MP5/AR lower problems and potential improvements

Reno911

I recently purchased a printed MP5 trigger housing designed to use an AR-15 FCG so that I could run a HSS in my MP5 clone (PTRCT). The trigger housing is super impressive, built very well, and for about 700 rounds ran better than any AR platform I have with a HSS installed. Then what I think is the only design flaw showed itself: The wall between where the FCG is housed and the safety detent gave out. This wall is extremely thin, and after pushing the HSS back and forth from semi/super-safe/full safety many times the wall began to fail at the position where the detent meets the cam with the detent beginning to force its way through the wall. If a regular safety were being used I don't think this would ever be a problem because the same stresses would never be put on this thin wall. I am wondering if anyone else has experienced this issue. I've seen the you tubes with the printed MP5s, so I know there are enough of these rigs out there to lead to a consensus on the trigger housing design. Thank you for considering this and for any feedback.
cheers!!

hoffmantactical

Reno911 That area is generally always the same thickness, probably around 0.040". Interesting that the MP5 lower had an issue. Can you attach a photo of the failure?

Reno911

hoffmantactical Thank you so much for the reply!! I really should have taken a pic and am kicking myself now. Without thinking of taking a pic I decided to try and "fix" the housing by cutting out the failed area so I could try to insert a patch made of metal. Working on this now just for kicks.
The wall gave out where it is thinnest, 0.040" sounds right. The detent was pushing through the lip at the top of the channel the detent sits in. I was at the range and changed the HSS from super-safe to semi, but when I hit the fun switch I kept getting super-safe mode, so took a closer look. The detent kind of being at an angle at that point allowed the cam to just barely keep binding the trigger and firing in super safe mode.