gunsmithing education

[riverman]

I was wonering if anybody had any opinions about gunsmithing schools and education. From the research I have done I have narrowed down my choices to the Colorado School of Trades and Trinidad Community College. I would appreciate any feedback on these schools.
Thank you,
Riverman

[11xray]

I am a graduate of CST. You will get a fairly solid foundation in basic gunsmithing skills, preparing you for entry level job placement within the industry.

Some of the instuctors are better than others.

I only asked one question pertaining to firearms while I was there that I did not get a satisfactory answer to, and it is a killer of a question, which I still do not have an answer to, having asked maybe 25 to 30 gunsmiths.

They do not know everything about every firearm, no one does of course, but they will always make the maximum effort to provide answers to your questions.

If you shoot NRA Highpower Service Rifle competition, one of the instructors was the Pacific Fleet Champion more than once, I think. If there is anything he does not know about shooting service rifles, I do not have any idea what it would be.

One small piece of advice: The better you are at handwork before you get there, the better off you will be.

Let me know if you decide to attend. I am still in the area, and will be for a few more months.

Good Luck

[James K]

OK, 11xray, I'll bite. What was the question?

Jim

[11xray]

Mr. Keenan, it is a question rooted deep in the murky depths of those twin voodoos of interior ballistics and metallurgy.

Is there any way of determining how much pressure a particular firearm will contain safely?

There are SAAMI specs for safe cartridge pressures, but no way of knowing if a particular firearm will handle a certain amount of pressure.

For example- Lets just say for a moment that I was silly enough to go to all the trouble of chambering an M-1 Carbine for a .223

Is it going to come apart when fired? Yes? No? Maybe?

We all know that a 98 Mauser may be safely chambered for a .30-06, providing Rockwell hardness is up to specs.

Yet the .30-06 rates at 48,000 cpus while the 8mm only rates at 40,000.

Conventional wisdom says that this is an unsafe practice, that a rifle should never be chambered for a round with more pressure than the round for which it was originally designed. This is certainly a sound policy to persue in instances of uncertainty.

But how do we know what is safe and what is not in instances which have never been attempted before?

Gen. Hatcher did some work along these lines, but to my knowledge no one has ever proof tested rifles the way SAAMI does with cartridges.

Other than actually blowing up a rifle, is there any way of determining safe chamber pressures?

In the above example of the converted M-1 carbine, where the .30 carbine round has a SAAMI rating of 40,000 and the .223 is rated at 52,000 (IIRC), I certainly would not wish to be the first , or even the second, third, fourth or fifth person to fire that weapon. And it may be every bit as safe as Bill Rugers Mini-14.

How do we know that, though?

That is my question.

Incidentally, there is a reason that this question came to me, but that could be a whole other thread

Disclaimer: I am not suggesting that anyone be foolish enough to chamber a rifle for a cartridge with a higher chamber pressure than it was originally designed to accept. It can be a recipe for disaster. I give you the 96 Mauser as an example. Chamber it for .308, and you will probably be severly injured or even dead the first time you fire it. It is a major NO-NO.

Be safe.

[C.R.Sam]

Nature of the supporting structure.

Physical dimensions
Spec of the material.
Shape of the material.
Peak pressure of the load.
Area of the cartridge case containing the load. (base and walls)
etc etc.
Computable.

And, always proof test.

Sam

[4V50 Gary]

In a semiautomatic firearm, also consider the pressure levels it was designed to operate within. That's something that the engineers should be able to explain both in regards to safety and reliability. For mil-spec rifles, they are designed to operate within the specifc pressures generated by the designated cartridge. Change something, like the caliber and the engineer has to address pressure levels again. Can it safely operate with this new pressure and still be reliable? Changing the barrel length also affects timing (faster unlocking, faster reloading) and again the issue of reliability comes up. The gun may require slight re-engineering to slow down the unlocking.

Want a bad example? Remember those 16" barrels that came out for the 1911 Colt? They were made so as to legalize the detachable shoulder boards that were coming out in the early '80s. Bob Dunlap told me that the guns he saw didn't work. It was too much mass for the cartridge. A good example is Beretta's re-engineering of the Garand to a shorter gun. They didn't just shorten the barrel but redesigned the op-rod in two ways. First, it was straighter (wouldn't pound the gas-cylinder to pieces like a bent op-rod would) and secondly (I may need confirmation on this), the helix cut on the op-rod was changed to impede the unlocking function. A few thousandths of a second slower, but enough so that the bolt doesn't slam back so violently so as to crack the receiver.

Returning more directly to your question, find the engineer's tolerances level for a particular gun and then consider the specs on the involved cartridge. Like Sam says, it's predictable, but you've got to have the info at hand. BTW, make your pilgrammage to Springfield Armory National Historic Site and enter the Holiest of Holys.

[4 Eyed Six Shooter]

I too attended Colorado School of Trades. It was the most fun that you can have with your pants on (at least once you get thru basics). The school gives you a good basic knowledge of gunsmithing. I found that the more that you put into it, the more you will get from it. You can go in just about any direction that you want once you get in the final phase. Before going to school, I found a gunsmith that I offered to work for free for just to gain knowledge. I worked in his shop one or two days a week for 4 months. This gunsmith had attended CST also. He tought me a great deal before I went to school. I found it to be a great help once I got to CST. One tip, you can buy your tools thru the school and have them included in a student loan, but many of the tools can be had for far less money if you get them elsewhere(especially the tool box). You can request a copy of the tool issue list from the school and get them yourself if you wish. Invest in a Brownells draw filing file also. You will do alot of filing in basics and the Brownells file makes it far easier. A good gunsmithing library helps also. Another thing that I did was when I got to the repair phase of the course was to ask the lead instructor to give me the toughest guns to fix. You will learn more if you go for the jobs that are the real bastards. The more difficult the repair, the higher grade you will get if you correctly repair the firearm in a minimum amount of time. Put a little money aside as Glock, S&W and Remington all offer armor courses that are available to you at an additional cost while you are at the school.
Good Luck to you- John K

[James K]

Hi, 11xray,

First off, the 7.9 S and sS ammunition is rated at 49-50000 PSI, not 40,000. The 40k figure would be right for the old 7mm, 7.65 and similar rounds.

As for the question of steel strength, it is not really too murky, just a question of asking the right people. The steel company engineers can provide yield strength, elasticity, and failure points of any of their steel products, which is what the firearms designers use to decide what steel to use in a given application. I am no engineer, but I have seen those figures and the only thing hidden is that gunsmiths are not metallurgical engineers. (Some are not even gunsmiths, but that is another story.)

Figures are also available for the different ways in which that steel may be used, such as casting, forging, machining, etc.

Of course, any designer will want to do what goes by the fancy name of empirical testing, which means you try to blow the gun up and see when it lets go.

To adequately make the detemination with an existing gun is much harder, since there is no non-destructive way to tell what kind of steel is in the gun. If that is known (as it is with WWII military contract guns), finding the yield point should be a matter of calculating the thickness of metal and applying the figures for that type of steel. Those figures do become murky with Mausers, which were made in a dozen countries using steel of a quality unknown even to the makers.

Even manufacturing defects (air holes or inclusions, for example) can be found with x-ray techniques developed for the aircraft and automobile industries. Of course, the cost is high, but you didn't mention that factor.

All guns are over-designed and heavier than necessary, not only for safety, but also for human engineering. You might make a .460 Weatherby that weighs two pounds, but you would probably not sell many, and there would be a lot of 19 round boxes of ammo around.

The little S&W revolvers made with Scandium and Titanium are already beyond the comfort level for anything but an emergency situation, which means the owner may well face a deadly force situation having fired only one or two shots from the gun. This is not, IMHO, very good.

FWIW, I don't think the carbine would have any problem holding .223 as far as the strength of the action and barrel go. Remember, PSI is a convenient means of talking pressure, but a round like the .223 has a lot less "SI"'s than a round like the .30-'06, and it is the total "P"'s that must be contained. The .30 carbine round was copied from the old .32WSL and was never intended to come anywhere near stressing the guns.

Jim

[11xray]

C.R.Sam- I had thought that it would be computable myself. I was interested in a way of arriving at a precise number, but no one seems to know how to go about it, certainly not me. It turns out that the best we can do is a best guess estimate.

We are fairly well aware of the properties of steels by this time- tensile strengths, plasticity, heat treating methods, hardness,etc.
Further, we have an extensive amount of information about some rifles, some from armouries, some from manufacturers and quite a bit from trial and error anecdotal history.
And of course we have cartridge case dimensions and properties. In short, all of the factors which you mentioned.

Nonetheless, in the end, it remains a guess-a well educated, accurate guess, in many instances, but still a guess.

It may be that the problem is my own lack of formal engineering education--I may have to remedy that.

Aside from that , however, remains the fact that Joe Gunsmith, while usually fairly intelligent and resourceful, is not typically the best educated individual in the world.

It would be nice if SAAMI or some other organization would continue Gen. Hatcher's work and provide a aready reference, as is available for cartridges.

I would love to do so myself, but simply do not have the resources at this point.

Mr. Keenan, it could be that I am indeed wrong about that 8mm pressure level- it was not taken from a SAAMI publication.

4V50 Gary, I would love to visit that particular National Historic Site- it is on my list of things to do this lifetime.

I would like to thank the three of you for your interest and information provided on this thread- It has made me think, and I always like that.

P.S.- What does it take to blow up a Ruger? C-4? Composiiton B? A whole other thread unto itself, that.

[James K]

Hi, 11xray,

The pressure level for the 7.9 came from Olson's book, but it is the same as I have seen elsewhere. As I have mentioned before, I knew a fair number of WWII vets who had been shot with 9mm or hit by shell fragments, but I never knew any who had been hit in the body by a 7.9.

As to Rugers blowing, they can, just like any other gun. Because the receivers are cast, Ruger builds in extra thickness and the result is a tough gun. I know of one .44 Magnum Blackhawk that came apart but it was no reflection on Ruger. The idiot owner had read about duplex loads (two different kinds of powder) in a gunzine and decided to go one better and use a triplex load with three different powders. I don't know what the pressure was, but it blew the whole top of the cylinder out (3 chambers) plus no one ever found the middle of the top strap.

Jim