Post by killbucket on Apr 19, 2007 4:43:08 GMT -5
The MP40, like most othe AEG's feeds its ammo into the hopup from the bottom. When I went to use this gun's internals in my Browning replica, I needed to find a way to avoid having an ammo tube going into the bottom of the receiver, or worse, a magazine. It would be ideal if the hopup fed ammo rounds straight in from the top. Then the ammo tube could come in from a real ammo can, under a belt of bullets.
To use this hopchamber inside the Browning or other top- or side- feeding gun (sten?), I came up with a simple modification:
First remove all hardware involving the original hopup (put this in a labeled baggie, this mod is reversible).
Open up the hopchamber using this proven information by Taffy:
www.diggah.net/docs/Taffys_MP40_Hop_Fix.pdf
Except stop the cut about 1/2 way thru. The hopchamber will separate without cutting the end lug free completely, and this will make everything much easier to re-assemble and service in the future.
What you want to do is duplicate the index groove that is on the barrel holder, 180 degrees to the other side. This can be done with a Dremel or small file, even a hacksaw blade. Be careful not to cut the barrel keeper in half, you will have to run the groove right across it. The AGM hopchamber has a natural mold separation line here, so the line is easy to locate/folow.
Once this is done, the parts can be re-assembled 180 degres out. Now the chamber can be mounted upside-down, but the hopup itself is properly oriented!
Now we need an adjustment of some type.
It just so happens that the AGM hopchamber fits perfectly inside a piece of 1/2" i.d. PVC irrigation pipe.
So we cut a 1/2" long section, and cut a .400" wide notch out of one side, as seen below. A 6-32 hole is drilled/tapped opposite. a matching screw, .75" long, is end-polished and threaded into the hole. A nylon screw is preferred, I just didn't have one for photos.
Then it's a simple matter to file a notch in the hopchamber for this screw to poke thru and work the hop rubber. This assembled collar is glued into place on my unit, but friction is enough to hold it in place. The photos below pretty much illustrate the rest:
To use this hopchamber inside the Browning or other top- or side- feeding gun (sten?), I came up with a simple modification:
First remove all hardware involving the original hopup (put this in a labeled baggie, this mod is reversible).
Open up the hopchamber using this proven information by Taffy:
www.diggah.net/docs/Taffys_MP40_Hop_Fix.pdf
Except stop the cut about 1/2 way thru. The hopchamber will separate without cutting the end lug free completely, and this will make everything much easier to re-assemble and service in the future.
What you want to do is duplicate the index groove that is on the barrel holder, 180 degrees to the other side. This can be done with a Dremel or small file, even a hacksaw blade. Be careful not to cut the barrel keeper in half, you will have to run the groove right across it. The AGM hopchamber has a natural mold separation line here, so the line is easy to locate/folow.
Once this is done, the parts can be re-assembled 180 degres out. Now the chamber can be mounted upside-down, but the hopup itself is properly oriented!
Now we need an adjustment of some type.
It just so happens that the AGM hopchamber fits perfectly inside a piece of 1/2" i.d. PVC irrigation pipe.
So we cut a 1/2" long section, and cut a .400" wide notch out of one side, as seen below. A 6-32 hole is drilled/tapped opposite. a matching screw, .75" long, is end-polished and threaded into the hole. A nylon screw is preferred, I just didn't have one for photos.
Then it's a simple matter to file a notch in the hopchamber for this screw to poke thru and work the hop rubber. This assembled collar is glued into place on my unit, but friction is enough to hold it in place. The photos below pretty much illustrate the rest:
