Thoughts on an old AR upper reciever - Printable Version +- MetalworkingFun Forum (http://www.metalworkingfun.com) +-- Forum: Machining (http://www.metalworkingfun.com/forum-5.html) +--- Forum: Gunsmithing (http://www.metalworkingfun.com/forum-27.html) +--- Thread: Thoughts on an old AR upper reciever (/thread-2414.html)

Thoughts on an old AR upper reciever - alanganes - 12-19-2014 I posted this same question on another forum, but thought I'd get some input from this group as well: So I am idly contemplating building myself an AR rifle of some sort. Kicking around my place I have an old AR upper that was given to me somewhere along the way. I've had it for years. It's the type with the integral carry handle and no forward assist. No markings that I can recall. If I build another AR, I'd prefer to have the flat top style with a rail or whatever rather than the top handle (I have one of those already) upper. Would it be crazy to cut off the handle and mill a flat surface to affix a rail for mounting optics? I know uppers are not so costly that this makes huge economic sense. It's just a project, so cost effectiveness is not really the point. Other than the fact that I could probably buy a new one for what my time might be worth, is there any other compelling reason not to do such a thing? Is there a technical reason? Are those old uppers so wonderful that this would make me an awful person? Thoughts?? RE: Thoughts on an old AR upper reciever - dallen - 12-19-2014 its yours, and from what your saying its not a collectors item, so if you feel like you want to chop the top off of it have at it, mill it flat and screw on or weld on a rail. Structurally, you should be fine unless you cut completely into the slot the charging handle runs in, heck people cut slots down the side so they don't have to have the charging handle on to of the carrier. DA RE: Thoughts on an old AR upper reciever - alanganes - 12-20-2014 I don't really "think" it's a collector piece. I do know that the original Armalite AR did not have a forward assist but have no idea is this is that old or even an Armalite part. RE: Thoughts on an old AR upper reciever - Highpower - 12-22-2014 Is it an A1 or A2 style upper?  The A1 uppers are getting harder to find and wanted by folks who want to build "retro" Vietnam era rifles. Does it have a shell deflector behind the ejection port or not? If it is an A1, I might be interested. I have a brand new A3 flat top receiver sitting here.....  "Back in the day", Frank White of Compass Lake Engineering was cutting off carry handles and milling in scope mount rails on AR receivers for long range shooters way before anyone ever even heard of a flat top receiver before. They soon caught on.    A1:  A2:  A3:  p.s. They are all made from 7075 T-6 aluminum. Non-weldable. RE: Thoughts on an old AR upper reciever - Highpower - 12-22-2014 Alan, I just found your post and link to the pictures on the other forum. FYI: What you have there is a very early Colt A1 upper receiver. These were mated to a "slab sided" (no fence around the magazine release button.) Colt lower receiver. The letters C  K inside the valley below the rear sight hole, and the larger pivot pin hole identify the receiver as a Colt. C = Colt (manufacturer), K = Kaiser Aluminum (foundry that made the forging). Colt was the only manufacturer to use the larger pivot pin AFAIK. Sell or trade this receiver but don't cut the handle off of it. There are tons of flat top receivers available out there. Your early A1 receiver - not so much.  RE: Thoughts on an old AR upper reciever - alanganes - 12-23-2014 Thank you for taking the time to reply, Willie. You managed to find the photos (linked here: http://smg.photobucket.com/user/alanganes/library/HSM_Board/AR%20upper ) before I got around to posting them here. It's been a bit confusing around my place... Excellent info  there, and I'm impressed that you picked up on the "C" and "K" molded in the side. I have no idea how many times I have looked this thing over and never noticed those before. The light as to be just right for me to pick them up. Some of the replies and a few PM's I've gotten already prompted me to discard the idea of modifying it. One of my son's sort of wants it to do a build, largely because of the connection to the guy I got it from. So that's what I'll likely do with it. Info like this is exactly why I asked the question. If this was just some garden variety piece that was nothing in particular, I would not feel too bad about modifying it, but this is reason enough to just use as is. I sort of like the look of the older AR's. The one I have now is closer to that style, A1 upper with a forward assist, triangular handguards and such. Not 100% in every detail, but close enough for me. Decent shooter as well. Probably gonna have to find a slab side lower now.... Thank you again for the info. Most helpful!! -Al RE: Thoughts on an old AR upper reciever - Highpower - 12-23-2014 Think nothing of it Alan. We share what we can when we can. I like the older AR's too. I've been wanting to build an A1 myself for quite some time now. I do have a factory Colt AR15-A2(HB) that was a transitional model. It has a slab side lower on it. I don't want to break up an original rifle though, and will make my own lower for the A1. One of these days.....     I even have an extra set of M16-A1 furniture sitting here if your son finds he can't locate any. (Short stock, straight pistol grip, triangular hand guards.) FWIW, I've seen some pretty cheap prices on stripped flat top upper receivers lately. I don't think you'll have any problem finding one if you want to do your own build as well. Best of luck in your quest!