GunLab (KnownHost) » MP-44

Machine gun shoot 11-30

Chuck — Fri, 02 Dec 2016 08:00:38 +0000

With the SAR show coming up we have a group of people staying at the house. So the Wednesday prior to the show a couple of us put on a small machine gun shoot, just to have some fun. Some of these shoots have ended up being a couple of hundred people in attendance. This year we wanted to keep it a little smaller so only about 50 people were invited.

Everyone at the house was allowed to choose one weapon from the reference collection to take out. In the past it has actually required two vehicles to haul out all the guns people wanted to take. This year it was kept small due to the amount of work that had to be accomplished along with everything else.

The weapons that were taken was the SIG AMT, the early roller lock family of weapons ( Gerat 05, 06 and the STG 45) A Beretta AR-70, the MP-44 as well as a variety of handguns. There was a number of machine guns at the shoot as well.

Here is a quick video of the fun that was had.

Building the semi auto MP-44 part 5

Chuck — Thu, 09 Jun 2016 08:00:34 +0000

This is another update on Pete’s project of making a semi auto MP-44.

In this post Pete goes over making the replacement pieces for the lower receiver area.

As with everything in the making of this rifle there is a great deal of trial and error.

It is interesting to see the tooling that Pete make to do the work necessary to complete the task.

There is a great deal of hand fitting and filing in this project.

It is looking better and better.

Pete is a master metal smith. I am impressed with the quality of the work that he has done on this project.

PTR44 locking shoulder damage

Chuck — Thu, 05 May 2016 08:00:26 +0000

Pete, a friend of gun lab, Sent me some pictures of a rifle that has come into his shop for repair. When he tool it apart and check out all the components he notice the condition of the locking shoulder. In the following pictures you can see the damage that has occurred to the PTR-44 locking shoulder.

It is hard to determine if the position of the bolt was not properly lock it up. It looks to be to high. This could have been a problem with the parts as they were made, out of speck, or it could be a problem that has occurred over time and usage.

Pete ran a file over the locking shoulder and it did not scratch it, a sign that it is hard. It could be improper material and or heat treat of the material.

Just be warned and check out your own weapons to verify the condition.

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.

The next step on the MP-44 trunion

Chuck — Fri, 22 Apr 2016 08:00:13 +0000

Not that we have finished running the parts on the machining centers it is time to do the final fit up. Using the 1018 trunions that we made a hole was drilled in it to allow alignment with the button pressed into the receiver. Then the blocks were tested to see if the fit up was correct.

This is how the trunion looks away from the receiver.

As it sets into the receiver

An angle view at the rear of the trunion for proper fit up there.

A look at the front

Another at a slight angle.

Some de-buring still needs to take place and we still have a few cuts to do on the manual mill. If you are interested in any new MP-44 trunions please drop me a note and I will get the request to Pete.

MP-44 Trunion op7 , 8 and 9

Chuck — Thu, 21 Apr 2016 08:00:46 +0000

With these last three operations we will have completed the work on the cnc machining center.

You can see the process of rough machining the bottom of the curve for the trunion. This op also machined the complete magazine well out.

A good side view of the rough machining of the curve.

All the trunions finished with this operation.

The basic set up to complete this op.

This is op 8. All we are doing in this step is to finish cut the curve under the trunion.

OP 9 then goes in and cuts the top of the trunion.

These two pictures shows the top roughed out just prior to the finish pass.

This is how they look after the finish pass.

All the trunions after the finish of op 9

A close up of the trunions.

The next step in the manual mill

Update on the MP-44 trunions op6

Chuck — Wed, 20 Apr 2016 08:00:44 +0000

It has been a while for a MP-44 trunion update. The next couple of posts will get us back up to date with the trunion project.

The new op 5 was to cut a slot and rough magazine opening to allow coolant flow and chip removal and still allow us to high speed machine.

Well it did not work as well as we had hoped. The chip load was so great as it was not removed as fast as it needed to be so we still had problems with the end mill chipping. So back to the drawing board. The answer was to put the trunion on the manual mill and drill the hole much larger but still under size.

With the trunion on the lower left we did just that. What a difference that made. So now with all the trunions drilled with a larger hole we were back on track.

We were able to then finish machine the inside hole to meet specs. with a great finish as well.

A close up of the finish of the inside bore.

The new process worked great. No chattering or broken end mills.

Building a semi auto MP-44 part 3

Chuck — Mon, 28 Mar 2016 08:00:31 +0000

In this post we are going to look at how the badly cut up and rusted lower portion of the MP-44 receiver was repaired. You can see in the first photo the condition of the under side of the lower front portion of the receiver.

The first set was to cut out the bad section.

Now it is time to fabricate a completely new section. A section of sheet metal is first cut to approximately the correct size. Then the first bend starts the process.

A second bend is made around a filler piece to allow for the correct thickness

Now back into the vise to bend both sides.

The correct thickness

The cure is installed.

This is starting to look good.

You can see that a great deal of hand fitting is required.

Very nice work by Pete. I am looking forward to the next installment. Pete still has a few rear sections if anyone needs one.

Machining the MP-44 trunions op 5

Chuck — Fri, 25 Mar 2016 08:00:29 +0000

With this post I am going over a few of the problems that have occurred during the machining of op5 on the 4140 hardened trunions. We ran into a snag while doing this op. A problem that did not occur on the 1018 steel parts.

A quick video discussing the problem and solution.

The problem is that we just broke our second 4″ solid carbide end mill.

This one being brand new.. Something need to change in the process that we were using to make the 4140 trunions. The problem as far as we can determine is chip load up that did not happen while cutting the 1018 blocks. Now the new procedure is to cut a slot down the top of the trunion.

This slot and the next op will allow for more coolant flow into the part and better chip removal away from the cutter.

This is the set up for the this op.

Basic and very functional.

This new procedure was just started and we are well on the way to being back on schedule.

This new method as reduces the chatter that we had to deal with.

Building an MP-44 semi part 2

Chuck — Mon, 21 Mar 2016 08:00:35 +0000

This is the second in a series of post of Pete, a friend of gun lab, building his semi-auto MP-44. From our previous post you could see the absolutely dismal condition of the cut up receiver pieces that Pete had to work with.

You can see from these pictures that there was no back section. So the only answer for Pete was to design the tooling and make a new rear section. This is that post.

In this photo you can see the style of the female die with the cuts for the ribs to be pressed in.

As with all stamping work to obtain the best possible product you must have a flat that is the same and you must have a method of properly locating that flat.

This male stamping die is much more complicated to make then most people think. All this tooling was made on a manual vertical mill.

With any press tool you have to have guide and alignment pins to obtain a quality product.

Pete does all his pressing on a simple shop press.

To fabricate the rear pieces it take multiply set up’s.

Some real nice tooling to make his rear section.

This is not a simple process to make the rear sections.

You can see for this final photo the quality of work that Pete produces.

If anyone is interested in a replacement section drop me a comment and I will forward it to Pete. He has a few of these left.