Hello everybody!

first, sorry for my english...

I plan to buy a MP40 here in Belgium (about 500-700$ here), but our Law permit to possess FA guns but not to shoot it, and , soon, ,  those FA only can be totally forbidden and have to be deactivated or destroyed(special thanks to our leftist gov't).

For prevent these sad ends, I'm searching for a method for building a semi auto conversion whit original open bolt function without exterior modification. This conversion must be presented to the National Proofbank in liège for official recognition and that can be the last chance for us to shoot this wonderful historic piece...

I know that there is few transformed MP40 (SLK 38/40 ?) and a completely rebuilt semiauto MP38 on the market in Germany,  but I don't have any idea of the system adopted...

I think about  adaptation of one of the the sten's mechanism (MKIV) can be a good way....

If you have any ideas, or if you have seen one of these systems...

Thank you in advance,

Jean from Liège.

If you can have an open bolt semi auto in Belgium then you are in good shape.  If you have access to the Yugoslavian M56 submachine gun lower grip and fire control parts, then you have all you need.  With a little minor work you should be able to transfer the fire control pieces into the MP40 trigger tray with the selector permanently welded in the semi-auto position. 

Kevin

I am not sure that the "short" bolt that is used in the MP-40 would come back far enough to trip the trip lever on a M-56 lower (to accomplish the semi-only). To use the M-56 lower you may need to weld an extension on to the rear of the bolt.

Another option would be to use the lower (or better yet, the lower & bolt) from a Star Z-45 parts kit. The Star lower uses a special tow position trigger/sear that when the trigger is pulled to the first position, it lowers the sear (releasing the bolt) and it pops right back up to catch the bolt on recoil. When pulled all the way back to the second position, it re-pulls the sear down and holds it. It would be very simple to modify the Star lower to prevent the trigger from going all the way back into the second position.

To use the Star bolt (which uses a floating firing pin that is activated when the bolt comes into contact with the trunion) you would only need to relocate the charging handle to the opposite side of the bolt. (and it is already drilled for that)

Of course, this is assuming that you can legally build in an "open" bolt configuration.

Hello Guys!

sorry for this late response but i was off for some weeks...

the bad news is that the prohibitionist law is passed in 2 weeks without any consultation due to à killer armed with a "legal owned 30-30"...

the good news is that I' have a plan!  I just draw-it on some pages and I plan to made a prototype on a demil MP specimen.

until now, I just have to replace the sear + the transfer bar and drill 4 extra holes for pins and springs...

the last challenge is to made a solution for disasembling the gun easely...

Jean from Liège.