Semi Automatic Pistol Design

Spec Ops Shooting

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1. Magazine latch

2. Hammer airut . Hammer spring

4. Sear

5. Sear spring

6. Receiver retaining lug T. Hammer

8. Firing pin retainer

9. Firing pin

10. Firing pin spring

11. Extractor spring and follower IS. Extractor

13. Rear barrel retainer

14. Barrel recoil spring

15. Slide body

1$. Front blade sight IT. Front barrel retainer

18. Barrel

19. Takedown lock

20. Receiver retaining lug

21. Frame lug

22. Trigger return spring

23. Trigger

24. Disconnector spring/spring guide

25. Disconnector/trigger bar

26. Ejector (behind disconnector)

27. Magazine

In this volume, I propose to show two different pistol (or handgun) designs which can be manufactured in the home workshop.

One of these designs is for a semi-automatic pistol, and the other describes a fallingblock single shot pistol. The first one is of necessity limited somewhat by the cartridge size it must use. My second, single shot design will handle just about any cartridge that is practical to use in a hand- held firearm, provided proper steels and heat-treatment methods are used.

While it is entirely practical to make a revolver in the home workshop if proper equipment is available, I have not included a revolver design in this book. Without professional training and equipment, it is very difficult to hand-build a revolver cylinder that will index and lock up properly.

As with the submachine gun, probably the most difficult part to make for the semiautomatic gun is the clip or magazine. So if possible, a suitable magazine should be obtained or manufactured first, and the frame of the gun then built around it.

The first pistol discussed here is made in .22 long rifle, .32 ACP,.380 ACP, or any combination of these three. In fact, with a magazine for each of the three calibers and a corresponding slide (barrel assembly), the same frame may be used for all three calibers. The pistol can be converted to any of the three calibers in a matter of seconds simply by turning the small take-down lever located on the left side directly in front of the trigger guard. This action releases the self-contained slide/barrel assembly, allowing it to be lifted from the frame and replaced with a slide/barrel assembly in the desired caliber. A magazine of the corresponding caliber is inserted in the frame, and the pistol is ready to use again.

Slide and barrel assemblies made from tubing no doubt will look a little crude. And neither of these pistol designs will ever be considered streamlined. But by the use of tubing in the manner described, I eliminate the necessity of cutting mating grooves along the length of both the frame and slide. Such a grooving procedure is a challenge even to the professional gunsmith with proper tools. Nor do I normally endorse the idea of a welded sheet metal frame. My over-riding consideration here was that such a frame can be constructed with a couple of files, a hacksaw, a few drills, and a few minute's use of welding equipment. So if the design is lacking from the standpoint of appearance, it more than makes up for it in ease of manufacture.

In the event that you elect to make this pistol with the interchangeable slide/barrel assemblies, it will almost certainly be necessary for you to manufacture your own magazines, since I do not know of any interchangeable commercial clips in all three different calibers. If you will follow the instructions in the chapter on magazine manufacture, you should be able to make clips for the different calibers which will all fit into the same frame. I have not incorporated a magazine safety in this design, which means that the pistol will fire with the magazine removed. When engaged, the safety lever on the left rear side of the gun blocks the hammer from contacting the firing pin. This, and a positive half-cock notch on the hammer are the only safety provisions incorporated in the pistol's design. Its firing pin is an inertia type similar to the M1911 Colt .45, which allows the gun to be carried safely with the hammer down without the firing pin striking the primer of a chambered round. So the weapon may be carried safely with either the hammer down, at half cock, or at the full cock with the safety engaged.

Simple fixed sights are fastened on the top of the slide assembly. No sighting adjustment is provided since a short-barreled pocket pistol of this type is usually meant for use only at short range. The sights can be adjusted by filing the front sight to raise the point of impact in relation to the sight "picture," or by filing the rear sight sideways in the lateral direction you want to move the point of impact.

Firing Pin Plate

Retainer plate Stock retainer bolt Hanger

Hammer spring Hammer strut Link Sear Hammer

Falling breech block Firing pin retainer Firing pin Firing pin spring Receiver Barrel Forearm

Forearm retainer bolt Trigger guard Latch

Latch spring Trigger spring Trigger Trigger bar Lever

Grip frame/breech block housing Grip stock

The single shot pistol design shown herein uses an entirely different approach to our problem. Since it utilizes a falling-block design made from solid steel, it will be strong enough to handle just about any cartridge you care to chamber it for. The barrel may be as long as you care to make it. With good adjustable sights or a suitable telescopic sight, this handgun should be as accurate at longer ranges as any other weapon of this general type. Here again I have tried to keep its design as simple as possible. The hammer must be cocked by hand. It could be made self-cocking relatively easily, but this would demand additional parts and machining operations. Or a hammerless, self-contained breech block could be used, but this would call for extra parts plus a safety lever of some sort.

No attempt has been made to incorporate an ejector into this weapon. In most cases it is desirable to retrieve the empty cartridge case after firing for the purpose of reloading. So, in this design, a simple extractor actuated by the lowering of the breech block causes the spent case to protrude from the chamber far enough to be grasped by the fingers and removed. This is preferred by most shooters, rather than hunting the empty case after an automatic ejector has thrown it completely out of the gun.

I seriously recommend that your weapon be machined for rimmed cartridges. Use of a rimless cartridge complicates the extraction mechanism, since a spring-loaded lip is required to cam outward over the head of the case when the action is closed, simultaneously engaging the extractor groove of the cartridge case. On the other hand, the extractor for the rimmed case is of solid one-piece construction, moving only the rim of the case during ejection.

The round breech-block design shown should be used only if the gun is to be chambered for the relatively low-pressured cartridges, such as the .22 rimfires,.38 special, etc. This type is included here simply because it is much easier to build than the rectangular type also shown.

If the gun is built and chambered for any of the high pressure, high intensity cartridges such as the .22 Hornet, .357 magnum, or .44 magnum, then you must use the rectangular breech-block design. It is much stronger than the round one.

My second pistol can also be made to accept several interchangeable barrels in different calibers. Its caliber is changed simply by changing barrels, provided the rim diameter is the same as that of the cartridge the pistol is originally built to accept. A larger or smaller rim diameter will necessitate that the extractor be changed also.

I, personally, have no use for a telescopic sight on a pistol. If you want a long-range weapon, you should build a rifle. My own pistol designs utilize only adjustable iron sights, as shown in the drawings and pictures. Any "sport" who simply must have a scope on his handgun will find that scope mounts made for other handguns are also adaptable to those of my design as well. One last word of advice: read all the instructions and study all the diagrams presented here before even considering starting your home workshop gun. If you thoroughly understand all the procedures and schematics before beginning construction, your pistol will be much easier to build right the first time. I also suggest that you have a copy of Volume One of this series handy for reference, though it is not imperative.

Chapter Two

The Home Workshop

If you have already read the first chapter of volume one of this series, the following information will already be familiar to you. Also, I realize that a good percentage of readers are amateur or professional gunsmiths, gun buffs, or machinists. To them much of this will be routine.

Very few readers will have a fully equipped machine shop at their disposal, nor all of the knowledge needed to run it professionally. Though I do have a machine shop of my own now, just a few years ago I did not. It was then that I learned most of the "home workshop" techniques I present as alternatives to making up your weapon with the help of a machine shop. Here is a list of the minimum tools necessary to build your handgun(s):

A 1/4 inch or 3/8 inch drill motor (or hand type drill)

A hacksaw with several blades

Several eight and ten inch flat mill bastard files

Three-cornered triangular files (small)

Small square files

Center punch


Micrometer or vernier caliper

12 inch ruler


Appropriate taps with corresponding drills Tap wrench

The use of a lathe, welding equipment, and grinder.

One of the most useful home workshop improvisations can be used to form openings or small parts usually made with a vertical milling machine. These include the ejection port, trigger, hammer, sear, and many others. This substitute procedure is started by scribing the outline of the opening or part on a piece of steel of desired width. Drill interconnecting holes around or within the outline (depending on situation), until only a thin web of metal connects the outlined area. Punch it through with a cold chisel, and finish with files.

And I'll add here that you should learn to use files properly and efficiently. Many procedures normally done with a milling machine can be done with hand files and patience, hence the fact that the file has been nick-named "the poor man's milling machine".

"The poor man's lathe," or your electric hand drill, can be substituted for many lathe operations, but is not recommended for accuracy. Here, the part to be lathed is chucked in your drill, and the drill's handle secured in a solid vice. The drill is switched on, and a flat mill bastard file applied as shown in the photo.

All of this , and other alternative procedures covered in the following pages, add up to "jackleg" gunsmithing at its best. Patience can substitute for electricity , and perseverance for elaborate equipment. And remember, there is no reason why your home workshop gun should not be just as safe, accurate, and reliable as a similar mass-manufactured model.

By replacing the pins in the hacksaw frame with longer ones, it can be made to accommodate two or three blade at once. Wide slots are cut far more easily with this method.

Jackleg Drill Repair

Some readers may have a drill press and vice set-up like this at their disposal. Those who have only a hand drill will have to take extra care to insure that the drill is held at right angle to the work.

Ejector Lathe

If no lathe is available, many lathe operations can be performed with a "Poor man's lathe," as pictured here. Though this technique is not recommended for accuracy. It can save you a lot of time and sweat, and produce reasonable results in many cases.

Sterling Design Diagram

These sanding discs were originally designed to serve in an automotive body shop. I mount such discs on an arbor, and use them for grinding and sanding operations. Use masonite, or a similar stiff backplate material behind the disc.

Semiauto Pistol Drawings
- 3.600"-f

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There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

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    How the trigger links to the hammer?
    9 years ago
  • Nerea
    What is a poor mans lathe?
    8 years ago
  • caradoc
    How to properly replace the trigger spring for a SA9 hammerless semi automatic pistol exploded view?
    6 years ago
  • hamid negassi
    How to design semi automatic pistols?
    6 years ago
  • negisti goytiom
    How to make metal sheet single shot pistol?
    3 years ago
    How to design a semi auto only sub gun?
    3 years ago
  • daniel
    What is the purpose of machined slots in a semi auto pistol?
    1 year ago

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