I have given up.
My Erma will not feed.
Usually the bolt does not come back far enough to eject the round and i get a stovepipe.
When it does eject it may or may not pick up the next round.
But sometimes it will cycle four times in a row.

Cannot find friction. Have had it apart fifty times.

Previous owner has cut 3/4 inch off rear of barrel. I rechambered it and straighted out his grooves for barrel pins which he'd filed cockeyed.

I am afraid of this design for following reason:

There are two alignment pins, number 37 on Numrich drawing
EM1. Accessories | Numrich Gun Parts
Those pins align the upper receiver(36) to the trigger housing(1) below.
The pins i took out were 0.157 inch diameter. They were a loose fit.
I lost one so made a replacement 0.156 inch from 5/32 drill rod.
With that 0.156 pin(smaller by just a thousandth of an inch) in the rear position there was a thousandth or two vertical play , i could pull up on rear sight and feel the upper receiver move up relative to trigger housing.
Well when i did that the gun snapped and would have fired were a round chambered.
The sear, part 21 on that diagram, is fixed to the lower trigger housing.
The "firing pin piece"32 which rides on the sear and is held rearward by it, is held in vertical position by the upper receiver.
So relative vertical movement between upper receiver and lower trigger housing lets the firing pin move up and disengage from sear and come forward, just as if the sear had been dropped by trigger. On this gun that took 0.001 inch of movement. Safety would not prevent it.

As i got this gun it was 0.001 inch away from dangerous.
I made two 0.159 pins and they're a tight fit but will go into the holes. They eliminate that vertical play between upper receiver and trigger housing.
So now it's 0.003 inches away from dangerous.

I'm not gonna finish this one because 0.003 of an inch from tragedy is too close for me. More likely i'll weld the barrel shut and hang it on the wall. Or maybe see if i can whittle the stock and fit a 10/22 action in it.

I hope you have better luck with yours.

old jim