.Basic Home Gunsmithing
("...And that's how, with a few minor adjustments, you can turn a regular gun into five
I am using the term “gunsmithing” rather loosely, because without specialized training and skills all we’re really doing is being “kitchen table Dremel jockeys”, which is the firearms version of the shade-tree mechanic. For any complicated or difficult work, you should definitely take it to a professional with a good reputation. For simple stuff, though, you can probably do it on your own. You’ll save some money, and there’s a great deal of satisfaction to be gained from doing your own projects.Reference Materials:
Disassembling a firearm, like any other machine, is typically not at all difficult: re-assembling them is the hard part! It’s important to know where to obtain the instructions and diagrams you need to re-assemble your firearms, before you start. Most gunsmiths can tell you they’ve had more than a few people shamefacedly bring them a Zip-loc bag full of loose parts because they disassembled their gun and can’t figure out how to put it back together.
The owner’s manual is always included with a new firearm, but these are frequently lost when guns are resold (and the very old manuals are rare enough that they are considered collector’s items). You can usually contact the manufacturer to obtain a copy of a manual if you need it, and in fact most manufacturers have a section on their website where you can download a copy of the manual so their customer service departments don’t have to get bogged down filling this routine request. Unfortunately, this only works for companies still in business and where the manual isn’t out of print because the gun was discontinued years ago. Often the manual can be found through Google.
However, in most cases the owner’s manual will only tell you how to do a basic “field strip” for cleaning purposes and how to reassemble it from there, and will contain an exploded diagram and parts list. It can be very difficult to decipher these tiny diagrams. The idea is the manufacturer doesn’t really want the average owner doing a “detail strip” (total disassembly), preferring instead that this job be left to a certified gunsmith for liability reasons. There’s actually not a whole lot of damage you can do with reassembly as long as you follow instructions, don’t try to force anything, and perform a function check after re-assembly before you attempt to fire the gun.
It is often possible to obtain armorer’s manuals for specific guns, which have detailed diagrams and disassembly/reassembly instructions, as well as all of the manufacturer’s maintenance and troubleshooting procedures. Once in awhile you can even find them online for free download.
The American Gunsmithing Institute (AGI) has a superb series of videos, each video dedicated to a specific firearm. A master gunsmith discusses and shows you the gun’s internal mechanisms and function in detail, and demonstrates total disassembly and reassembly. For those of us who learn best by seeing and then doing, these are top notch.
The internet is also a hugely useful resource. Start by searching Google for the gun and the problem you’re having with it, for example “Ruger 10/22 jamming” or “1911 reassembly”. The more popular models of guns will have at least one big website devoted to them, and these will usually have disassembly/reassembly guides with photos that far exceed the helpfulness of your owner’s manual. You can sometimes even find instructional videos for disassembling your gun on YouTube if somebody’s bothered to make one, so this can be worth a look. Although production values are subpar, seeing it done might just show you the solution to something that’s been stumping you.
One of your greatest resources for getting clarification will be forums. Popular gun models each have entire discussion forums dedicated to them, and there are plenty of other firearms-related forums where you can ask specific questions about any gun and probably get an answer from at least one person who has dealt with your problem or at least understands the topic well. Be sure to use the forum’s “search” function to see if anyone has asked your question already, and take a look at the “stickied” posts that are set to always stay at the top of the list of recent posts because they usually address frequent topics. You should do this because we gun nuts are an opinionated lot, and seeing the same questions innocently asked every week by new members can stir up a lot of nerd rage.Spare Parts Sources:
If the manufacturer is still in business, they might be your best bet, but they probably won’t be the fastest.
Between Brownells and Numrich Gun Parts, there aren’t too many spare or replacement parts you can’t find. As a last resort, a skilled gunsmith can fabricate most small unobtainable replacement parts such as springs, extractors, etc.Iron sight adjustment:
I classified sight adjustment under home gunsmithing, but really it’s a minor procedure that is done with a simple tool (sometimes specific to the gun or type of sight) at the range or in the field, where proper alignment can be tested and dialed in through trial-and-error with a target.
Unless you are a fantastic shot (and if you are, you very likely don’t need to be told how to do this), dialing in sights should be done from a shooting rest, to minimize the movement of the gun as much as possible. Pick a range at which you want the point of aim (what the sights are aimed at) and the point of impact (where the bullet actually hits) to be the same. This is known as the sight’s “zero”. A common zero range for a rifle is 100 yards, but as you become more adept at shooting you may find that you want to increase this range. For a .22, a common zero range is 50 yards.
For handguns (which generally do not need adjustment unless the sights are replaced), 25 yards is a reasonable zero range. Handgun sights are typically held tightly in a dovetail cutout in the slide, and are difficult to move. You could tap them out with a brass punch and hammer, but the best method is to use a specialized sight adjustment tool, appropriately called a “sight pusher”, that resembles a vise clamp. They are sometimes sold specific to one model or brand of handgun, but universal ones exist.
One important note here is that sight pushers will probably not work on a Springfield XD pistol, because Springfield makes the fit so tight that they have to install the factory sights with a press: you can remove the sight by making a relief cut with a cutting wheel, but this doesn’t help with the problem of only adjusting the sight or installing a new one. Sight replacement or adjustment on XD pistols is a task for a gunsmith with the expensive equipment to do it properly.
To zero: A target, preferably one with a grid, is shot three times from the distance you wish to zero and then examined. If the holes are very close together but not centered, you know this was a good test and you now know in which direction you need to adjust your sights so that POA and POI line up. If none of the holes are close together, it may be the ammo or it may be that the bore or crown are damaged, but it’s much more likely the fault of the shooter.
If the rounds aren’t hitting the paper at all, repeat the test by aiming for the top of the page, then the bottom, and each side if necessary to determine where the rounds are going. If you remain stumped, move the target in closer. Once you’ve figured out in which direction the sights are off, adjust their POA for windage and/or elevation as required.
To move the POA of iron sights, either move the front sight in the opposite direction or the rear sight in the same direction. For example, to move POA to the left, you must adjust the front sight to the right or adjust the rear sight to the left. You can remember this with the mnemonic “F.O.R.S.”, which stands for “Front Opposite Rear Same”.Scope installation:
Installing a scope isn’t a particularly difficult procedure, there are just a couple things you need to take care with. You could buy a “scope mounting kit”, but these aren’t a great use of your money. The only tools you need are an appropriate screw-driving bit, and something to degrease with (non-clorinated brake cleaner which you should already have in your kit works very well, as does acetone with a rag). A torque wrench (at 30 pounds per inch) is helpful if you already have access to one so you don’t over- or under-tighten, but isn’t required. You will also need a tube of blue thread-locking compound such as Loctite (I prefer the gel because it’s much easier to work with than the liquid).
Loctite is very important because firing a gun subjects the parts to a lot of shock and vibration, so unsecured screws have a strong tendency to loosen. More is not better, though, because excess Loctite will just be squeezed out and make a mess. Use blue Loctite, which is medium strength and removable: do not use red Loctite, which is permanent.
The most important thing is to buy quality rings and a quality mounting platform. Cheap rings and rails are made of low-quality steel or aluminum, and they will break loose, peen out, or otherwise fail you eventually. When the gun is fired, it moves backwards under recoil and the scope’s inertia means the rings are pressed into the scope rail. Soft metals will be peened by this battering, eventually loosening the ring’s hold on the rails and allowing the scope to slop around. When your scope moves even a little bit, so too does your point of aim. A set of quality steel scope rings that do not allow the scope to move will cost you $50 to $100 or more, which seems like a lot but they are the only ones that can do the job and they are a one-time purchase. Beware of the old-style Weaver rings that only have tightening screws on one side, because they will rotate your scope towards the screws when tightening, no matter what you do to try to prevent it.
A cautionary word here on scope screws: the two sizes used for mounting scopes to firearms are pretty much not used for anything else. If you lose or damage a screw a replacement isn’t hard to order, but don’t count on finding it at your local hardware store. If you get a screw at the hardware store that looks like it might fit, chances are you’ll get it stuck and mess up the receiver’s threads in the process. Traditionally a 6-48 screw has always been used for mounting scopes, but the reason this thread was chosen was probably lost to time and nobody except those in the firearms trade uses it. Custom gun makers typically use larger 8-40 screws to secure scopes to rifles, because they are much more suitable for standing up to the recoil of harder-hitting cartridges. Gunsmiths will occasionally drill out old 6-48 holes with an 8-40 tap, and many believe that all of the manufacturers will eventually come around to using the larger and more suitable 8-40 in the first place.
Before starting, be sure to degrease all the screw threads, the scope base, the mounting holes in the receiver, and inside the scope rings. After degreasing, it’s helpful to apply powdered rosin or some silicone (not silicone-based lubricant!) to the inside surface of the scope rings where they will contact the scope tube, to prevent the scope from sliding. Some rings come with a non-slip coating on the inner side already.
First, you need to install the scope base. If your gun doesn’t have holes to mount a scope base, any gunsmith can drill and tap screw holes into the receiver for you. If your gun already had a scope base installed when you bought it, you should remove it, degrease the base and the screws, and perform the following procedure to ensure that it will stay put for you.
If this is a new scope base, if there’s any possibility you may have lost track of which screw was where, or if the base was installed by somebody else and you don’t know for sure they didn’t mix up the screws, start by screwing the scope base onto the receiver without using any Loctite, and work the action to ensure that the screws do not interfere with its movement. Some mounts have screws of differing lengths to accommodate thicker parts of the receiver: ensure that you’re using the screws in the correct places so that the longer ones don’t protrude into the action and interfere with the movement of the bolt. Once you’re certain everything is properly arranged, one at a time remove each screw and apply a small amount of blue Loctite to its threads, then re-insert the screw most of the way. After all of the screws are most of the way in, go back and tighten each one a little at a time so that the base is tightened down evenly.
Do not over-tighten the screws! The most common mistake made in scope mounting is to torque the screws down as tightly as possible. Conventional wisdom says to screw them in as tightly as you can, and as is often the case with conventional wisdom this is wrong
. There are two very good reasons not to over-tighten. Firstly, by tightening the scope down more than it and its mounts were intended to be tightened, the tube of the scope is flexed: this alters your point of aim. Secondly, the threads are subjected to much more stress than they are capable of withstanding, and sooner or not much later they will fail and the screw will come a little loose: conventional wisdom blames this loosening on not having had the screws tightened down enough
, and consequently this poor practice is reinforced and the mistake repeated. The screws should be snugged down, but only to 30 pounds-per-inch of torque: you should not feel like you are straining your wrist and forearm to tighten them. Since you’re following these instructions and using Loctite on the threads, you won’t have to worry about the screws coming loose until you’re ready to take them off yourself.
If necessary, you can tweak the scope’s alignment by shimming the base and/or the rings: appropriately-sized shims can easily be cut from an empty aluminum drink can. You want the scope to be centered and aligned with the bore as much as possible, so that extreme corrections will not have to be made with the scope’s dials later.
Next, attach the bottom portion of the rings to the scope base. Lay the scope on the rings, then look through the scope to ensure that the eye relief is correct. To obtain proper eye relief, be sure your cheek is positioned on the stock exactly where it will be when you shoot (known as a “cheek weld”), or your scope will be in the wrong position when you get it to the range. While looking through the scope, move it forward a little at a time, until the image starts to darken at its circumference: when this happens, move the scope back just a little bit until the image is clear and bright again.
Also ensure that the reticles are level: a scope that is canted only a couple degrees will move your point of aim at any distance. A vise (with non-marring jaw inserts) is very helpful for this, but a couple of sandbags work nearly as well. Optionally, you can also buy an inexpensive scope level to assist you with this (pictured right). When you’re fairly sure the scope is where you need it, lay the top half of the rings on and install the screws just tightly enough that the scope won’t move while you pick up the rifle to double-check things.
Now shoulder the rifle and gain your cheek weld as you would when firing, to verify scope placement. You may have to make some adjustments. When everything is aligned, put the rifle back in your vise or on your sandbags. Now just like you did with the base, one at a time remove each screw, apply a small amount of Loctite to the threads, and replace it most of the way. After each screw has been Loctited and replaced, tighten down each screw a little at a time so that the rings are clamped down on the scope evenly. Tightening them unevenly can turn your scope a little bit, and you probably won’t discover this happened until you’ve finished.
If you’re using a base with many mounting points, such as a Picatinny rail, try to get the rings close as you can to centered on the scope tube for aesthetics, but aesthetics are secondary to proper eye relief and sight picture. If your base has only one mount point, the scope will have to be moved forwards or backwards in the rings to obtain proper eye relief.
If your gun is a type where you can open the action and peer down the bore, you can “bore sight” it by roughly aligning what you see in the bore with what you see in the scope at a distance of about 25 yards. Then when you take it to the range, start by zeroing the scope at 25 yards and your shots will be on the paper from the start, making the zeroing process go faster. Then zero the scope out to the range you want.Mounting a scope on Picatinny or Weaver rails:
When placing a scope that already has rings attached, move it forward on the rail one slot at a time until the image begins to darken at its circumference, then move it back one slot. Press the mounts as far forward in the slot as you can, and tighten them down. The reason you push them forward is that the scope’s inertia when you fire the gun will make it stay put while the gun moves backwards, so by pushing it as far forward as it can go, the scope’s position will not be able to shift forward despite repeated firing.
If you have a Weaver rail that only has a few slots, you will have to adjust the position of the scope in the rings using the procedure described above.Dovetail vs. Weaver vs. Picatinny rails:
Many firearms have (and just about any can be drilled and tapped to accept) mounting rails made to fit the contour of their receiver. Some of these rails are specifically made or contracted by the firearm’s manufacturer, while others are completely developed and sold by third parties as aftermarket accessories. In either case, they allow you to mount scopes or other accessories using standardized attachment rings.
Some accessories use a dovetail rail (see Fig 1). They rely exclusively on a binding force provided by tensioning screw which pinches the mount onto the lips of the rail. These are typically only seen on airguns, but I mention them because you might see them on some cheap accessories, which is an excellent sign to avoid that accessory. A dovetail rail is not suitable for standing up to recoil. Worse, you have no way of knowing if your scope has been knocked forwards or backwards unless you’d painted or scratched a mark on the rail, and it is very difficult to place the scope in exactly the same position if you have to remove it. You’re more likely to see a dovetail with an improved design that also has a cross slot to prevent the mount from sliding forwards or backwards.
Both Weaver (see Fig 2) and Picatinny (see Fig 3) rails are similar in their basic principle to the Dovetail, but the rail is flatter and wider, and there are cross slots to prevent the scope from shifting forwards or backwards. The main difference between Picatinny and Weaver rails is the width and distribution of the slots.
Weaver slots are 0.180 inches wide, but there is no standard for how many slots there will be: many weaver rails have only few slots (as pictured), while others have an even distribution along the entire rail’s length. Weaver rails are often (but not always) zero-hold, meaning that any optic you remove and put back on is able to be mounted in the same place so you don’t have to re-zero the scope.
Ruger firearms use a proprietary rail that is very similar to the Weaver design.
Picatinny rails were originally developed in the 1980s, but became standardized for the US Military by the Picatinny Arsenal (as Mil-STD-1913) in 1995. Picatinny slots are standardized to always be 0.206 inches wide and 0.118 inches deep, spaced 0.394 inches apart. The slots provide maximum flexibility in positioning options, as well as allowing the rail to expand without distorting its shape when it becomes hot. Picatinny rails are required to be zero-hold.
Some mounts are designed to attach to both Weaver and Picatinny rails, but a mil-standard Picatinny mount will not fit on a Weaver rail. Barrel break-in procedure:
The practice of “breaking in” a new barrel is controversial, with very strong opinions on both sides of the issue. The idea is to fire specially designed, progressively less abrasive rounds a few at a time, carefully cleaning the barrel between every few shots, in order to smooth out the bore. Competitive bench-rest shooters who subscribe to this practice believe that it increases consistency to improve accuracy.
For average shooters like you and I, we will never see any useful accuracy gains by doing this. In actuality, a bore that is totally clean is not consistent from shot to shot, because it will become progressively more fouled after the first round. Consistency is achieved under normal shooting conditions just by having a little fouling in the bore that fills in tiny imperfections.
What is certain is that by using abrasives to smooth out the sharp edges of the rifling, you are deliberately accelerating the wear process and dramatically reducing the usable life of your barrel. This is great for barrel makers because they get to sell more replacement barrels. Breaking in a “match barrel” is a waste of time, because you already paid a premium price to get a barrel that was carefully made to be smoother than a mass-production barrel. Custom barrel makers include instructions on a break-in procedure only because many of their customers insisted that they do so.
If you are capable of shooting very tight groups out past several hundred yards, where your group sizes are competitively measured in thousandths of an inch, then you don’t need my lowly opinion on whether breaking in a barrel is worth the trouble and you should continue doing what works for you.Trigger jobs:
I mention trigger jobs only to encourage you not to attempt them. The idea is to smooth out a gun’s trigger pull by sanding and polishing the surfaces where the hammer and seer interact. This should not be performed because internal gun parts are surface-hardened, and when the surface hardening is sanded away the parts will wear out much sooner. Additionally, altering the geometry of these pieces in any way can easily result in a gun that fires when dropped or jarred, obviously creating a gun that is very dangerous to use or carry.
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