I am an 07/02. I have a PTR MP-5 clone. I registered an SEF trigger pack as a machine gun. It is functioning in semi auto even when set to full. The sear trip lever is working when manipulated manually. Working the bolt without the stock attached it appears that the hammer is not cocking all the way to the auto sear.

Ideas?

Did you cut your SEF pack enough so that when installed in the grip everything goes forward as much as possible? I cut one wrong once and it took me a while to figure it out.

I believe so. There is plenty of room for the shelf to clear the notch and basically no room front to back in the housing to move it anyway.

Do you have a full auto carrier?

Yes. PTR guns ship with a full auto carrier and if I install the pack with the hammer cocked to the auto sear, the carrier hits the trip lever, but the standard sear is catching the hammer.

I sorted through a bunch of old HK Pro stuff and the only real advice I found was "just try different combinations of parts until something works".

That worked.

Now I have a machine gun. Ho ho ho...

I've got a transferable sear, and when I first got it, the grip-frame I had it in sat too low on the shelf for the sear to be tripped, not much maybe only a 1/16" but if the trigger pack doesn't sit high enough it won't function properly.

If you can push the grip-frame up once installed, its probably too low, you can try putting a shim on the shelf to see if that raises it.