AR Sponsor
Posted: 6/26/2006 8:14:31 AM EDT
|
I bought two of the uppers for the group buy. Both are grey and one didn't have the forge code, just the verificaation stamping and the coutnerbored front pivot pin hole. I stripped this upper and put my XM177E2 barrel on the upper and took it out shooting this week. I was somewhat concerned about how it would work (see my thread about my XM177E2 clone for the issues I have with it) but my main M4 had the Phantom flash suppressor break so I figured I'd give this one a shot for the rest of the class that day. It held up great, not one problem with it. I take it apart today to clean it and get ready to refinish the barrel and lower reciver so as per usual I hit it with break cleaner. As I am wiping it down I see that the finish is bubbling off and wiping away! I thought this upper was a bit odd when I got it as on the inside of the reciever there was a green zinc chromate looking finish. This also came off. I'm not upset about this, just curious, I'll just refinish the entire thing in Norrels now.I have no idea what it is, the finish that is. I'll see about getting pictures later tonight. Ekie explained what my issue was. For what its worth I did ask for the XM16E1 upper but I didn't think it was refinished which is why I was surprised. I'll try stripping the finish a bit as per Ekie's instructions. No misunderstandings here, I am still very very pleased with my uppers as everyone else seems to be. Steve |
|
That is an old 6061 alloy XM16E1 upper. What you describe is normal. It had been refinished, and the refinish paint job will sometimes come off with a mild solvent. I would not paint it, sell it to someone who wants it. Heck, I will trade a modern Colt 7071 A1 upper for it, provided it ain't all pitted. Be careful stripping it, have had them corroade in acetone, apparently there is some bronze in that alloy? ETA Looks like I am to late on the don't paint advise. |
|
There were 2 of the Uppers out of the lot that I believe are exactly as EKIE described them, I am pretty sure that they were the early forgings. The finish on these 2 Uppers seemed to be different than the others. Given everyone was expecting an Upper with a "C" and "H" Forge Code, I kept one and you ended up with one. I have wiped that Early Upper down with CLP, and had no problems, but I have not used any type of solvent on it yet. The other Upper I got with the "C" and "H" Forge Code has been cleaned with a solvent and has done fine. Everyone might want to double check your Uppers, but I am pretty sure everyone else had the "C" and "H" Forge Code Uppers and should be OK on the finish. The finish color on these Uppers did vary, so there may be some variation in the finishes on them. Thanks, “Capt Richardson” |
All XM16E1's were 6061, and so were the first year of M16A1 production (1967). Stoner insisted on using 7075, but Colt went their own way until they found out they were wrong. Good news that you have not refinished it yet. Don't worry about what you took off with brake cleaner that was just cheap paint a GI sprayed on it. I recommend that you leave it as is, take it outside and take some good pictures of it so we can see what kind of shape it is in. Like I said before, I would be interested in it, as long as it is not pitted, and so would other collectors. Here is an example of a XM16E1 upper that was painted during a rebuild. I succefully stripped it with acetone and a brush:  Was less successful on another upper, it would not strip easily so I soaked it in acetone overnight, and it corroded. |
|
So about an hour with an issue toothbrush and brake cleaner and it's 98% gone. The finish is pretty rough. No pitting but the dark grey is mostly gone. It has a heavy light gree tint to it and the edges are almost all bare aluminum. It looks like it did a tour or two in Vietnam or served a hard life as a basic training rifle. I'll see what I can do about getting some pictures. Steve |
I have seen hundreds of demilled XM16E1 uppers , and they all seem to show "flaking" of the anodising - this looks like tiny bubbles that will eventually flake off , and i have seen some that were covered in a "powdery" residue - and were horribly corroded - i have no idea why some of these XM16E1 uppers seem to corrode faster than others but i have observed this , i have a sneaking suspicion that some of these uppers were made from a "hot pressed casting", maybe metal experts can chime in and tell us , but here are some photos of what im talking about :  |
Thats rough.. looks like a fat chick in a bikini  Well it appears my upper is in decent shape then as there is not corrosion that I can see. There are one or two divits on the sides but I can't tell if it's corrosion or if it's just a dent, looks like a dent as they are fairly large and in dentable areas. Steve |
Machine , they have a partial countersink hole in the front left side of the receiver takedown pin hinge , and they will not have any forge codes inside the rear sight recess area , and most - but not all will have a tiny triangle and a C inside a tiny box - just forward of the ejection port -- and from my perspective are made out of a inferior aluminum - and crack very easily(they are extremely brittle) , and corrode. |
That is typical. Not a "casting", they have always been forgings. Reason some are corroded, and some not, is that some went to Vietnam, and some did not. |
Cool beans, we want to seem some pics. Not sure what to make of the "dents". |
Ekie , these receivers don't weld like typical 6061 aluminum - you will get nothing but "weld porosity" in them if you try and TIG weld repair them - just like a porous casting would react ? - this is why i say this - i have welded 6061 aluminum stock before , thin & thick , and it does not react the way that these XM16 uppers do - maybe there is another explanation ? |
Difference between forging and an extrusion. |
Yours looks great ! , i have seen some of those in absolutely horrible condition , and allot that were demilled -- Maybe Ekie could answer this question , but i was wondering if the military simply replaced all of the XM16E1 uppers - with complete new upper receivers with the Chrome chambers in the Vietnam '68-69 time frame - or did they keep the XM16E1 upper receivers , and just replace the stripped barrels ? ---- i have heard "rumors" from a vietnam vet friend of my dads that they trashed the whole XM16E1 un chrome lined barrel unit , and replaced these in NAM wit a complete Upper assembly with the chrome chambers 
|
|
I-LUV-AR15s, The finish on your upper looks like it is probably Sandstrom, aka. Solid Film Lubricant. Some claim that it is used by the Govt to refinish rifles but it is only authorized as a touch up finish for use at the field level. Though CONUS support units, Reserves and training units are authorized to cover entire uppers with it, as they theoretically aren't as likely to deploy. Annsiston(Depot) does not use it on major components for true refinishing because, as you have discovered, it is not very durable. It's more liken to the finish on magazines. Never really becomes hard and will come off on your hand to some degree when fingered enough because it is a dry lube. Some of the later batches resist this more than the early stuff does. Though it does make old components look new for a while. Not to imply there was deception on anyones part on these, they were probably touched up/finished prior to being put into storage at a local level(not Depot) before they were stripped down and surplused. I'd strip it off to see how bad the original finish is underneath. Wpns Man |
That is really nice, but it is refinished. On 1960's uppers the front lugs, rear lugs, and the inside of the carry handle were taped off on the prefinish blast job. These areas came out black, while the rest was a matte green or brown gray. Another thing to consider on these old uppers, is that the vast majority of no forge code uppers with forward assist are M16A1 uppers in 7075. Colt made some 2,000,000 if these, while less then 600,000 XM16E1 were made, |
Wpnsman is better qualified to answer that, but no, barrels are replaced based on how they gauge, not what type or era they era. |
Don't know nothing about welding, just know that USGI uppers and lower are forged. |
If you have an old forward assist upper, with no forge code, and a counter bored front lug, only know of two ways to determine it's alloy. If it is corroded, it is 6061. If it is part of a original and complete upper you can date it with the variation guide. |
Ekie, The smoothside upper on my Air force M16 clone is one of the early types w/the counterbored lug and no forge code. Can I assume that it too is 6061?  Since I obtained it in just about brand new condition, finish wear and possible corrosion simply weren't an issue.
|
It could be either, did it come with the original barrel, if so we can date it. |
|
A very interesting thread going on here, and I just found out a lot about an upper I have. Check it out: http://i80.photobucket.com/albums/j175/speedreid01/100_0039.jpg http://i80.photobucket.com/albums/j175/speedreid01/100_0040.jpg It has the black front and rear pin bosses, the counterbored hole on the left of the front pin boss, no forge marks under the rear sight, and the "square and triangle" stampings on the right front. Guess I've got an XM-16E1 upper on my hands! I tested the finish with brake cleaner, and it held fast, nothing came off on the cloth at all. Best of all, no corrosion on this unit. I was planning on making a "Blaster A1 Carbine" upper with this, but now, maybe not. Hey Ekie, if you'd like to trade me for a nice Colt gray A1 upper, I'm game. Please email me if you're interested. |
| Now for a question (or two): While I now know the early Colt upper receivers were 6061, later switching to 7075, what is/was the scoop with the lower receivers of said rifles? How about the AR-15 Model 614, were the upper and/or lower receivers 6061 on these? Thanks for the very informative and interesting post, fellas! |
I would try using acetone or MEK and see if anything comes off. |
Nope. Just the upper, w/sights and cover. Thing looked about new, but did have the Colt acceptance stamps by the ejection port, so I'm assuming it was demobed from a complete rifle. Anodized color is a perfect match for the 1976 SP1 lower at my house, and the even later commercial (big hole) forward assist upper---if that's any help. Also, the lugs are the same color; not black 
|
Uppers and lowers were 6061, they were changed to 7075 in 1968. So depends on the year on a 614. |
Considering the lugs are not black, then it should be a 1970's part, and thus 7075. |
AR Sponsor