Originally Posted by
rukh013
I'm looking to put a UL frame from a proto pmr on a super thin custom rail
How far down from the top edge (where the body sits) to the RT sear pin?
Search the tech info. I think its in a sticky. You can find a cad drawing. It will have the dimensions I suspect.
Originally Posted by
rukh013
is the sear needed, can I just trip the on/off with a pneumatic piston?
Yes, the sear is needed. It holds the bolt from going forward due to the pressure in the front chamber. The on-off is used to close the air path to the front chamber before the bolt is released by the sear.
Originally Posted by
rukh013
What is the front of the sear for? not the "bolt hook", the nose
The front of the sear prevents the sear from rotating forward until the bolt has fully reset. The ensures the bolt is reset before the on-off can open. If the on-off were to open before the bolt was reset, the air flowing into the chamber would prevent the bolt from resetting and wouldn't allow the sear to catch the front of it.
Originally Posted by
rukh013
What would be the easiest way to make the concave rail top using a drill press?
Use a ball nose mill bit and a cross sliding vice or table. If your drill press does not have good side to side rigidity, then it won't work well. You won't have good tolerance. If it does have good rigidity, then it is the same as a mill.
Except for the Automag in front, its usually the man behind the equipment that counts.