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.



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



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 dimensionsĀ  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.


DSC_6071wsThe finish on the upper radius is perfect.


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.




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

10 comments to Continuing the MP-44 trunnion

  • When you talk of the incorrect drawings floating around on the internet are you talking of the supposed original German prints floating around? I took them and built the complete MP44 in Solidworks and every thing seemed to match up. Now there is another set out there that was done by a guy supposedly from the German set but I have found numerous errors in his prints and you can see many mate up problems.
    Given that you are making trunnions, might we assume that someone is trying to introduce a domestic made version of the MP44? The stamping of the receiver components looks like it will be a real bear.

    • Chuck

      Hello Mongo.
      I have looked at a number of drawings of the MP-44 and they all have problems. They look correct when compared to the rest of the drawings but when compared to original parts they will not match up.
      I can’t say about a domestic MP-44. Currently I am only contracted to make correct trunnions. However, Ian at forgotten weapons just interviewed someone that is going to make a look a like, sort of, of the MP-44. There was some talk of reverse engineering a few other components as well. We will see.

    • Chuck

      If you have a correct set of drawings I would love to have a copy as it would make my life easier.

  • Rufus Chucklebutty

    What grade steel, and heat treatment is used on these ?

    • Chuck

      The original trunnions are very soft steel, they can be cut with a file. The first 6,which are the test pieces,are made out of 1018, the actual run of trunnions will be made of hardened 4140.

  • I added my Solidworks file of the trunnion to the drop box folder for you. I think I did that one in SW2011 and I do nto think I have saved it since I upgraded to 2015 version.

  • Pete F.

    Looking better and better Chuck!

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