I'm a newbie to transferable M16s. Would one day like to get a factory M16 gun, but I'm still learning the important details, pitfalls, etc. with the factory Colt M16s.

Anyway, can someone tell me what the likely story is with this gun:
https://www.davidspiwak.com/gun/colt-m16-factory-hybrid/

If I'm not mistaken, the IRS serial number means it is an amnesty gun, but it seems interesting that it is marked AR15 rather than M16. I wouldn't think a bring-back would be marked AR15. It looks like it does not have the oversized front receiver pin, so I suspect it might have actually been a factory gun. Any ideas of how the gun came to be?

A couple other newbie questions:
-how does someone identify a welded rewat? I've read that some of those supposedly are on the registry.
-why do the safety and the rear receiver pin have dimples in the ends? I haven't noticed that before, but it might just have been something I had always overlooked before I started paying attention to the granular details.

I think some of the early M16 receivers were marked "AR15".
This could be one of them, as Colt never threw away any parts that were no longer used in their U.S. military contract guns.
Such parts would appear on later foreign sale guns as well as civilian guns, both full auto and semi auto.

Perhaps someone from the Retro Forum will pick up on this.
Some of those guys can tell you all about the generations and variations of pins, selectors, mag releases, bolt releases, furniture, rear sight wheel, etc.

EDIT: I put a link to this on the Retro Forum.

M16

RCA

The takedown pin/safety with "holes", that's the way the early ones were. Don't remember if I ever heard as to why. As to the early flatside receivers with the Colt Ar-15 Rampant Colt markings, I've seen several examples. Normally you'd see stamped under that USM16A1 with the serial prefixed by SER. under that.  In a batch of 200 from ANAD, these were DRMO guns to a LE agency, right out of the wraps there were several of these. One had XM177E1 but did not have the stock/barrel for that, it was an 20" pencil barrel A1 with an A2 stock.

I know is happens that Colt will use guns for demo models, armorer use for teaching, trade shows, etc and then down the road sell those. Wouldn't mind finding a Port Firing M16 but I suspect all of those disappeared to the winds....

I appreciate the effort. I've never been to the Retro area before, so thanks for cluing me into it (this site has the most labyrinthian forum structure I have ever seen). That said, I read the other thread, and wow. Hopefully it isn't always such an explosive tender box. Makes GD seem even-keeled.

There are many Colt AR15 marked factory MGs. These are not SP1s, they are factory M16 spec guns.

The most commonly seen is probably the model 614, but there are many others.

I’d venture a guess about the gun in question, that it was 68 amnesty registered, someone had scrubbed the serial number and probably the US propert markings, so an IRS serial number was given for the registrant.

Retro forum is pretty civil.
Never seen anything that un civil.
I suspect it is a bleed over from the General Discussion forum.

Anyway, the knowledge on the retro forum is pretty impressive, and is my first stop when I log in.

I don't have anything that would really qualify as "retro" but I do have a couple that might be termed "retro-ish" or "retro-inspired".

RCA

If you buy it, you'll like it.
When I bought my Colt M16a1, I looked at conversions, other brands, etc. and decided to pay extra for a Colt as you just don't hear about many problems with off axis pins, out of spec areas of receivers, etc. as you do on some of the other brands and even Colt SP1 conversions.
I think in the long run, a Colt will appreciate more than the above mentioned.
And that one seems to have an interesting story to tell.

RCA

To put it bluntly, that thing is a hot mess...a hodge podge of parts from different era's and the receiver is cosmetically fubar.

For 30k, you can get yourself a much nicer Hartford Horsey my friend.

Agreed. Unmolested colt m16a1 are going for $35-37k. $30k is too high for the gun in question.

Thanks. I wasn’t really interested in it to own. More so trying to figure out what is going on with it. I know there are lots of pitfalls for the uninformed in this game, so trying to put my student hat back on. I’ll probably look to buy in the new year, but I’ve seen some pretty good deals lately.

Machine guns in general, and good ones like Colt M16s in particular, only increase in value with time.
Don't wait too long.
What looks like too high of a price today becomes a heck of a deal in hind sight.

My advice is buy an original Colt M16 registered receiver.
Much less likely to find anything out of spec down the road.

But as with any high dollar purchase, do your due dilligence.


RCA

Thanks for the insights. I've got a few other transferables and have been following the market for awhile now. It seems to me prices have softened a little bit over the past 6-12 months ago after the meteoric rise in the COVID era, but I know that the overall trend for MGs is up up up.

I am planning to get a factory Colt, probably an M16A1 or equivalent (still figuring out some of the various 600 series models) or a carbine, though carbines seem to command a higher price, and it is easy enough to swap the buttstock/buffer tube assembly.

One question I have had is whether it is actually possible to tell if a receiver has egged pin holes from pictures, or whether you would need to see/feel it in person? I occasionally see RRs sold with a 9mm upper, and it makes me a bit nervous.

There are many things wrong with that M16 in your spiwak link. The potato pics really do not show it well. Not anywhere near what he's asking.

When and if you do find a deal you are interested in, you should insist on very high resolution pictures of the pins.

If the receiver is equipped with anti-walk pins, (with anti walk pins, screw heads cover the contact area with the receiver) that might be an indication that it has been fired with a blowback operated pistol caliber upper.

Once again, as with any large purchase, it is incumbent on you to do your due diligence.

RCA

I remember a while back his website had a colt sp1 conversion with a IRS serial number that claimed to be involved in the bay of pigs conflict.

You would think he would know the Bay of Pigs was 3 full years before colt sold the 1st SP-1.