Hi Power barrel change.

[Jim Watson]

In 1942, the 1911A1 had a 4150 barrel, 1035 receiver, 1050 slide.
Small parts from 1020 to 1095, some 1115.

[Dixie Gunsmithing]

Jim,

Do you know how early they made the barrel with 4150? I would think that might be another change too. The slide, I had read about, but don't recall the barrel.

Anyhow, 1035 may be what was used for the Hi-Power slide, I guessed it at 1040.

[Jim Watson]

No, that is a single data point taken from an article in Machinery magazine, December 1942.

http://forum.m1911.org/temp/1911manufacture.pdf

[Dixie Gunsmithing]

That was a good article. I made a mistake above, the slide was 1050. One thing that I caught, is that the list says the barrel is 4150, but the text on page 311 says its a modified form of 1350 (low chrome and manganese steel). Its the right amount of carbon (0.5%), but the difference is the alloying using chrome and molybdenum. I guess they're saying 4150 is made from 1350? By what I read earlier, the 41xx alloy's were a specialty before WWII, back to the 1920's, and was batch made, mainly for DOM tubing, after Mannesmann in Germany invented the process of making the tubing during WWI. The biggest step that I was aware of, was the new use of nickel steel, by Winchester, in the new model 12. That is why I am wondering if the 1911's barrel material may have changed later on, since it was designed before and then patented on 1911, as about everything was made of a hardened carbon steel, or 'armor steel', as LC Smith called it. What that was, or had in it, I'm not sure. It seems that the 41xx steels were newly specified during WWII in military firearms more than anything.

Anyhow, the article shows how the lug recess is cut in the 1911, and I am sure it was done the same on the Hi-Power. That is a tedious bit of set-up and milling.

[Jim Watson]

Yes, look at the work it takes to cut locking lugs on the barrel and abutments in the slide and it is easy to see why later designs went to just a blocky chamber section setting up into the ejection port.
First seen that I know of in the French 1935S.

[tangolima]

The new lock lug, as seen in glock, works much better, in addition to ease of manufacturing, that loose breech becomes a non-issue. The massive block of steel can take a lot of heavy beatings.

-TL

[James K]

I am going to stick my neck out on this one, as it is based on something I think I read years ago. If my recollection is correct, the barrels of both the M1911 and the original BHP started as forgings with the bottom lug (foot) as part of the forging. The forging was then drilled with a small hole to use as a reference point. Then the barrel was faced off, the bore drilled almost to final specs, the outside of the barrel machined to size, and the foot and locking lugs machined. Finally, the bore was rifled and the chamber cut. That is a lot of machining, so it is easy to see why the two piece barrel had appeal.

Two piece barrels were tried in .45 pistols, but there is less material to work with and they were not successful.

Cutting the locking lug seats in the slide necessitated use of a tool that would not fit through a hole the same size as the barrel. That is why guns like the 1911 and BHP use barrel bushings, to fill the gap between the size of the hole needed for machining and the OD of the barrel.

Jim

[Jim Watson]

Has Springfield Inc quit using two piece barrels?
Even if they have, there are a lot of them out there.

I fail to see any advantage of the chunk in the ejection port to anybody but the company accountant.

[Dixie Gunsmithing]

With regards to the engineering standpoint of the lugs, you would have to look at how big one or more lugs are, and how deep and wide the recess or recesses in the slide are, in area (thickness x height), to withstand the separating force of the barrel and slide over the chamber pressure. Here, that force is the same pressure that the barrel sees in bursting. Browning, earlier, tried several locking lug designs, and on the 1911, he used a multi-lug, and on the Hi-Power, he used a single lug. Here, I think if he had at least used two lugs of just a slightly smaller size, than what was used on the 1911, the lug area would have went up, and the gun most likely would not have had any problem with +P ammo. The shear area would have only needed to be increased by 10%, the same as the increase in the pressure. What they did, was make everything as small and light as possible, for the 9mm ammo that the French government was using at the time.

When we look at the new pistols, with the large square chamber, that locking area, in square inches, which fits in the slide recess, has to be equal, or bigger, in total, than the recesses cut into a slide in the Hi-Power and the 1911, according to the caliber and pressure generated. It's also an easy way of making a barrel for one size fits all, in various calibers, so you just design it for the highest pressure round, and they'll all work. Then, the smaller calibers will have an over-kill in lock up.

As far as cutting the recesses in the slide, using a larger hole in the end would allow a bigger spindle to hold the cutters. If you look at how that is done, the spindle is supported at the cutter end by a small center or tailstock, that goes through the ejection port, which takes off a lot of the strain. That is, it looks to me that that is how they did it, as it would probably chatter if not, when any bite of any size was taken. That may have been part of the reasoning of the barrel bushing, but quick field stripping, and disassembly was another, when compared to Brownings older pistols. I think he was most assuredly designing the 1911 with military orders in mind, when he designed it, like he did for the Hi-Power. It was probably a plus for both.

[Dixie Gunsmithing]

I fail to see any advantage of the chunk in the ejection port to anybody but the company accountant.

There is a whole lot of truth in that statement. The machining time is cut way back. They just cut the port recess to give enough lockup for the highest rounds pressure, and they have a multi-caliber pistol with a machining step removed. That is also why you don't see the graceful lines and curves on pistols anymore, where now, they are all square and blocky.

[Dixie Gunsmithing]

Just for fun, I calculated the separating force for the 9mm and the 9mm +P, and using the bullets diameter for the ID of the case at the rear of the cartridge (area = bullet radius squared x pi, then x chamber pressure).

9mm = 3,464 pounds at 35,000 psi

9mm +P = 3,810 pounds at 38,500 psi

[tangolima]

That's static pressure assuming no loose breech. When there is play between the barrel and slide, the force will be more.

Regarding the new type of lock lug design, it is more complicated than just cutting the ejection port big enough. Big ejection port is always desirable for reliability alone, but it also weakens the slide. The original 1911 had tiny ejection port. It only got enlarged much later when better steel was used in the slide. In other words, Browning couldn't do the lug in the ejection port even he wanted to. That could well be the reason "internal lugs" were used even they were such a pita to mechine.

-TL

[Jim Watson]

As far as cutting the recesses in the slide, using a larger hole in the end would allow a bigger spindle to hold the cutters. If you look at how that is done, the spindle is supported at the cutter end by a small center or tailstock, that goes through the ejection port, which takes off a lot of the strain. That is, it looks to me that that is how they did it,

Yes. Look at figure 12 in the 1942 article, caption reads:

Fig. 12. Two Locking
Grooves are being Milled
at lite Top of lhe Inside
of the Slide just in Front
of the Carriage Outlet. A
Small Cutter is Used at
the End of a Long Spindle
Supported by an Arm


The developmental Saive-Brownings that were getting to look like the familiar BHP had 1911 type barrel bushings from 1926 til 1930. Looks like they went to a fixed bushing in 1931 and stayed with it until the design was finalized in 1934.

[Dixie Gunsmithing]

That's static pressure assuming no loose breech. When there is play between the barrel and slide, the force will be more.

tangolima,

Well, you have the same force in pounds, but what happens is that the impact changes. The normal lug clearance wouldn't be very much for a tight breech, but a loose one would have a wider gap, and the impact force raises. A lot of materials, including steel, holds static pressure fine, but impact is the same as a steam hammer dropping that pressure in pounds over those extra thousandths of an inch, or its the same as pounding against the surfaces. Impact is not generally taken near as well like static forces into a tight unmovable fit. Well, I wont say unmovable on a tight breech, more like a couple of thousandths, but the impact really increases with every extra thousandth that is added. Eventually, impact causes them to beat each other farther apart.

Jim,

Thanks, I forgot to read that at the photo, and went off what I saw in the picture itself.

We made a rack gear in a lathe in a similar fashion a long time ago. We put a gear cutter on a two piece spindle, and mounted it between the headstock and the tailstock, and mounted the gear blank on the cross slide. That is pretty much what they did here, just a lot smaller version.

[James K]

Hi, Jim Watson,

Thanks for that article. I hope you don't mind if I print it out as it is a keeper.

But yes, I think you are looking at that picture (Fig. 12) wrong. The machine chuck on the upper left in the photo is turning a cutting head at the end of a long spindle that reaches down into the slide from the front. The end of the spindle can be seen through the partially finished ejection port.

A deep hole drill and an end mill were used earlier (Page 308, right center) to drill the preliminary hole and partly machine the breech face. The final operation on the breech face would be a vertical broaching to finish the cartridge seat; that requires cutting away part of the slide, which is why that square cut in the slide at the top rear of the ejection port. The hole is filled by what is often called the barrel hood. In spite of some neat theories, the real function of the hood is just to close up the hole that was needed in manufacturing.

Jim

[Dixie Gunsmithing]

James,

Yes, that was a great article, which I also saved and printed. Also, there was a set of machine shop books available at one time, through Brownell's, that had a bunch of photos showing the machining process for S&W revolvers, but I can not remember the title. Do you, or any on here know the name of these books? It was similar to Machine Shop Practice, but I can't remember the author or publisher.

Edit:

I found them, and they are; Machine Shop Practice, By Karl Moltrecht, Vol 1 & 2. I think Vol. 2 might be all Brownell's has now.

[James K]

Thanks. IIRC, the Gun Digest once had an article on manufacturing the S&W and one of the old Colt books (Haven?) had similar info on Colt. I also had the opportunity some years ago to visit the S&W factory. It is interesting to learn how things are done at the factory and they are not always done as we think they would be.

For example, the factory uses a bunch of hard, shaped wheels for polishing. At S&W (if they still do it the same way), they have a wheel for each frame size that is shaped like the whole bottom of the revolver. They polish the front of the frame, the trigger guard, and the space back of the trigger guard all in one pass, with just a flip of the operator's hands. Of course making the wheels takes time, but in production, that time repays itself many times.

Jim

[Dixie Gunsmithing]

James,

That is how they milled the pistol frame at one time, according to the books I mentioned. They had a large milling cutter made in the profile of the bottom of the revolver frame, and part of the grip, that would make a cut in one pass. I think that was on a horizontal mill. The also used shapers for some operations, which is something you never see any more. Keep in mind that these photos was pretty old.

There is a company that makes those profiled wheels, but I can't remember the name, only just visiting their website at one time. I think they were either in New Jersey or New York. I have seen some photos, I think from Winchester, that showed a guy polishing barrels, and the wheels they used were probably 16" to 24" in diameter with no profile. However, a lot is done by belt now, and using robots instead of skilled polishers.

[James K]

They call those milling tools gang cutters because several cutting tools are "ganged" on a single shaft. The article on the .45 manufacture shows a gang cutter in Figure 5, milling the tops of five frames at one time.

Here is an interesting factory technique if you hadn't heard about it. The frames of the S&W 22A start as a bar of aluminum extruded in the shape of the frame, then pieces are sawed off, just like slicing bread. The outline is already there and the pieces are then machined to make the frame.

Jim

[Dixie Gunsmithing]

James,

Yes, that's a slick way of doing it. S&W has experimented with many methods. Remember that one gun they made, I forget the model, that favored the old Grease Gun? The magazine well was arc welded onto the receiver tube. They never tried to hide the weld either, like Winchester used to do. I think extrusions create sort of an orientated structure in aluminum, sort of like steel when it comes out of a slab caster. In other words, as it hardens, the structure of the aluminum tries to orient itself in the direction of the extrusion. That may be why they do it, as it may toughen it more than a poured casting, the same as with steel (not grain per say). Plus, it would save a bunch of money, as compared to having castings, as many steps would be taken out. The only problem is having to hog out the innards of the frame.


There was a company that sold aluminum gearing and splined shafting, in different teeth numbers and sizes, which were extrusions. Their add was a cartoon of a guy dressed as a butcher, who was whacking off gears with a butcher knife. They had the extrusion drawn like a roll of Salami.

[James K]

That was the S&W Model 76, a clone of the Swedish Carl Gufstaf Kulsprutepistol m/45, which was inspired by the British STEN, Though better made than the parent STEN, both guns were made to a price and that didn't include cleaning up welds and other such niceties.

I have never fired a Model 76, though it seemed like a pretty good gun in handling. There was a version that fired caseless ammunition.

Jim