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VG1-5 Preorder Now Available!

We are now taking reservations for out reproduction VG1-5 rifles! Price is $4000, and they will be ready to ship once ATF gives final approval on the design. The get on the priority list, contact Matt or Greg at Allegheny Arsenal – (814) 362-2642. No payment will be taken until the guns are ready to ship.

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AR-180B trunnion design

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.

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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.

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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.

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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.

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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.

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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.

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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.

Parts cleaning

This last weekend was a busy one, like most weekends here. On the list of projects that had to be completed was get the parts ready for heat treating. This meant bead blasting all the parts going to  heat treat. Not a weekend of fun and frolic. Thousands of parts needed to be cleaned and prepped. The though of cleaning them one at a time did not make for a project that I wanted to do. I have been looking at rotating parts bins for my bead blaster but have not had much luck. I knew a simple solution had to be out there, This is a video I saw on the net that I felt would be a long term solution, but for now something quick and simple.

So I made a manually operated rotating tumbler for the bead blaster. Here is a quick video of it and using it.

The first attempt was a 3lb plastic coffee can and just rolling it around.

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I needed something that was a little easier to use and could hold a few more parts. So I made one out of a 1 gallon bucket and some old castors.

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This is what the rusty bolts looked like starting.

SAM_0180And at the end after a couple of minutes.

DSC_6103sNot a perfect solution, but a workable one. When I have some spare time I will make a motorized one with a spray nozzle that does not have to be held.

MP-44 trunnions finish op 6

We have finished operation 6 on the MP-44 trunnions. The reason that we started with 6 samples was to insure that we would have correct samples when we finished. Two of the trunnions ended up out of spec after we finished this operation. The drawings and cam programing were changed to correct and problems. These are the pictures of the remaining 4 on there was to op. 7.

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IMG_0226sThere is still deburing that needs to be done then to the last op on the machining center.

Continuing the MP-44 trunnion

We have just completed the first operation 6 on the trunnion. It has also pointed out a few minor differences. When we started this project all we had was an original trunnion in very bad condition and a collection of out of spec drawings with incorrect dimensions.

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Later a trunnion in very good condition showed up from a friend to help move this project along.

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So as we have gone through each step of the process of reverse engineering a MP-44 trunnion and making a series of them we correct our solid model and it’s dimensions  have rewritten and the machining program changed as well. This is the trunnion as completed on the first sample of op.6. There is a great deal that is correct with this sample, however there are more changes to be made.

The top radius for the gas tube needs to be looked at.

DSC_6056csAll the machined dimensions are correct.

DSC_6061csThe angle and radius for the magazine to fit in is spot on

DSC_6064csJust check out the finish. These will be perfect when they go out.

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DSC_6071wsThe finish on the upper radius is perfect.

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DSC_6074csSo now on to the changes that have to be made. The first is that we have to machine down the side a little more.

DSC_6076wsA greater radius needs to be added.

DSC_6078wsWe took of a little to much.

DSC_6079wsWe mark each trunnion this allows us to keep track of each change as we make it from trunnion to trunnion. This is the first trunnion that we made.

DSC_6081cwsThis is the second trunnion. The magic marker notes the size of the chamfer.

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DSC_6088cwsOne more sample to finish to correct the last of the small items.

Another update to the cnc router

Here are a couple of pictures of the router setting on the new table. There are corner supports on every corner top and bottom. The next phase is re-wiring the controllers.

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DSC_6038sClose up of the support blocks. There are six of then to support the router off of the frame and wood cover. The holes on the end of the block is to allow us to bolt the router to it.

DSC_6040sAnother view of the support block set up.

DSC_6036sAll the wiring will be changer and run in cable supports.

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MP-44 Trunnions up date

We have now finished the first six test pieces up to the 5th operation. This next week we will complete op’s 6 and 7 and send them for verification for proper fit.

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DSC_6018csWith the first 5 operations completed we will be starting on op6 soon. This is a master cam simulation of the process.

Up Date to the CNC router

I finally finished the new base for the cnc router. There is no movement on this platform at all. Next will be the new controller circuits and cabinet.

DSC_6020sAnother view. The extension pieces are for the top cabinet and dust collector system.

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DSC_6019sThis shows the plastic inclosure for the computer and controller.

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In the white AR-180B upper receiver

A friend of mine sent me a AR-180B upper receiver to look at and study. Here are a series of pictures giving you a more detailed look at it.

This is a right side view. As you can see they were made with out a dust collector flap.

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A shot of the under side showing the welded seam.

DSC_5997csClose up of the rear sight stamping.

DSC_5978sA close up of the tig welded area for the front trunnion.

DSC_5977sThis is a series of pictures showing the front of the trunnion

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DSC_5982csA couple of shots of the bottom of the trunion

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