How difficult would it be for an individual to "make" a high quality gun?

Factual Questions
1

As a spin off of this thread “So what if I want to make a gun?” asking about the legal ramifications of home made firearms. I was curious about the specific technicial difficulty that would be involved in a person making a firearm with regular basement workshop/hobby level machine shop tools. It would have to be able to use regular ammo and be capable of fire multiple shots reliably and precisely.

Given the precision required is crafting a decent, high quality modern firearm beyond the ability of a skilled hobbyist or weekend machinist?

2

You would have learn how to heat treat steel and purchase a furnace, or else send the parts out to be done. If you were making a rifle you would have to purchase a gun drilling machine.

3

You can’t just buy steel that would work?

4

You do not need to have foundry, forging or heat treating facilities to make a gun as many, such as custom benchrest rifles, are machined from billets.

astro, the question is impossibly broad to give a simple answer to. If you have reasonable shop skills and tools yes, you can build a gun but that is no more meaningful than saying someone who builds a lean-to out of branches has built a house. I’ve engaged in much mental masturbation, err thoughtful discussion on this topic with a friend. You may know him. His picture is in the dictionary under “man who cannot swing a wrench to save his life.” He could possibly build a gun but I’ll be in the bunker when he test fires it.

In all seriousness the friend wants to design a centerfire rifle and make it cheaper than a Chinese SKS by “cutting corners” on materials and manufacture. Peak chamber pressures in common rifle cartridges can run upwards of 60,000psi. That’s fine if you have adqeuate materials and precision construction but if the headspace dimensions is a few thousandths of an inch too large a gun can explode like a grenade when fired.

Can Handle the Truth, I assume that “gun drilling machine” means deep hole drilling and cutting rifling grooves in a barrel. Not trivial but there are relatively small shops making barrels. Not common tools for sure. You can buy barrel blanks which are essentialy bar stock with the bore and rifling already cut. IMHO someone who starts there and does all the lath cutting and chamber reaming is building “from scratch.”

You could build a gun without a lathe or milling machine provided you were willing to buy some parts off the shelf. Even simple wartime designs like the Sten required machined parts.

5

I’m assuming the workshop has a lathe, welder, and whatever others goodies a metal machining geek might be able to reasonably purchase with a middle class or upper-middle class income. I was really wondering if all those tiny little pieces you see in the exploded diagrams of revolvers and automatics could be replicated at home and assembled into a working gun, however, I do see your point about it being an overly broad question.

Thanks for the input!

6

fewer and fewer people in our society has the ability to ‘make’ anything from scratch nowadays, with schools and colleges closing down their metalwork departments because they are worried about being sued, and most manufacturing industries that make useful mechanical things shifting overseas.

7

IANA Gunsmith but I was a manufacturing engineer in an army ordnance plant for about seven years. Assuming the kind of stresses that these little parts must endure, I don’t see how they could be machined out of mild steel and survive more than a few shots. If we’re talking pressures of 60,000 psi (per Padeye) that’s approaching the yield strength of most common types of cold-rolled billets and way beyond that of hot-rolled. To make a “high quality” gun I would want some of those parts heat treated and some case hardened depending on the application.

8

Also, IIRC they ended up hard-chrome-plating the chamber of the M-16 in order to fix the jamming problem. If you wanted to replicate that hardness in steel, without the chrome plating, it would require heat treating and would be almost impossible to machine; you’d have to rough machine a mild billet, get it heat treated, then grind it to exact size.

9

So how did pre-high tech metallurgy rifles and pistols like Colt dragoons and Peacemakers and Winchester rifles stand up to hard wear & tear in the 1800’s if these metal hardening techiques were not available?

10

Heat treating has been around ever since steel has been around. I’m sure you’ve seen movies of swordsmiths quenching the hot blade in water. Case hardening is also an old process in which carbon from the furnace charcoal is absorbed into the surface of the steel. These processes aren’t necessarily high-tech.

11

Can Handle the Truth, who said anything about using mild steel for a centerfire rifle reciever? Of course this is something my friend may have tried to do so I should have pointed it out a a reason appropriate engineering is required. It’s also not a correct assumption that chamber pressure has a 1:1 relationship with required material tensile strength. Steel rarely fails in compression so we need to look at how the force is distributed to the walls of the barrel and reciever and the shear area of the locking lugs.

A multi purpose machine like a Smithy which functions as a lathe, vertical mill and drill press could certainly be used to make a quality firearm but someone who has his chops down. If you were making a one-off design all those little bits would probably be easiest to make by hand. I’ve often thought it would be hoot to actually design and build something totally original but haven’t decided what I’d like to design.

12

A chrome plated chamber and bore is a nice feature for wear and corrosion resistance but millions of rifles get by just fine without it. There is no need for rifle barrels to be so hard they can’t be machined. The chrome plating just makes cleaning easier. Barrel threads are cut with ordinary lathes and chamberers reamed with a simple hand tool in every gunsmith shop I’ve been to.

Military rifle recievers like the '03, M1 and M-14 were forged and case hardened but that is not common practice anymore as it is unneeded with modern, alloy steels. Modern semi-auto versions of the M-14 are made with investment cast recievers which are in many cases stronger than the forged originals.

Those 19th century weapons were all designed for black powder which has much less energy than modern smokeless powder and produces a different pressure curve. Even then they did break down with some frequency as the steels weren’t equal to modern steels even with heat treating. The Walker was at the limits of its design even with black powder. The cylinders can hold 60 grains of powder which made it the most powerful handgun available until the .357 magnum as introduced 88 years later. It also wasn’t unknown for a Walker to just blow up when fired because of the big charge. Later models such as the dragoon were made with a slightly shorter cylinder that could not hold as much powder.

I have a modern reproduction Walker which is safer to shoot with a full charge but I only do so when showing off. It’s really, really fun. :smiley:

13

I’m just giving words of caution. Like I said, IANA Gunsmith.

14

How high-quality do you need? Loompanics, ever the publisher of strange information, has at least one book on homemade guns if you are interested. Looks like the book sticks to shotguns, though.

15

Darn you to heck! I was going to mention Loompanics.

In my last Loompanics catalog (which was seven-eight years ago) one of the books they offered had a “universal plan” that allegedly could be scaled down to .22 or up to .50. If I remember the blurb, the claim was that anyone with “average skills” and a “home workshop” could do it, but I don’t know what values they were using for “average skills” or “home workshop”.

16

My friend Paul, a very very skilled craftsman, especially interested in art, and metal work.

He makes knives out of files. He uses workshop tools, and a very small gas fired forge in his garage. He used to make guns, too.

I saw his “replica” of a Colt .44 cap and ball six shot pistol. It was not only functional, but also extraordinarily beautiful, and was made from steel stock in his workplace inventory. He made it all by himself, in his garage workshop. While I will admit he does own a lot of tools, he makes most of them too. He made replicas of flintlock, and caplock muskets, and the famous “Kentucky” Long Rifle. He assured me he could make an AK 47, although he didn’t have plans for one.

By the way, his trebuchet was a fantastic melding of form and function, and looked more like fine furniture than medieval weaponry. The cannon, on the other hand was starkly pragmatic, and as ugly as it’s designed purpose. (It did work, though, and would probably have sent it’s projectile several miles, if Paul had tried to do that.) The biker gang that stole it overcharged it relentlessly until they exploded the breech, wounding two of them.

Mostly, Paul makes three-dimensional shadow boxes out of glass, metal, and an eclectic assortment of unexpectedly beautiful things he found, or made. He also rescues box turtles from the roadside every year, and lets them hibernate in his refrigerator. I kind of miss Paul. He moved away some time ago.

Tris

“We are what we repeatedly do. Excellence, then, is not an act, but a habit.” ~ Aristotle ~