Record cold and snow in MN. I'll soon be locked in the shop for the
duration of winter and been casting about for a worthy project.
I came accross this:
Is this a good forging to start with? Anybody else done this? Any
heads up for problems? Any fixturing suggestions? I'll plan on
building quality fixtures to knock 'em out on the CNC mill.
Drawing and machining a prototype lower was one of the first major
projects I had in Solidworks. I've always wanted to go back and redraw
it because I know there are better ways to get-er-done now. We started
out with a solid block of material. iirc it was at least 12 ops to get
it all done. Well, almost all done.. had to leave a couple holes out
since the ATF wasn't here to serialize it.
Any special reason you left the bottom of the mag well parallel to the
top? Some current mags wouldn't fit.
ATF doesn't need to serialize it nor do you if you're building it for
your own use. You can't sell, give away or otherwise transfer it unless
you have a manufacturer's license, which is when the serial number
becomes necessary, which the manufacturer does, not the ATF.
That was the way the customer wanted it. I had to reverse engineer one
that he brought us. I was lucky enough to find a dxf of an AR-15 so I
could get the proper hole placements and tolerances.
Exactly, this was an actual job we were looking at getting so if we went
into production of the parts (iirc) an ATF agent (or someone that could
do it) would have needed to be present during the final operation and
Whoever inherits it needs to do the paperwork for an NFA firearm.
Remember this applies to NFA firearms, not to "ordinary" firearms.
The paperwork is confusing since it generically refers to "firearm" in
the title, however further into the forms they specifically refer to NFA
firearms only. Look at ATF form 1 which is titled "Application to Make
and Register a Firearm", but further down on the instruction page it
specifically refers to NFA firearms only. It also has "Estate
Procedures: For procedures regarding the transfer of firearms in an
estate resulting from the death of the registrant identified in item 3,
the executor should contact the NFA Branch, Bureau of the ATF...". You
can download the forms from the BATFE site.
Bzzt-WRONG ANSWER. It is NOT an NFA firearm unless it's full-auto or
shorter than legal length(26") or has a short barrel(<16" for a
rifle). Full-auto creation is prohibited as of 1986 for mere mortals,
you have to have the special ATF permit to do that or you go to jail,
do not pass go. No new full-autos for civilians. You CAN sell your
semi-auto creation, just don't make a habit of it. ATF regs are fuzzy
in this area, if they recover a number of home-made guns that can be
traced back to you, you WILL stand a good chance of seeing the inside
of the crossbar hotel. If it's sold, you should put a name and a
serial on the thing, ATF has the requirements for marking on their
website as far as depth and size of lettering. State and local laws
vary, but federally, it's legal to make your own pistol, rifle or
shotgun with no other paperwork. ATF doesn't even have to know about
As far as the OP's desire to make an AR lower, knock yourself out.
You'll find that the tooling cost will go a long ways towards a
completed gun, so it's not really cost effective. I've seen lowers as
cheap as $60, stripped. A tap for the buffer tube will run at least
$100. Then you get the fun of trying to chop out a close fit on the
mag well without a broach. The only thing you gain by doing it
yourself is the experience and an off-paper lower. What's your time
I know exactly what my time is worth. the only job I've collected a
salary for in the last 25 years is Township Supervisor. It pays $600 a
year and I put in 150 hours to collect it. So $4 an hour is about
I remember talking to another fella in my business. He said,"I don't
mind the minimum wage but i do wish I could earn that much"
Seriously, the goal here is to do something to be proud of this
winter. AND, do it in the heated shop.
Early on the thread discussed the legality of making your own AR lower.
There was a lot of confusion about restrictions with people confusing
NFA only restrictions as applying to non NFA firearms.
You also seem to be confused about NFA firearms, as the 1986 date you
refer to only applies to full-auto machine guns, and not to other NFA
firearms like short barreled rifles, silencers, etc.
I'm vaguely kicking around the idea of sending in the paperwork and $200
to get a tax stamp and paperwork to legally build a silencer, but I'm
not sure if I have enough ambition to do all the paperwork.
Karl, I wanted to ask a question about manufacturing methods for the
Look at this:
He had to reclamp his piece numerous times to make it on a CNC mill. I
wonder, how much of that is due to lack of the 4th axis.
My feeling on this is that with a suitable 4th axis, this receiver could be
done in 2-3 reclampings, or perhaps even one. With a 4th axis, clamp
once, and then turn various sides towards the spindle to be machined.
Am I making any sense?
I had not seen this site, thanks.
You have a valid point, but you lose so much rigidity that your
machining speeds would be killed.
Most parts are manufactured with a real eye on fixturing. That is ways
to quickly remount the part for the next operation. With a good
fixture design, you can go from one op to the next in a few seconds.
I had not seen this website, thanks for the link.
Well, yes, but when I am making a one off receiver, I do not care as
much about machining time, as about how much time would it take me to
make one off fixtures, reclamp everything, touch off the tools, align
So, if it would take me 5 hours of machining time to make a receiver,
but only one personal hour, it is a better deal than 30 minutes of
machining, but 3 hours of making custom fixtures and clamping and
reclamping and dealing with mistakes.
Anyway, I admire your plan and am looking forward to seeing how you
make that receiver. I am getting an itch to make something like that
Not speaking from any actual knowledge, of course.
Production fixtures would probably use hydraulic clamping, and be able
to flip the part around and reclamp in a matter of seconds and/or use
palletized fixtures holding a number of the parts at a time for quick
changes in the machine and off-line reclamping.
For the low volume us HSM types do, you can't beat 1/2" socket head
cap screws holding a part in a custom pocket. Use an impact wrench to
change parts in a few seconds. Often one screw will do. Two will hold
dang near anything. Another great device is a toggle clamp
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