I am looking to purchase a NIB 1978 Colt AR 15 SP1, but I am concerned with the authenticity as the seller states it has an auto bolt carrier. My understanding is that the SP1's only came with the semi auto bolt carrier.

Is it possible that Colt made a 1978 SP1 with auto bolt carriers?

Thank you in advance for your help!

With Colt, all things are possible, because they basically built the SP1s with a lot of leftover parts from the military production lines, other than the lower receivers. It's not likely, but not certain that a 1978 might not have come with a full auto carrier from Colt.

As long as it's a "C" marked carrier, IMO.

Also, is the seller sure it's an auto carrier? (as in he's taken a pic and shown it to you?). It's possible the seller just doesn't know what they're talking about.

I've never seen an original SP-1 with an auto carrier but I suppose it is possible. Unlikely though. If it's gonna be a shooter, who cares though. The auto carrier is better balanced anyways.

Thank you for the quick input. He is going to send me a picture to verify, but he's confident it is an auto bolt carrier.

This would be a NIB, never fired, safe queen that would be $3000 shipped, so I do want to make sure it's 100% original before buying. It's hard to find the 1978 and older SP1's in mint condition with box, paperwork, and accessories.

Thank you again!

Yeah that’s a bit of a different story haha.

I had to buy a Colt FA BCG for my SP1.  As noted, it’s Colt, so, maybe....

Is he the original owner?

Doesn't pass the smell test to me. I wouldn't spent $3k on a "maybe"

Agreed.

My 1977 SP1 certainly doesn't have one, and I've never seen an original SP1 with a FA carrier.

Possible? Yes (anything's possible...)
Probable? Not hardly

For $3K (which is ALL the money for a 1978 SP1 in that condition) I'd want more than a "maybe".

I still haven't received a response from the seller on this, so I'm guessing there is something fishy about this. He was selling for $2900, but after shipping and transfer fees it would've been closer to $3000.

I've been searching for a NIB, 1978 or older Colt SP1 for quite a few months now, and I've only had an opportunity at 2 of them which I was outbid on Gun Broker (went for over $3300).

Any recommendations on where to look other than Gun Broker? Thanks again guys for your help. I will not be buying this rifle.

I could be wrong but I was under the impression that Colt specifically had the SP-1's and SP-2 ship with the AR15 type carrier as requested by the ATF? I mean its feasible but I doubt anyone would let a Sporter leave with an M16 carrier.
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The EE. And GB prices are inflated. At that price point, you would be getting into 3 to 4-digit 1964 and 1965 guns.

I have a 1977 SP1 and it came with a semi auto bolt carrier

It looks like he lowered the price on this, but still hasn't sent me pictures of the bolt carrier.

https://www.gunbroker.com/item/868624841

Looking at the upper and lower, it is normal to be so discolored? Would oil bring that finish back?

I'm really trying to find a NIB Colt SP1 1977 or 1978, and this is the only one out there with all of the accessories.

Your feedback/opinion on this is appreciated!

Doesn’t pass the smell test for me. My 1978 SP1 had a semi auto carrier.

Same here. I bought mine new and it had a semi auto with serrations.

FWIW, I was checking on a Colt bcg that came with a SGW Oly produced rifle back in 1984.  It came with a complete M16A1 upper CH, C MP Chrome Bore.  But it had a AR15 style slick side bcg marked C.  I had assumed Colt only made M16 bcg's.   retroblackrifle.com shows that the SP1's originally came with AR15 slick side bcg's.  But it also shows that afterward they came with fa M16 bcg's.  Not sure how accurate this information is, but thought I would pass it along.

My bcg

No. No. No. While it's impossible to prove something didn't happen, Colt DID NOT just throw together SP-1s from leftover M16 parts from the "military production lines."
If that's true, why didn't we see any SP-1s with select-fire FGCs, etc.?

Because no Sporter ever left Colt's with any military/full-auto parts, period. Even the hammers weren't ground-down M16 hammers, they were semi-auto from the get-go. If that ever happened, which is extremely doubtful, it was an unauthorized act by an employee too lazy or careless to open a box of the semiauto part, and managed to slip by whatever QC Colt had in place.


Colt has kept sloppy records and it's true that they have been known to deplete inventories of old parts before switching to a newer spec (Colt Government models, for example, that started with A1 uppers then switched to A2 uppers with no fanfare whatsoever).

Does anybody really think that, after having to jump through multiple hoops to please the ATF including designing a completely different lower with different sized pins and a bolt carrier specifically designed to pass muster with the ATF, that Colt would just blow that off and put full auto parts, i.e. bolt carriers, in an SP-1? Well, obviously some people think that, but you have to wonder why Colt would blithely risk the wrath of the ATF during the CARTER ADMINISTRATION? The same idiot who made the military stop using the XM177 flash hider because he thought it made the gun quieter and that was somehow cheating? And then had the ATF classify that FH as an NFA silencer? You think Colt would risk pissing off that guy? And if that's not enough, at the time (don't know about now), Colt actually had a couple of dedicated ATF agents literally stationed in-house. Seriously, does anybody really think Colt would risk stepping on that land mine? Come. On.

It's amazing that after all these years and not one proven instance, that people persist in perpetrating that gun-culture myth of full-auto parts in AR-15s.
I have owned several ARs from the 60s and 70s that were LNIB complete with the original 5-round blocked mags, hang tags and the tampon in place, and never saw anything but semiauto parts.
I have an AR with a three-digit serial number from 1964, and it has a chrome bolt and park'd semi-auto bolt carrier just like in every single verified picture of such.

My guess is that that people are getting the early BC with the milled-out underside confused with the FA version. They look similar, but when you see them side by side it's pretty obvious.

IIRC, it wasn't until after the AWB expired in 2004 that the ATF finally relented on the M16 BC issue.

Puh-leeze.

I have a 1978 Colt SP1 which I purchased new.  I also have a 1975 NIB SP1 complete upper receiver assembly.  Both have C marked semi-auto bolt carriers with serrations for forward assist, although obviously neither upper receiver has a forward assist.  I can only assume, perhaps incorrectly, that the SP1 bolt carriers from that time period were originally M16 bolt carriers that were modified by Colt to semi-auto specification prior to finishing.

Colt started cutting ALL carriers with forward assist serrations in 1967.

I see it’s still on GB and it’s an SP1 carbine, which is rarer than the rifle, having been released on September 27, 1977 vs January 2, 1964 for the rifle.

I think the colour and variation comes from the fact that it looks very dry. Some oil and TLC should make it look great.

If truly NIB it’s a nice carbine IMO.

Here’s my 1980 one, in very good condition although it has some non original parts (it was modified for FA fire)

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True. The AF was using 604s (M16) which had no forward assist, but somehow the un-cut bolt carriers kept turning up in 603s (XM16E1s & M16A1s) which caused problems.
Because the reverse (a slotted bolt carrier in an M16 without FA) wasn't true, the decision was made to cut all the carriers.

As to why Colt went to the trouble to cut the civilian ones, too, perhaps they thought that if the military was having that problem, so would the civilian market - except that civilian customers don't have a unit armorer to complain to.
So perhaps in order to prevent any number of customer complaints, Colt decided to make the change across the board.

Once again, Colt didn't just grab military parts off the line, modify them and toss them into civilian production bins. And looking at AR-15 semiauto bolt carriers (and other parts) I don't see the mismatched machining marks that would indicate multiple machining steps. By comparison, I've seen many off-brand guns from "back in the day" (before there was much in the way of parts production for the civilian market) where manufacturers had clearly taken military surplus parts and neutered them. Examples would be hammers where the auto-sear hook had been milled off, disconnectors that had been bobbed and selectors where the middle lobe had been milled away.

My SP-1 carbine from late 1970s came with a Colt shaved semi BCG.

Every one I’ve handled (maybe 6 or 7 I was considering buying in my life) had Colt semi BCG.  My SP1 carbine now has Colt chrome BCG I found in a box of used parts & the guy wanted $50.

But I do know Colt is/was schizo enough that connected people got whatever they wanted.

Someone more experienced will chime in.

Wow, and I was going to part mine out...maybe it’s worth more assembled...