Don't give up!  If anything buy another one.  That way you can build a "simple" one and one that is a lot more detail oriented.  And post pics if you could.  

On a side note, I wish I could buy the .dxf files for these.

I just meant on the inside. So the upper was pretty loose, side to side?

My idea of a buffer tube is to just weld a pipe on the back. And I'm not going to bother with the fence or the take down and pivot pin detents, just get those pins with ball detents in them.

The inside pocket of the lower, where the rear lug on the upper receiver sits, is much wider than a traditional lower. I did build that area up a bit on both sides.  I don't know if it was 100% necessary as the take down pin should hold it in place, but I did not like that I could shift mine side to side a bit if I really pushed on it.

I welded two spacer plates into mine so that the rear lug of the upper would be properly centered and retained.  You can see them in this pic.

i bought a ar10 kit after seeing this thread the first time.  still in the finishing stages.  it actually goes together pretty easy.  I'm using a pretty basic set up, flux core wire on a Lincoln 125.  still need to order an LPK and get a mag.  I want to make sure everything fits before I get too close to done.

It does seem that extra metal in those spots should be included as part of the kit.

"Some assembly / ingenuity required"

I bought one of these and decided to try a combination of JB Weld and Devcon epoxy to see how it would work.  While the trigger guard, rear tang, and rear side plates can be JB welded together and seem to have held up so far, I could not get the buffer tube assembly to stay in place and ended up having it spot welded. I also ended up having the front magazine plate tig welded.  I was test firing the receiver, when the JB Weld/Devcon epoxy gave out and the front half of the receiver fell off.  I then had it welded back together.  Yesterday, while running another test firing, the front pivot pin pieces gave way. When I disassembled the rifle they had come loose. They are now at the local weld shop getting tacked into place.  Based on these results, JB Weld and Devcon Expoxy will not hold up to the stresses imposed by firing.

As additional information, I went to 308 pivot pins so their greater lengths would support the upper better.  To hold the rear pivot pin in place, I drilled out the existing hole for the rear detent pin with a 5/32 drill and used a roll pin as a sleeve for the rear detent spring and detent.  I filled the rear part of the lower with Devcon Epoxy and used the expoxy as the base for the buffer tube detent pin and spring. I also filled the area around the safety with Devcon and used another roll pin to help secure the safety selector spring and detent.

I did mill out the side plates for the magazine release, and am using a extended magazine button, so there isn't any problems there.  I originally JB welded the piece for the front detent pin into place but the welding heated the metal and it caused the piece to fall off. I used a different kind of putty to hold it back in, and despite two hours of heating the front of the receiver to try and braze the pieces into place (I failed miserably), the putty is holding.

This has been a frustrating and enjoyable project.  I will get pictures when I get it back from the weld shop and post them

You got farther along w/ the glue than I did.  Congrats!.

Still waiting for Super Glue V2.0   I got faith in ya.  

As for me, while I'm still trying to make the most of Ohio's limited summer weather, I think I may hold out a little longer still, may have a TIG welder on the way.  Sure would be a sweet first project for it.  Will pro able still do another with the MIG just to see the difference.

I just got a coworker to purchase a kit tonight.  Hopefully he will want to get us a few pictures of his build.

In my pic above you might notice that I also welded in another plate to thicken the receiver wall where the selector detent hole is drilled.  It was just too thin in this area.

Yeah, I did notice that. Kind of interesting how both ended up making nearly the same shaped insert there.  When I help build my coworkers kit,  I plan on making that adjustment right away. I feel that it could have easily been designed that way from the beginning.

Great thread.

I could be mistaken but doesn't getting the local welding shop involved bring up some possible legal issues?

Yup.

I am not sure,  all I did was walk into the shop and ask if they would weld here and here while I helped.  I am waiting until the local welder gets off the Elk hunt so I can take the receiver in and have the pins welded back in place while I help (I  am trying to learn brazing and welding as a part of this project).  In my case, I had previously completed the work on the receiver with JB weld or Epoxy, and during test firing the vairous pieces had failed and hence the trip to the weld shop to repair what had failed during test firing.

Yeah, I don't think they can charge you for fixing it.  Fortunately you'd already built it with JB Weld, so it's a firearm already, and they're helping you repair it.  But they can't charge you for the repair, or they'd be a gunsmith w/ an FFL.

That is what I thought, the guy teaching me the welding has been a friend of mine for years, and he is teaching me welding and brazing, while I teach him how to put together an AR from a stripped lower. Money has not exchanged hands, nor is it likely to.  I have spent more on jb weld, devcon expoxy, and brazing materials than  I spent for the kit.  I have decided that this will be my one and only steel receiver.  I can buy a 0% aluminum lower for $25 from several places and turn out a completed receiver far easier than I could put this kit together and make it work properly. (I have built up six 0% receivers with my mini mill).  Before test firing the lower, I used my etch o matic to mark  the reciever,  with manufacturing data, model number and serial number so it was a completed receiver.  I live by the philosophy that you never create problems that invite the man into your life  (even though I am a retired LEO myself).

Good plan, but it also serves to let other folks reading this thread know you can't just swing by your local welding shop & have them weld your kit together for you.

You are aware that, at least under federal law, that is immaterial as to whether a receiver is considered "completed" or not?

I am aware of that presence or absence of markings doesn't have anything to do with whether or not a receiver is "complete".

The point being made in the posts above, is that I "completed" the receiver, then during test firing of the "completed receiver", it developed cracks and was and is  in the process of being "repaired".

The main idea behind the discussion in the posts above, is to remind the members that you can't  buy one of these kits and take it to a local weld shop and have them put it together for you. This is no different than someone buying a 80% lower and taking it to a local machine shop and having them mill it out for you.  The work has to be done by the individual who purchased the item, otherwise the business completing the work is "manufacturing" a firearm and needs the appropriate licenses, and has to transfer the completed receiver to you via a 4473.

Thanks for clarifying.  The statement I quoted could be interpreted, by a novice, to imply that the markings somehow "completed" the receiver.

On the topic at hand, I don't think the regulations necessarily require *all* operations be done by the owner - just the ones that will take it from 80% (still a lump of metal) to 81% and higher (firearm).  In that light, could a person take the plates to a machine shop or welder and have some early but critical operations performed?  I'm thinking specifically of the the threaded boss for the receiver extension.

Similarly, could the owner "dry fit" the plates together without any attaching, mark where machining operations need to occur, and then sent those individual plates to be machined?

Note these are all hypotheticals.  For my own part my interest is in mating the steel AR parts with the PPSh-41 magwell (also on their site) so I can use drums with a 7.62x25 upper I have.

It has been interesting to me to see the expanding interest in completing your own receiver, whether steel, aluminum, or plastic.  I would not be surprised to see some eventual regulations come out regarding the completion of your "own receiver", but  I think at this point in time they are more concerned with someone attempting a mass production of the items they are selling as "receiver kits"  (ie: the polymer lower raids), than the individual.  They will wait for some kind of use of a homemade receiver in some kind of crime before they go after them.

On my part, this was a project to see how well two part epoxies would do in putting together a receiver that would stay together, they do not work for that purpose, (so much for the fabled JB Weld lower).

I have considered buying another kit, and attempting to use a product called steelalloy as the joining agent. It is a variation of alumalloy which is a aluminum solder which can be used with a MAPP torch to repair aluminum lower receivers.  When I first started building 0% lowers I made a bunch of milling errors and found I could use the solder to repair mistakes. The solder is primarily zinc based and is harder than the aluminum, and hides the repair.  The only problem I found with it, is that when I sent off the receivers to be anodized the anodizing process melted the zinc, so I had some nicely anodized receivers with major flaws.

Te spike is largely due to those concerns, in my opinion.  The incident to which you refer has already happenned - the shooter in the SoCal incident a while ago used an AR made from an 80% lower, and politicians immediately started with ban proposals - there's a bill in Cali to do that, as well as congressional noise.



I'm going to use this as an excuse to finally get the oxy acetylene rig I want so I can braze the parts together.  That and a Dremel - what could possibly go wrong?

ETA: and now I'm out about $100.  Jerks.

Light up your torch!!  Silver brazing works just fine in the absence of a TIG welder.  Good bonding and nice small filets.  Check my photos above.