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Building the semi auto MP-44 part 4

Chuck — Tue, 03 May 2016 08:00:19 +0000

This post deals with just one of the small stampings that goes into making a MP-44. he part being make for this post is the sheet metal reinforcement for the back of the magazine well. This simple part closes the rear of the magazine well, strengthens the rear of the magazine well, addes extra support for the magazine catch area and provides a guide for the magazine.

This is what the part looked like after being removed from a torch cut receiver. There is not much there that is useful, however with a little work a new part can be made.

The first step is to measure out the part and then design a female stamping die that will meet the contours of the part.

Once verified it is time to move onto the next part

In this case the next part is the male die. As this process is being accomplished a number of stampings are done.Generally nothing happens correctly the first time.

Now the die is added to. The complexity of the die either requires a cnc machine to make it or a fabricated die has to be made. Due to the lack of cnc yhe die was pieced together to form the required shape.

After the stamping dies are completed then it is time to work out through trial and error the proper shape of the blank.

Not comes the moment of truth. If everything works properly then a good part will be made.

It took a great deal of work to design and make the press tools that were necessary to make just one simple part.

Looking at the Stevens Little Krag rifle

Chuck — Thu, 11 Feb 2016 08:00:53 +0000

The little Krag rifle made by Stevens gun company is a 22 caliber boys rifle. The Krag name was chosen because the Spanish American war was still in the recent memory of most Americans. It is a simply design single shot rifle that came out in March of 1904. The rifle came with a standard 20″ round barrel and oil walnut stock. For a short time there was a scope that was available, it however was dropped after being made for only one year. By 191o the rifle has run it’s course and was discontinued.

Close up of the receiver in the stock.

Out of the stock.

The barrel is a slip fit that is held in with a screw on the bottom of the receiver with a screw.

As you can see from the pictures this is a very basic receiver.

Even the trigger and extractor are of a very simple design.

The bolt as well is very simple in design and function. The bolt handle is what keeps the action closed when the rifle is fired.

There is an interesting design with this rifle. It is the design of the extractor. It is a spring loaded design. Here are a few pictures of the spring and extractor set up.

As you extract the cartridge out of the chamber the extractor springs forward to all another cartridge to be fed into the rifle.

This is a video of its operation.

Quite often I am e-mailed about I am interested in making my own rifle but I don’t have the experience or the tools. This rifle can be made with a very little experience and tooling. There is no or minimal heat treating involved with this design and steel selection could be basic scrap steel.

Interesting single shot pistol

Chuck — Wed, 03 Feb 2016 08:00:28 +0000

Once again Axel , a friend of gun lab, has found another interesting and unusual weapon. This time it is a single shot 6mm pistol. I just wish it was available here in the states. It is the Pistolet Le Moustic.

An interesting design

Single shot lifting breach pistol

Over all size

They even had a holster design for it.

I would really like to study this one closer.

My favorite Maxim machine guns

Chuck — Tue, 12 Jan 2016 08:00:53 +0000

There has been a number of articles and write ups on the Maxim gun lately so I thought I would add my 2 cents in. I have owned a number of Maxim guns over the years. An 08, 08/15 and a Chinese type 24 and well as a number of kits. However, my favorite Maxim guns are the little sales sample that Mr. Maxim use to take with him, the Finish m/09-21 and of course the Argentina brass Maxim. This write up is about the one I like the most and will never own. The Sales sample Maxim in 7.63×25.

This first four pictures came from an interesting site that if you have an opportunity should check out. http://www.victorianshipmodels.com/autoMG/index.html

The rest are pictures that I have taken a few years back. A couple of views of the barrel jacket. The jacket pattern would be the easiest of the patterns to make.

The side of the receiver

To give you the over all size for length

and height

A view of the feed block setting in the receiver

Here are some views of the feed block.

What a casting and machining project. The pattern alone had to be very interesting.

A few pictures of the lock.

Some more pictures of the inside of the receiver.

The look of this little gun is just beautiful.

The recoil spring

Now for the pistol grip.

If I had the time this would be a gun I would love to make, even if it were only in semi auto. The patterns alone would be works of art as well as the castings.

Building a small Volkspistolen

Chuck — Wed, 30 Dec 2015 08:00:57 +0000

Our friend Axel was here a while back and in one of our many conversations I mention that what was needed was a small 32 acp pistol that could be built with a minimum of tools, something like a WW2 German volkspistolen. Also being a fan of Impro guns, https://homemadeguns.wordpress.com/, I knew that it was a doable task. So leaving with nothing more then a magazine Axel was tasked with designing and making a non-firing prototype pistol with nothing more then the tools he had on hand. Those tools being a cheap table top drill press, a disk grinder, a dremel tool, a cheap tig and mig welder, a vise and a variety on hand tools. I want everyone to understand that this project was done as a non-firing prototype pistol only thus keeping with in the laws of his country.

This is what the final product ended up looking like.

This is his story. He wanted to come up with a Volkspistolen that was simpler then existing ones and adaptable to a variety of calibers.

Starting with a piece of steel pipe he cut the basic opening in the slide with a disk grinder.

His milling operation was completed using a drill press. With this set up he finished cutting the opening of the slide to the proper size.

This set up was also used to open up the ejection port. Hand fitting is the word of the day when making a pistol like this.

This is his press set up to form the bends necessary for the rear barrel support.

Using a drill of the correct size he was able to press the upper portion of the rear barrel support

Then using his tig and mig welder he welded to the lower block which would later become the completed lower barrel support and feed ramp.

After a number of hours of filing and clean up work.

The piece of material shaped to be a dummy barrel support.

The complete rear support after a great deal of filing and fit up.

A basic concept of the pistol design.

The making of the bolt for the slide. Again a piece of steel was fitted to the slide to start the making of the bolt. The bottom of the bolt was flatten with a die grinder and the grove cut into the bottom was done with a dremel tool.

After all the work is completed this is what you have.

Next the bolt face is made.

And welded on.

You can see how well the cartridge sets into the bolt face.

More hand fitting and it is set into the slide.

Test it against the barrel and rear support for proper fit up.

The next step was to weld the rear of the slide on. This fixture insured proper alignment prior to welding.

With the bolt welded it was time to hand fit the extractor.

A picture of the extractor and spring.

Part 2 dealing with the frame and parts of the fire control mechanism will be tomorrow.

FN-FAL in 7.92×33

Chuck — Mon, 03 Aug 2015 08:00:07 +0000

In my list of want to do build projects building an original FAL is on the top. The very first FAL ever built was in 7.92×33 and was slightly different then the current FAL that we know today.

This rifle is missing and all that is left of it are the pictures you see here.

These picture are from the FAL book published by Collector Grade Publications. If you are into the FN FAL rifle this set of books is a must have.

This is Pete’s , a friend of Gun Lab, version of a 7.92×33 rifle. His solution was to put in a new ejector block of his design with a spring loaded ejector. Then remove 0.900″ from the magazine to fit the 7.92×33 round.

A side view of Pete’s rifle. Notice the larger then normal ejector block.

The magazine actually looks like the original.

You can see in this picture the fit on the magazine to the receiver.

You can see here how the cartridges set in the magazine.

This his new follower

A top view of the spring loaded ejector

This photo gives you a good view of the magazine well.

A nice side view of the larger ejector block.

He converted the rifle to take a smaller hand guard .

AR-180B trunnion design

Chuck — Thu, 30 Jul 2015 13:54:25 +0000

An interesting question was brought up by Rick at http://ar180s.com/ a while back about making new AR-180B upper receivers. The actual receiver is not much of a problem however the trunnion is. The expense of making a new trunnion would be cost prohibitive so a different solution had to be found. In this case the thought would be to do what was done, or thought to be done by Armalite and that is using an AR-15 barrel extension pressed into a new trunnion block. So looking at a AR-180B we can see what the trunnion looks like in a receiver.

Looking at the above pictures you can see the difference between a AR-180B and the AR-180 below.

The above picture shows a flush front end with the threads. While of the 180B it is recessed.

There are a number of differences. The original is forged and then machined. You can see how the boss sticks out in front of the bolt locking area. While the 180B the rear of the trunnion is flush.

The reasons for these differences is because a AR-180b does use a AR-15 barrel extension pressed in. However there are changes to the barrel extension.

In this hidden view you can see that a AR-15 barrel extension would be to large for a trunnion as originally designed for an AR-180

This is a solid view of the same model. The barrel extension would get in the way of the recoil rods.

Even reducing the diameter of the barrel extension would not be enough to correct the problem. The extension has a diameter much larger then the inside diameter of the trunnion.

This can only work if the trunnion is also re-design. This is what Armalite did for the AR-180B.

Instead of a rounded bottom they squared it off to allow more material to support the turned down barrel extension.

As you can see in this cut away the reduced size of the outer ring of the barrel extension.

In this picture you can see the hole for the guide pin on an AR-15 barrel extension.

Reverse Engineering and machining the MP-44 trunnion

Chuck — Sat, 11 Jul 2015 15:43:05 +0000

Here at Gun Lab we do a fair amount of reverse engineering, most of what we like to make have no drawings. However when there are drawings or solid models available we will use them. With this said I have found that most of what is available on the internet or in books is just not correct.

A case in point is the MP-44 trunnion. I have all the drawings that I have been able to find on this part, a number of different sets are out there, and when compared with the actual part have found them to be lacking. Some are just wrong and in some cases I don’t think the person has actually looked at a part.

Over at weapons man he had a write up about reverse engineering a while back.

http://weaponsman.com/?p=21915

It was a very interesting write up and I recommend reading it.

Now back to the MP-44 trunnion. We were contracted a while back with making a limited number of new trunnions for the MP-44. He sent us a very good original one and we had a poor copy of one at the shop. Using these two pieces we started the project of reverse engineering it. The easiest thing to do was look for engineer drawings off the web. These are the ones that I found.

The measurements have been removed from these copies, however you can find them on the internet. I did use the basic drawing as a starting point. The sheets were cleaned and measurements were taken using a cmm, micrometers and pin gauges. Tolerances were set using not only the trunnion but also matching parts. When there was a doubt other parts were located to increase the measurement standards. This allowed us to come up with a reasonable solid model that we felt was accurate enough to start programing.

Even with this solid model and prior to making the parts we still caught a few errors that have been corrected.

Now comes the portion of the project were we start working on the machining of the part. A master cam programed was written to run the trunnion on the cnc machining center. It was determined that 7 set ups would have to be done to machine this part. This is a video of the master cam operation to complete operations 1 through 4.

With the program checked out we then ordered the proper tooling and set up all the off sets on the machine. Test material was brought in cut and machined to size to do a test run. This is the progress so far.The material was saw cut to size.

Then machined to the proper size and squared.

The first 4 ops have been completed. Op 1 and 2 cut the groves on both sides and drilled the ejector holes.

The next phase was op 3 and 4.

The parts are set up in the vises ready to machineThe barrel hole drilled and machined.

The hole for the bolt carrier is drilled, machined and then bored to a very nice finish.

The gas tube support is machined in.

The first six test pieces.

Even now we are still not working on the actual parts. These are 6 test pieces that will be completed and set to the buyer to test on his kits to verify proper fit. In this case because of tolerances we went with a smaller bore diameter for the barrel fit, it is easier to remove metal then to add it.

Solid model on the AR-16 rifle

Chuck — Fri, 13 Mar 2015 08:00:15 +0000

In my off time, work has been completed on the AR-16 upper receiver right side. In case you don’t remember this rifle it is a 308 predecessor of the AR-180. Only 4 were made and of those only 2 are known to exist. I had the opportunity to photograph one a while back at the Reed Knight collection.

Here is a close up of the receiver left side.

The right side.

A close up of the right side

Mr Knight was nice enough to let me look at and photograph them, however I doubt he will let me have one. As I really want one of these in my collection I have taken it upon my self to reverse engineer it to make me one. This is what I worked on this weekend between everything else.

More to come

Archive Photo’s 3-12

Chuck — Thu, 12 Mar 2015 08:00:34 +0000

I shot these pictures while at Woolwick at the Rotunda. It was an absolutely great museum. It has since been closed down and replaced with a typical diorama walk through everything behind glass museum. In its day it was a place where you could study some small arms, but mostly artillery up close. I spent numerous vacations there.

This is a weapon design by an unknown Africaan during the Boer war to keep the heads of the British soldiers down while they escaped. It is a clock weapon. The feed device seems to be missing but what you would do with this weapons is to set it for how fast you wanted the weapon to fire. One round a minute or one round every 5 minutes or more.

A side view showing the complete size of the weapon

In this picture you can see the cartridge being picked up to be fed into the barrel

I am not sure this was ever used or just a prototype that was made and not completed. It is however an interesting design and concept.