More legal requirements and stuff

Since my Uzi build started with a machine gun parts kit, the fire control group has some naughty bits in it that are definitely not legal for use.  We'll need to modify the lower grip assembly so that it's both legal, and usable with the striker fired semi-auto bolt.  The first thing to do is to make sure that the selector lever can't slide far enough forward into the full auto position.  That's pretty easy to do, all you need to do is weld a blocking plate into the grip assembly to limit the selector lever's travel.  I made mine out of some 1/8" steel plate and welded it in.  You can see here the plate welded in so that the selector lever can't go any further forward.

Next up is the sear.  Aside from the FA sear being a naughty bit, it won't work with the striker setup anyway.  It's not shaped right to catch the striker.  There are semi-auto sears available, but I'm cheap and it's very easy to modify the original.  Using a cutoff wheel in my Dremel, I started cutting away at the sear.  The left ear is the only one that matters because it's the one that catches the striker, but I trimmed them both, for good measure.  Here it is with the first ear trimmed:

And with the second ear trimmed:

I eyeballed the angle based on pictures of the commercially available sears.  It's not ultra critical on these things, as long as it's close enough so that the striker can't slip past the sear.  You can see here on the right side of the pic how the modified sear catches on the striker:

I wanted to check my sear engagement on the striker, so I got out my handy Sharpie and colored the sear ears.  Then after assembling things and dry firing it several times, I pulled it back apart to check the wear pattern.  Here's how much actual contact I'm getting between the sear and striker(on the left ear).  Not a lot, but enough.  More contact will lead to trigger creep, and after everything is together and working, I'll see what I can do to improve trigger feel.