Colt 9mm SMG clone help

[judgecrater]

I believe mine originally had just a roll pin to keep the end cap from rotating.
At a later date I tapped the hole and installed a 12-24x1/2 cap screw to secure the end cap.

The end result is like this.

2122D69A-5C6C-4176-900A-2DF3FF99B993.jpeg

Thanks for the picture. That should hold it!