Great Job, it came out very nice. You are correct in your assumptions regarding refinishing, it is not required.

Thanks. After each layer of "pigletting" (can't really call it hogging with that skinny bit and a router) I left just enough to make one final "RCH" cleanup pass around the template. I am not completely satisfied but hey, it was the first and the next will be better.
I've seen pictures of "finished" 80% lowers that make you wonder if they should have background checks for tools at Home Depot...
But I guess if it goes "click-bang" every time it's supposed to it doesn't matter what it looks like, right? Nah, not for me...

I was going to take pics before assembly but I got anxious and had to put all the bits and pieces in and tomorrow it breathes...

Went to the range Saturday. Put one round in a mag, went bang, locked back like it's supposed to. Put two rounds in the mag, did it's thing. Yeah Boi. Did some threes at 25yds to dial in the sights, moved out to 50yds (my old assed eyes aren't much good for any farther with open sights) tweaked the sights a bit more and dropped the next hundred or so within the six inch circles. Works for me!  No rest or bags, just elbows and sling. 130 rounds total. I should've done this years ago! I freakin' love this thing!

I GOTS HAPPY FEET!!!!!

Well done man! It's a whole nuther dimension to BRD!

 

Which jig did you use?

Modulus. And their lowers.

That is awesome news. Congrats on pulling the whole job off in such a successful manner.  

Question.  On 80% lowers with the rear pocket pre-machined, why would a vendor say it's
"just roughed out, it is not to the exact finished size nor is it exactly placed." ?

I can see the depth and fore/aft not being super critical as long as it's not too deep and is big enough
for the upper receiver lug to fit in.  But the plans I have say the width is .500 +/-.004, this is I assume
to assure a good fit of the upper receiver, and that it's centered on the buffer tube opening.  It seems to
me that having the upper centered on the buffer tube opening, and with as little side to side slop as possible,
would be a "Good Thing".  No?

The issue I'm trying to wrap my head around is I milled one of these, and the jig had me shave a few thou
off one side of that rear pocket but not the other.  Now, instead of the proper .502 or so I had pre-milling, I have .509
spacing from inside to inside where the rear upper receiver lug fits.
I don't think it's a terminal problem and I do think I can account for it next time, but I'm trying to understand
what went on to make this happen.  As far as I can tell, not being able to measure anything off the centerline
with my meager micrometers and calipers, either the jig was off, or that pocket was off.  And there is some slight
variation L/R in where one can place the jig, but it's very slight, thousandths.  All my other measurements
check out good against the plans, or what I consider good for a guy with a router anyway.  Trigger slot, FCG pocket
width, alignment, etc, etc.

Any thoughts?  I'm not unhappy with the jig or lower or think anything is "wrong" exactly given what we're doing here
by hand, but I want to understand it.  What brought this onto my radar as this is a pre-anodized lower and the milling
in that rear pocket only took the anno off one side, so I started looking and measuring.

That looks great! Don't worry about corrosion, I have several bare lowers that have been laying in my humid garage in FL for 8 years and still look good.

Now I wanna show off..  

Up until the latest generation of 80% lowers, the end user was responsible for machining the entire shelf themselves. The new design just give you a head start on that particular area. 95% of the material in the shelf area has already been removed for you.

I see that the forward part needs additional milling and that's cool, is part of that 5%  supposed to be the rear or sides?
Both of my receivers have measured out as finished side to side before cutting (.502or so).
Since there is a spec for the side to side distance of .500 +/- .004 I'm not sure how that dimension could be
un-finished unless it was left small to be finished out.  Mine was fine side to side before milling,
and now it's not(.509) as the jig had me take a couple thou off one side.  I'm sure it'll function fine but
it's creating some slop in the upper that needn't be.  

The only reason I "kissed" my rear shelf/pocket was that there was a dimple of a 3/8 drill hole on the front edge and I thought it looked like shit so I cleaned out the rear shelf with the template. You can see from the pic on page 2 that I was pretty much centered.

I drilled all the holes by hand and that was a bit of an ass whoopin'. I'll have a drill press for the next one. Or two...

Are there any 12 step programs for BRD? I think I might be one of those genetically predisposed to addiction...

Larger pic, please! (Doesn't have to be as big as mine. That was with my iPhone...)

Never mind. I got there. Looks nice!

Drill press helped a lot, but finding one that drill straight and has a true chuck without a bunch of money involved isn't easy.
Still gotta be better than a hand drill though.

So, my 2nd lower is about 1/32nd offset, the trigger opening and FCG pocket.
I noticed the former, then confirmed the observation on the latter.
The lower directly before it is off so little I can't see it, I can see 1/32nd if the
context is right.  The jig has no appreciable wear, and is a Modulus design that
centers on the front takedown and the rear buffer tube hole.  My conclusion, since the
jig basically cannot be off, is that the buffer tube was not drilled perfectly centered on the
forging.  I wonder how many off-center 80% lowers you see are because of this?
I even tried forcing what little play there is in the jig off toward the thick side and it
wasn't enough to line it up of course.  I'm sure it'll still go bang but it's annoying.

I think I might devise a way to mount the jig on a given lower and put a scribe mark
on the left and right side of where the FCG pocket will be and measure it ahead of time
to see how it will come out.  The jig sitting above the top of the lower make is difficult
to just use a ruler or such, might be able to make or buy something to chuck up in the
router since it's a stable straight platform.  The other thing on my wish list is a tighter fitting
buffer tube screw, there is a bit of play there I'd rather there not be.

Wonder if the billet lowers are more apt to be correct?  

On an up note, my .155 and .374 reamers made some perfect pin and safety holes.
Least as perfect as a $250 drill press with a $60 chuck and arbor will get anyway.
I started with the smallest of my cache of safety selectors, there seems to be considerable variation.

Fun stuff.

great job !!!
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