off, any sharp edges on the remainder of the trigger bar. In the Buckmark’s trigger-bar slot, remove any paint in the slot and make

Once installed, grind the screw flush with the inside surface. Mounting the charging-handle screw in this area does not affect any critical bearing surface. sure the area is smooth and level. As with any firearm, it’s a good idea to inspect all pins relating to the hammer, sear, and trigger. Ensure that the pins are straight and free of burrs. If you find a problem, it’s probably not worth your time to try and fix the pin. Chuck it into the bin of misfit parts and order anew one.

Make sure to carefully polish and fit all pins. Take it easy on the polishing, though; you obviously don’t want to reduce the diameter of the pin to the point that it’s a sloppy fit. Just a few shoeshine strokes with crocus cloth or strips of cloth-backed 300-grit sandpaper should do the trick. Sight Base The sight base serves an important function on this pistol, providing a means to hold the slide and recoil-spring guide in place.

If you have a standard pistol, you can purchase an aftermarket sight base designed for Weaver rail scope mounting from a number of suppliers. This is actually a good thing, as you can hang onto the original sight base, and switch between optics and iron sights at will. Some of these pistols are factory supplied with a means to mount a scope or red-dot sight. It’s possible to remove some of the vertical play between the slide and the frame with a touch of judicious filing on one of these aftermarket sight bases.

Removal of a little material where the sight base mounts both forward and rear results in lowering the sight base, which in turn lowers the slide against the frame and removes slack. I’ve tried it with no vertical slide play whatever, and while the pistol seemed a bit more deliberate and precise in operation, there was no measurable increase in accuracy. I had to make adjustments to the magazine lips in order to lower the angle of the rounds so they wouldn’t hang up on the slide as it cycled.

One thing that’s important to note here is, when the vertical slack is taken out of the slide in this manner, you have to keep an eye on the breechface and make sure you’re not lowering it to the point that it’s misaligned with the chamber. This will obviously cause feeding problems and misfires. Since there was no observed increase in accuracy, and increased potential for malfunctions, I can’t say I recommend the procedure.

I’m including my experience with it in this article as a warning, in case you or the customer are tempted to try it. The above problems could be resolved by lowering the barrel in the frame, but in order to do that properly, you’d have to remove material from the frame. You might also have to weld up and recut the barrel-retaining screw hole in the barrel lug. You could make it work, but the work involved would cost two to three times what the pistol is worth.

Practical Accuracy Improvements This pistol’s trigger suffers from a good bit of over-travel, and Browning has wisely installed trigger stops on a number of Buckmark models. If the pistol you’re working on doesn’t have one, a small diameter set-screw installed for that purpose in the center of the trigger is a must. These triggers are composed of a soft material, so use care when clamping the trigger for drilling. It’s very easy to leave visejaw imprints on the plated surface.

As with all set-screw trigger stops, use Loctite when assembling to keep the screw from backing out. Grip improvement is always a good idea on a target pistol, not just the grips themselves, but on the back and front straps of the frame. I personally don’t care for checkering or stippling aluminum, and I’ve tried the adhesive-backed grip tape. I like the feel of the grit, but don’t care for that solution either, as oils and solvents usually start it peeling up pretty quickly.

One technique you can use works just as well if not better than stippling. It can be used on any firearm, on wood or metal, and is unaffected by solvents or oils. I use it on all of my target firearms. You’ll need a good firearms-grade epoxy that is designed to withstand solvents, some

silicon-carbide abrasive grit, epoxy dye, and an acid brush. All of the above are obtainable from Brownells. I use Acraglass and 600-grit dry silicon carbide. Mix it up properly, apply it with an acid brush, and you’ve got a great looking, non-peeling grip surface. If you ever need to remove it, it comes off easily with a wire wheel. The great thing about this method is you can create sharp edges, angles, and patterns using masking tape.

I’ve found that the best grip surface is produced by mixing in 1.25 parts of silicon carbide for every one part of epoxy. I mix in just enough black dye to make the mixture opaque. Apply the mixture with an acid brush, using a dabbing motion. This enhances the coarseness of the surface after it dries. While the epoxy is still wet, but has gotten tacky enough to stay put, I carefully peel the masking tape up, and then let it cure overnight.

Charging Handle One of the most common gripes with the Buckmark is the difficulty encountered when working the slide. Not only is it hard to overcome Figure 1. mainspring pressure, the design is just not ergonomic. This can be painful, as the slide edges bite into the thumb and index finger, and feels even worse if it slips out of your grip. If you have ared-dot sight installed, the problem is aggravated.

The newer models have small protuberances on the rear of the slide to compensate, but even this change is inadequate. Motivated by the ease of charging the AR-15, I designed a charging handle that is similar in function. In use, the shooter grips the pistol with one hand, with the muzzle pointed downrange, and uses the other hand to work the slide, with the index and middle fingers used to pull at the same time on either side of the charging handle.

This small addition has made this pistol the most convenient and easy-to-work firearm I have ever used on the line. This part can be easily made from aluminum or a hard composite plastic (see Figure 1), keeping in mind you’re trying to keep the weight down. Required tools are only a hacksaw, files, drill-press with a 1-inch sanding drum, and a buffing wheel. I think it would take longer to make it with a milling machine due to the setup time. If you have a spindle sander, it would be helpful on the concave areas.

I used a small diameter Allen-head screw to mount the handle on the rear of the slide. The slide is thick enough above the frame rail recess to get good thread engagement when drilled and tapped. The exact size and thread pitch of the screw isn’t important, but keep the diameter as small as you can to keep from weakening the slide and charging handle, while providing enough thread surface to get good engagement. Grind the screw flush on the inside of the slide.

The slide doesn’t come into contact with the frame in this area, so just get the burrs off and make sure nothing is binding. I used Acraglass between the charging handle, slide, and on the screw threads. I did this for two reasons: I didn’t want the thing flying off during a match, and my file work wasn’t quite accurate enough to provide an exact mating surface between the rear of the slide and the inside surface of the handle.

Keep in mind that it’s easy to separate epoxied parts with the careful application of a propane torch. The modifications in this article, whether done in whole or part, can produce excellent results at the range or for small-game hunting. Not only will accuracy be improved, better function and increased reliability will result as well. ■