September 12, 2011

Basic How-To Advice For Beginning Shotgun Work

Few guns get used and abused more than shotguns, and some easy-to-perform fixes will overcome the most common problems.

by American Gunsmith Staff

There’s something about shotguns that brings out the worst in otherwise knowledgeable people. A vast majority of shooters don’t even know how to get and keep barrels clean and shiny. Even fewer have any idea about shotgun sights and their use. Still, solving these and other problems are intimidating to the novice, yet there is nothing to most of the jobs after overcoming the initial mystique of these jobs. The easiest are removing slight surface rust from barrels and polishing shotgun bores. Installing sights that will really help the shooter also fall into the easy job category. We will cover these here in enough depth for you to take on any of these jobs comfortably.

Removing Light Rust

Rust and blueing are merely forms of ferric oxide, one of many elements or compounds that share the same formula, name and structure but differ in appearance. Taking rust off blued exterior parts is only a means of curing the effect, but it doesn’t prevent it from reappearing.

We want rust present in the color of blueing because it is the end product of ferric oxide and tends to be stable. If any of the brown rust appears on a blued part, it has come from freshly exposed steel that hasn’t reached the blue stage. This is a greatly simplified explanation of the difference between blueing and what we refer to as rust, but it is useful in explaining why you shouldn’t use any rust-removing oil on a blued surface. It will simply thin out the blueing.

There is a good way to remove slight rust from blued surfaces if the rust hasn’t gotten too much of a head start. Rust that is only beginning to appear on a blued gun can be rub­bed away without ruining the remaining blueing, if the proper type of material is used. On guns that aren’t particularly valuable or that don’t have much blueing left to protect, we use a XXXX grade steel wool.

However, the best remedy for slight rusting comes, curiously enough, from Amway, the organization more famous for household stuff. Scrub-Buds from Amway are curly scouring pads made of a soft stainless steel that doesn’t scratch good blueing, but plays havoc with normal rust in a satisfyingly selective manner.

It is always interesting to watch people’s expressions when, after watching Scrub-Buds being rubbed vigorously over a bright, shiny blueing job, they can’t find any scratches in the blueing. We usually demonstrate the stuff on a personal gun first, allowing owners to gain some confidence in the product before it is used on their favorite firearms. We suggest you try the Scrub-Buds on your own gun in an area concealed by the grips or forearm before/ using them on someone else’s gun.

Keep the Scrub-Buds material clean with trichloroethane 1,1,1 to prevent rubbing rust from one gun into another’s surface and throw the stuff away when it gets too strung out to be easy to use. Using it wet, whether from water or solvent, causes it to dig into the surface and could ruin the blueing. We use the Buds with tri-chlor when we want to remove ferric oxide from a piece of steel during machining and other work, so we know that it can remove all of the surface treatment, except chrome or nickel plating, from any steel.

With the firearm secured in a padded vise or held in a way that allows you to control it, lightly rub the Scrub-Bud over the surface to remove the rust. If that isn’t doing the job, pressure can be increased on the stainless-steel pad. The tiny rust spots should disappear, leaving some powdery rust dust on the surface. Remove this with a cleaning solvent and apply a good oil. Don’t use WD-40 or other rust-removing oils on blued finishes.

You should not try to make the Scrub-Buds work miracles by using them on any but the most subtle of rusting. If it is more extensive, we suggest using XXXX steel wool and going for the bare, oiled look. Just tell the gun owner that his options are a complete blueing job or keeping the gun very oily to prevent the rust from advancing further.

If you recommend Scrub-Buds to any owners, be sure to pass on the caution about not using the buds wet. The results might lose you a friend. We would also point out that not just any stainless-steel wool is safe to use on blued surfaces.

Polishing Shotgun Bores

Few jobs gain a customer’s confidence as much as simply polishing the interior of his shotgun barrel, a task so easy that we often throw it in with a more complicated project.

This should also be one of the first little jobs a beginning gunsmith puts in his repertoire because it can do more to cement relationships than all the other more-involved jobs together. The amount it impresses is far out of proportion to its worth, but it is well worth the doing. The streaks of lead and other blemishes removed by polishing are less harmful than they appear and will come back again, but the image of the shiny barrel is never erased from the owner’s mind.

While impressing the owner is foremost right now, the process will be needed when you have to remove dents and other barrel interior jobs covered later in the article, so store all of the polishing tips in your memory.

What do you tell your friend while he admires that shiny bore? Mention that the smooth sur­face of the polished bore will have less friction and tend to resist the buildup of lead and plastic wad material. The accompanying reduction of friction will improve the velocity of the wad through the barrel, which shortens the lead needed for mov­ing targets. Any build­­up in the bore is self-defeating, as it increases the rate of heating the barrel and faster buildup of material on the surface.

Most of the required equipment consists of things you already have, like ordinary cleaning supplies and an extra rod or two. Polishing compound used on your car will serve here as well. That spare cleaning rod could be sacrificed for used only on barrel polishing jobs.

American Gunsmith Book of the Shotgun, Chapter 1

Courtesy, American Gunsmith Magazine

While polishing the bore of a shotgun, the author uses his off hand to steady the spinning rod, keeping it from hitting the edge of the muzzle.

Even if you don’t have these items, you can get them inexpensively enough. An all-gauge cleaning kit from Brownells is only $4.12, while a Hoppe’s 12-gauge package runs around $8.09 from most suppliers. These kits typically have a three-piece rod (one section holds the handle), a jag, a bottle of solvent/lube, and a slotted endpiece for a rag.

We keep cleaning rods and a brush on hand for almost any gauge or caliber because, as a courtesy to the owner, the bore should be cleaned on any gun you’ve worked before it is returned. If you have a good rifle cleaning kit, you can buy a shotgun adaptor, an aluminum or stainless-steel piece that adapts the 5/16-27 thread on the brush to the 8-32 thread on the rifle rod.

Cleaning brushes should cost about $1 apiece and are usually sold by gunsmith distributors in packages of three. We highly recommend soft stainless steel Cyclone brushes for removing tough leading. The Cyclone’s wire is coiled into a spiraling shape that is hard to describe but effective on almost any fouling. The Cyclone brush is the only stainless brush that we can recommend from experience, although several others are available. You must be careful to avoid introducing small scratches that defeat the purpose of polishing a bore.

You will need some clean cotton cloth to run through the bore to remove the polishing compounds and smooth out the oil coating you gave it. Nylon swabs or mops, as they are more commonly called, do an admirable job but must be washed frequently if you want the best cleaning. For that reason, we usually use the slotted tip furnished with the cleaning kits to run a rag through the bore for the final touch.

If you use the nylon mops, have several on hand so you can rinse them out and still have a dry one to use in the final pass. Get several sizes; they can be used on other jobs as well. The .410-sized mop works nicely in .45 ACP bores. In fact, for every time we use the mop on a .410, we’ll use it 100 times on a .45. Other gauge sizes are often used in cleaning out magazine tubes on guns of the same gauge.

There are many solvents on the market, but like many other shooters, we have strong ties to Hoppe’s Number 9.

Compounds found on the shelves of any automotive supply house will be used for the main barrel polishing. You don’t need large quantities because you won’t use nearly as much on guns as on cars. The majority of bores can be slicked up with Du Pont’s white polishing compound, although we use their red-brown rubbing compound on some of the stubborn bores.

For the very final touch, Happich’s Simichrome Polish has been my choice for more than 35 years. We are comfortable recommending it to anyone and for any metal. Simichrome will put as fine a mirror finish as you can imagine on steel or any other metal, including aluminum. It stretches so far that you will need only the smallest tube. Simichrome should cost about $3.75 for a 1.76-ounce tube. Brown­ells sells a product called Flitz for about $5 per 50-gram tube. One advantage Flitz has over Simi­chrome is that it is nonabrasive and can be used on blued surfaces without hurting the blueing. Simi­chrome will shine up a blued surface, but without restraint you will rub through it. More on that later.

The first step in almost any gun job is to clean the gun until you can make a clear judgment of its condition. We remove the barrel from the gun whenever practical to keep from subjecting the gun’s working parts to the abrasive compounds. It is also prudent to keep the drippings from cleaning as far away as possible from the workings of the shotgun.

This preliminary cleaning will make any lead or plastic deposits stand out against the clean surfaces of the bore to be more easily seen. A good bronze or Cyclone bore brush, along with some solvent, should remove any lead deposits visible in the bore. If they don’t, there must be some surface roughness that may or may not be smoothed with a good polishing. This can be done in the next step.

If you have an electric drill motor handy, there is no better time to pull it out than now. It will not hurt to use the bronze-bristled brush with power because the barrel is many times harder than the bristles of a good bore brush. However, always use lubrication of some type to avoid leaving brass or bronze streaks in the bore. We use the Hoppe’s solvent for this task.

Use a spare cleaning rod without a handle attached to a 1/4-inch drill motor in this job. The best kind of rod for any cleaning job is stainless steel. Aluminum or coated rods can become imbedded with gritty particles, turning them into abrasives that can destroy a muzzle. To be sure of what we are getting, we make our own cleaning rods. One length each of 13/64- and 5/32-inch type-404 stainless-steel round rod stock, along with a RIG 8-32 to 5/16-27 adapter, will make rods for all cleaning needs. (The smaller diameter rod is for .17-caliber cleaning). The 13/64-inch rod is threaded (8-32) on one end and cut off to a 30-inch length. The other end is left plain so it can be powered by an electric drill motor.

The rod is put into a lathe for threading so the threads will be coaxial with the rod and not cause the bore brush to wobble when turned by the drill. Drill the end of the rod with a #29 (0.136-inch) bit and tap the hole with an 8-32 tap, using the tailstock of the lathe to align the tap. Follow that with a #19 (0.166-inch) bit to counterbore about 1⁄16 inch deep. This will make room for the slight portion of the bore brush’s shank that has no threads.

Using the rod you just made or bought, install the right-sized bronze bore brush and dip it in solvent. Retaining as much of the solvent on the brush as possible, insert it into the barrel from the most easily accessible end and chuck up your electric drill motor onto the rod.

American Gunsmith Book of the Shotgun, Chapter 1

Courtesy, American Gunsmith Magazine

Equipment and supplies needed for shotgun bore polishing are easily obtained. The bore brushes obviously require using a cleaning rod.

Reciprocating the rod as the drill is turning, scrub the bore thoroughly, concentrating more of your time where the lead deposits are the worst. This will usually be near the muzzle end where the shot cup is squeezed by the choke. The hydrostatic effect of the shot cup being accelerated by chamber pressure and the dead-still inertia of the mass of the shot cause a great outward force against the sidewalls of the shot cup. It is common for lead shot to penetrate the cup, especially in the area of the slits in the sidewalls, leaving lead marks on the surface of the bore. It is for this reason that a different shotcup material with no slits is required for steel shot.

All the lead streaks must be removed because they could mask the surface when we are using an abrasive compound later, causing the metal to be washed away more to each side of the lead deposits. We’re talking of a very slight amount of washing away but the lead will need to be removed before the job is over, anyway.

If bronze brushes and a solvent won’t remove all of the lead, there is a greater problem with the bore than simple leading. The marks may be scratches from steel shot, which was handloaded without the proper steel-shot cups, allowing some of the steel shot to score the barrel. Small numbers of scratches can often be removed with the polishing we are to do later.

If there are only minute scratches in the barrel, we suggest using a rubbing compound of the reddish-brown nature like the body shops employ to rub out fresh paint. In severe cases, we go through a 400 grit wet-or-dry sandpaper routine before the rubbing compound. This procedure should not be used except in cases of great scratching. In most cases, it will be appropriate to skip the sandpaper and go to the rubbing compound.

If there are some real scratches in the bore, you will have to use some sandpaper strips on a rod to remove them. Splitting an appropriately long rod with a hacksaw allows you to put the end of a sandpaper strip in and use the rod like a hone. It’s easier on the budget, too.

To use the split rod and sandpaper strip honing system, make the rod with the slot in the end first or use the bronze bore brush to drive the sandpaper. Cut some 400 grit wet-or-dry sandpaper about 2 inches wide and the length of the sheet and get some light oil or kerosene handy. Put a bronze bore brush on the rod with the shotgun adaptor and drill motor. From the operator’s position, the brush will be driven in the clockwise direction so the sandpaper must be wound around the brush or the split rod in a counterclockwise direction.

Place the barrel in a padded vise and situate it so you will be able to run the cleaning rod in and out comfortably. The barrel will get hot in the area being sanded, so in addition to steadying the piece, the vise lends comfort to the operation. Fold about a quarter inch of one end of the paper, insert it between some bristles of the brush and wrap the paper around the brush. With the paper tightly in its wound condition, put the brush/sandpaper end into the shotgun’s bore and push it several inches in. Squirt, drip, or slosh some kerosene or oil into the bore, letting it run down onto the paper and through the brush. Turn on the drill and move the rod in and out while the sandpaper is turning, concentrating most of your efforts in the vicinity of and over the scratched area.

The drill motor should be run fairly slowly, not much more than half its maximum speed, and keep the sandpaper liberally flooded with the fluid. The bronze bristles will keep the right amount of outward force on the sandpaper so you can concentrate on your even, reciprocating motion. The barrel may be hot, so use caution when handling it in the area of sanding.

Inspect the bore after several minutes of sanding, replacing the paper if it’s loaded up or smooth. Since the paper is wrapped more than one turn around the brush, you will probably be able to swap ends with the same piece and get more use from it. As long as the paper is kept clean and flooded sufficiently to float sanded particles away, it will cut and not leave scratches. You will be able to tell when the sanding marks have removed all the blemishes from the bore, as your reciprocating motion and the rotary motion of the drill have combined to give a crosshatched network of woven brushmarks.

Scratches from shot are longitudinal and easily distinguished from the sandpaper’s marking. The 400-grit paper should make the crosshatched pattern so fine that it will be quite difficult to see the individual scratch marks. Subsequent polishing with rubbing compound will remove the slight crosshatching marks.

After honing has produced a good, even woven pattern in the bore, it is time to work with the rubbing compound and polishes. First, we need enough properly sized wool mops so that we can use a mop to hold the rubbing compound while smoothing the bore. If you don’t want to use yours that way, wrap a piece of cloth or good paper shop towel around either the mop or one of the bronze bristled brushes and smear it with the rubbing compound. Insert this into the barrel, either at the chamber end or the muzzle, whichever is easier for that particular firearm, and spin the polishing device while reciprocating it from end-to-end.

Continue to use this rubbing compound until the surface is bright and shiny, then change to the Simichrome polish. This should only be used after the rubbing compound has gotten the bore to being almost shiny enough to be left as is. The Simichrome will be used to bring the bore up that little bit extra to a literal mirror finish. An entire barrel takes only about a BB-sized drop of the compound. The stuff keeps working when it’s only a memory on your rag, so don’t pile it on when the rag looks black and polish-free.

American Gunsmith Book of the Shotgun, Chapter 1

Courtesy, American Gunsmith Magazine

Bead-sight installation is easy with just a few tools. A shallow-angle drill and bottoming taps are among the most commonly used. Exactly what you’ll need will vary slightly based on the type of bead you place on the shotgun.

When the bore looks like the best mirror you have ever seen, clean it with a rag on a slotted jag or with a clean mop and lightly oil it with bore solvent/lube. Clean the entire gun again, finishing the job by wiping down the exterior of the gun and rubbing it lightly with oil.

Be sure the gun is clean inside and out; a dirty barrel can make or break a good batch of work. To inspect your work, have a bore light handy to shine from the other end of the barrel, or at least hold the gun up to a fluorescent light or mirror.

Installing Bead Sights

The numbers game tells us that installing bead sights will be one of the most common shotgun jobs we handle. The more of something there is, the better chance something goes wrong.

Bead sights come in any number of sizes, shapes and materials, not to mention configurations and methods of attachment. One shotgun may have a bead sight on the muzzle and a smaller bead at mid-barrel. Older shotguns usually have solid metal beads while more modern pieces might use fluorescent plastic “glow worms.” They may be soldered in place or they might be threaded into or tapped into a tapered hole.

Several shotgun sights fit the general open sights category, yet are quite different. They range from solid round balls to double-ended translucent “worms.” Each type has a following. The ball-shaped beads are preferred for their conservative look, but a few feel strongly about the fluorescent-colored sights that were designed to pick up light and scream for attention. Some of the fluorescent sights are opaque and one-ended, with a bullet shape pointed back toward the shooter. This “bullet” typically has a central cone that is dayglow red inside clear plastic. These have threaded shanks pointing downward to be screwed into the rather large tapped holes. These are hard to miss; they’re about three times the size of the conventional bead and stick out quite prominently. We have only used ones like this with 8-40 pitch threads.

Another popular worm has two ends in line with the bore, is transparent or translucent and quite large at about 1/2 inch long. The double-ended worm gives you twice the chance to line up with the barrel and be the right height. Since shotgunning isn’t as demanding of an exact hit as a rifle, it seems as if the worms are close enough wherever they stop. We don’t like this, but we satisfy ourselves by cutting the threaded end off until the sight screws down against the barrel. There isn’t this problem with the ball-shaped beads, since they stop when the ball touches the barrel or ramp.

Brass is the most prevalent material used for shotgun sights, and for good reason. It stands out better against a blue sky than a silver color like stainless steel and doesn’t have to stay shiny. Brass is requested 10 times for every one time another material is picked.

There is no doubt that the brass ones are more tolerant of the rigors of installation, especially when the sight called for is a tapered shank type that must be installed with a hammer. We do our best to talk customers and friends out of replacing their tapered shank beads with the same type. It doesn’t make sense to use that method of retention when there will be sudden shocks and vibrations in their mounting holes. We almost always replace them with threaded beads and plenty of thread-locking compound. If they cannot be talked out of the tapered-shank bead, we use a tough, flexible adhesive on it before hammering it into the hole. As much as we like it, cyanoacrylate glue is just too brittle to last.

A bead threaded or wedged into a ramp is less likely to come off as more material beneath it means more threads or a deeper tapered hole. Additionally, muzzle gas pressure won’t be pushing up on the shank of the bead. Finding the center of a rib will also be more easily done than finding the very center or top of a plain barrel. We will get into how to determine the top of a barrel in a bit.

Most of the threaded sights for shotguns have threads of the 6-48 persuasion but you will occasionally run into an 8-40 or 3-56 shank. The 8-40 threads are so large in comparison to the bead that you rarely run into one that is stripped. Some of the 3-56 threads will be stripped, but you’ll be able to drill the hole larger and tap it for a 6-48 sight.

You will need a shallow angle drill and bottoming taps to tap to the very bottom of the hole for the sight. We never have to buy bottoming taps. We grind any tap that breaks flat on the end, which lets it tap even deeper into a blind hole than a bottoming tap. Just keep the tap cool while you are grinding the end so you don’t ruin the temper and it will make a swell bottoming tap. We also grind some old drill bits to a flat bottom so that they will cut a square-bottomed hole, using them for the last 0.030 inch only, of course.

If there is no ramp, it may be difficult for the less-experienced gunsmith to find the top of a barrel and know where to mark for the sight or ramp. If you like to live dangerously, you can eyeball it, but this method has sold quite a few shotguns to gunsmiths. There are some good, but expensive, devices on the market that help find the very top of a barrel. These do nothing you can’t do for yourself, they just make it easier.

If the receiver has flat, vertical sides, it should be easy to get the gun situated in an upright position in a vise or clamped to a workbench. All that is needed from this point is a horizontal beam to touch the barrel on the upper side and it will be the center/top of the barrel. This can be easily achieved with two squares. The upper square can be raised and lowered along the vertical edge of the other to give the upper horizontal edge. Where this touches the barrel is the spot to punch before drilling. We put the bead about 3/8 inch from the end of the barrel, but you should decide for yourself or ask the owner if he has a spot picked out.

American Gunsmith Book of the Shotgun, Chapter 1

Courtesy, American Gunsmith Magazine

The sight-bead hole on a side-by-side must be drilled with a blind bottom and tapped to bottom. The same principle applies when installing a ramped sight.

A good replacement for the double square method is to use a small bubble level on the upper surface of the barrel and mark the place it touches when the bubble is in the center. If the receiver is spaced off of the bench with a reliably-parallel spacer block, a square held on edge on the bench will touch the barrel’s upper surface on its top line.

Mark the top line with a white pencil or other method that doesn’t endanger the blueing and punch a dimple to locate the drill. Drill through barrels without a rib and tap the hole for the bead. Install the bead with sealer and let it dry. The shank that intrudes on the inside must now be removed. We do it by grinding extreme amounts away with a Dremel tool and a sanding drum and finish up with a piece of 320 grit white sandpaper on a wood dowel. The finishing sanding is done with 400-grit wet or dry paper, and then the interior is polished as described earlier.

If the barrel is ramped, the sight bead hole must be drilled with a blind bottom and tapped to its bottom. (The same procedure is used on a side-by-side shotgun.) It is wise to arrange some sort of stopping device on the drill bit or have a very steady hand if the material is thin. It would be a shame to drill into the bore of a ramped barrel. With the hole to your liking, tap with the appropriate-sized tap using a plug tap to start the threads and a bottoming tap to finish to the bottom of the hole. In the case of quite a few side-by- sides, the hole in the rib will go through into a void between the barrels. This is actually a good sign, rather than a cause for alarm, since it allows you to install the bead without finishing the inside of the barrel or cutting the shank to a certain length.

Wash the tapping fluid from the threads with a solvent such as trichloroethane 1,1,1 or acetone and blow the solvent from the hole. Use a bead installer or small drill chuck with a handle to put the bead in its place. Use some sort of sealer with it.

We have always liked shotguns that have rifle-like ramped front sights, but they are more demanding to install than the simple threaded bead. The little ramp is silversoldered on with flat ribbon silversolder and a clamp. Clean the blueing away from the areas to be mated, flux them both, clamp them in place with some ribbon silversolder between them, and slowly add heat until the solder melts. It will suddenly become a silvery line that spreads around the interface between the ramp and the barrel. Let it cool before removing the clamping pressure. If the ramp doesn’t come with a threaded hole in it, then you still have to drill and tap it for whatever sight you choose.

Tapered-shank sights should be installed into straight-drilled holes unless you happen to have a drill that is tapered just like the shank. This is unlikely, so just tap them into the straight hole like they were meant for each other. The tapered shanks will deform to give the unit some grip and are designed to stay in without a sealer. I’ve never left one dry when tapping it into the hole, trying everything from silicone calk to cyanoacrylate glue. We were using silicone calk the only time we had a tapered bead come out, so we don’t recommend it. It may have been the execution, but we haven’t wanted to test it again. The red Loc-Tite or another brand of bearing sealer will hold the tapered shank in the hole rather well. You must get the hole deep enough to accept the shank if the hole is blind, as the shanks of the plastic beads are rather flimsy. If the hole goes all the way through the top of the barrel, the bead should be tapped with a mallet until it is against the top of the barrel and the sealer allowed to dry before shaving off the portion that extends into the barrel.

Mid-Barrel Beads

Installing a small bead in the middle of the barrel has always helped my customer’s score or harvest and has gotten me lots of repeat business. That’s why mid-barrel beads are among my favorite shotgun jobs.

The job is easily sold. Demonstrate the concept with a large wooden dowel, about 3/4 inch diameter by 36 inches long. Place a single bead at the end of the dowel on one side. Do the same on the opposite side of the same end but add a bead of about half its diameter. Have the owner sight down the single bead side and notice how he must move his eye to check see if the barrel is in line with the bead and the target. Then try the side with two beads. The smaller one is closer to his eye and appears about the same size as the end bead. The two beads easily line up on the target without having to make an effort or even moving the eye off the target.

This rarely fails to impress someone who hasn’t shot with a mid-barrel bead before. If there is a shotgun with a ramp on top of the barrel handy, they can decide for themselves if two beads are easier to pick up than their ramp was. Few realize how much trouble a ramp is until they try the double bead. We have several holes threaded in the dowel so we can move the “mid-barrel” bead forward or backward, depending on the depth-of-field their eye gives them.

When the job is complete, swing the shotgun up to your shoulder quite a few times to see that the beads are in the proper places and down against the barrel from the shooter’s point of view. If a bead is canted to one side, those ungainly beads with the 8-40 thread will allow you to correct the hole in the direction needed with the larger hole and threads. Of course, we have only heard about this. It will happen to you eventually if you do enough of them, because it’s human nature to get cocky and then humble. We hope you never have to use this trick, but it’s available if needed.