Weekend update and the fun of machining

Nothing really exciting to report. I spent the weekend machining large pieces of metal into smaller pieces. We have shipped the test MP-44 trunnions to Pete and while we are waiting for his report back we are filling our time working on making stamping dies. In this case all the pieces are sized and we have started machining the the individual pieces for the AR-180 upper receiver stamping dies. A quick look at the solid model of the stamping diesAR180 Complete Die3

AR180 Complete Die2

AR180 Complete Die1

This is what it looks like in the making phase. Here are a few pictures of the top and bottom plates being sized up on the Allan Bradley cnc mill. A great deal of the die steel is not heat treated and just basic run of the mill scrap steel. These sections came from torch cut trash steel from different job sites. You can see the type of edge it has and need to be cleaned up and sized.

DSC_6223sA close up of the edge. This will take a great deal of work to clean up and make useable.

DSC_6224sSo Saturday and Sunday I got to do this. A basic program was written to reduce and clean up the edges 0.030″ at a time until they were clean up.

DSC_6227sThe two bigger pieces were machined. The top and other edges will be cleaned up on the HAAS machining center.

DSC_6226sAll three of the pieces ready to continue on to the next phase.

DSC_6228sThe actual heat treated press areas are also machined to size and we have started on the forming portion of the dies.


Unique 22 single shot rifle

Our friend in Germany, Axel, knows that I am always interested in weapons of all styles and calibers so with today’s e-mail came some interesting pictures. I have a number of different types of single shot weapons and find them all interesting. Here is one that I have not seen before, not that that means much. It is a single shot with a lifting breach action.

Right side view of the rifle.

5556670.1393570507Left side view. Interesting shape for the receiver.

5556670.24458173Close up of the receiver.


5556670.226234334The action open. Lifting breach block and a very simple extractor.

5556670.527397275Interesting front sight.



FN-Fal 7.92×33 second version

With the last post we made on the 7.92×33 FN-FAL we showed a FAL that had a new ejector block and magazine made to allow the rifle to shoot 7.92×33. This post will show a different approach to reach the same conclusion, shooting 7.92×33.  This series of photographs comes from another friend  of Gun Lab and how he converted his rifle to use MP-44 magazines.


IMG_0604cThis version the owner cut down the receiver by 0.900 and welded support plates to enlarge the magazine housing.

IMG_0579acHe also put a side rail on it for a scope. You can also see the flapper magazine release for the MP-44 magazines.



A close up of the magazine release .IMG_0575c

IMG_0578cWhen the receiver was shorten then the bolt and bolt carrier also had to be shorten as well.




IMG_0581cReference pictures to show the length of the new bolt.






A view of the underside of the receiver to show the magazine well.


IMG_0572cA series of pictures showing the size of the new bolt carrier.





A great deal of work went into building this rifle.


The loss of an interesting web site

It appears that “DIY self defense”,( has gone off the air. It was a great site and he had cool stuff that he found and posted. It and Improv Guns ( were the only sites that dealt with home made firearms.

I have always found it interesting what people can come up with when weapons are outlawed by their government.

I will miss his site.

Parts wanted and for Sale!

Looking for G-43 fire control parts. Hammer,trigger,sear. This is for one of the projects we are working on.

Continue reading Parts wanted and for Sale!

FN-FAL in 7.92×33

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.


02011230_Page_1cThis rifle is missing and all that is left of it are the pictures you see here.




scan0040cThese 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.

GE DIGITAL CAMERAThe 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

GE DIGITAL CAMERAThis photo gives you a good view of the magazine well.

GE DIGITAL CAMERAA nice side view of the larger ejector block.

GE DIGITAL CAMERAHe converted the rifle to take a smaller hand guard .



A visit from AR-180s

Rick from dropped by yesterday and spent a few hours at Gun Lab. It was a nice visit.  We both got to show off projects that we have been working on. I was able to get an up close look at his shorty project and his machined out of tubing AR-180 upper. Nice work. The shorty projects looks like a fun build. Now to go back to the salt mine of my shop for today. Looking forward to your next visit.

AR-180B trunnion design

An interesting question was brought up by Rick at  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.


DSC_6119csLooking at the above pictures you can see the difference between a AR-180B and the AR-180  below.

DSC_6125csThe 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

AR-180B barrel extension shadowThis is a solid view of the same model. The barrel extension would get in the way of the recoil rods.

AR-180B barrel extension 3Even 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.

AR-180B barrel extension 2

AR-180B barrel extension 1

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

AR-180B barrel extension 180B proper 1Instead of a rounded bottom they squared it off to allow more material to support the turned down barrel extension.

AR-180B barrel extension 180b proper 2

AR-180B barrel extension cut away

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.


OP 7 completed on the MP-44 trunnions

Op 7 has been completed. This is a major mill stone on making the MP-44 trunnions. The rest of the machining will be done on the manual mill. It will be easier on the manual mill then making the number of fixtures and tooling that would be required on the cnc machining center.

This is op 7. You can see the original next to one of ours. The manual phase will add the chamfer  to the groves.

DSC_6115sYou can see that the trunnions are dimensional correct

DSC_6116sA close up of the trunnions.

DSC_6114sA picture of all 6 trunnions completed and de-burred.


More on the MP-44 trunnion

Operation 6 has been completed on the MP-44 trunnions. A couple of problems were noted. The first is the difference in length on the front of the trunnions and the second was the fit up of the locking shoulder.

This photo shows the difference in the lengths

DSC_6105wsYou can see the corrected locking shoulder fit up

DSC_6107wwsThis photo shows where the end mill breaks during op 6 not cutting the slot for the locking shoulder.

DSC_6109wsClose up of the un-machined area

DSC_6111wsAs with every part made there is always a problem lurking in the back ground. We thought that we had complete op 6 on all the trunnions only to find that on the last part the end mill had broke. This caused a cascading failure problem. The next end mill, which was a custom slot cutting tool, also broke. The program was rewritten again to correct the problem and all six parts were finished through op 6.