Was there ever a Colt CAR-15 open bolt design?

[alvin]

I had acquired a NIB Colt 6520 green label years ago from a bankrupt FFL dealer. The gun was later sold to a new collector. In general, he's happy on the condition. But, he carried the gun to a local gun expert, and the expert told him, "Weird, this carbine should be 'open bolt', but this one is 'close bolt', which is much less collectible......"

So the buyer came back to me asking "where is the correct bolt?"..... "Sorry, I don't have it, and I have never heard of such a thing on Colt CAR"..... The buyer still decided to keep the gun. But asked me "Did you wrongly install the bolt on it during assembly?"

Of course not, I had only one Colt, and that's the only one. But this 'open bolt' argument confused me. From the expert's statement, sounds like open bolt CAR was not a prototype, it's something in mainstream production..... Semi-auto CAR-15 with open bolt?? I have never seen one ...... was there ever such an 'open bolt' CAR-15 design?

[Patronen]

I don't know about the CAR-15, but the M231 Port Firing Weapon for the US military fires from an open bolt but that is an Automatic rifle based on the AR.

Dave

[sheepherder]

Colt also made a 9mm smg for the DOE that fired from an open bolt, but that bolt would not function in a 5.56mm carbine/rifle.

There are real experts over in ARFCOM/Retro who can tell you more [http://www.ar15.com/forums/f_3/123_.html] but basically your 'local gun expert' is blowing smoke up your butt...

[alanint]

In short, NO.
This "Expert" is trying to low ball somebody and any open bolt design dropped into a semi-auto would get immediate ATF attention.
There is an "Open Bolt" kit that can be installed in the standard M16. It was designed by Colt when they put forth a heavy barrel rifle as a SAW, (Squad Automatic Weapon). The goverment never adopted the Colt offering and the original specimens out there are worth more than a standard M16. The open bolt design is extremely hard on AR15-M16 lowers, as the operating parts pinned in the lower are used to stop the bolt from going forward, thus eventually opening up the pin holes in the lower and causing pins to "walk".
This "Expert" is completely ignorant of this weapon system.

[padredan]

the military had what was called xm177, i believe was the model number or car16, was a select fire weapon, not sure it was an open bolt, but had around a ten inch barrel with a flash hider and colaspable stock. more or less the forerunner to the m4. This would not be what you are talking about as it would be a class three weapon, therefore a machine gun.

[alanint]

I own both an XM177E1 (Army, 10" barrel) and an XM177E2 (Army, 11.5" barrel) and neither work from an open bolt. The M16/AR15 systems are closed bolt systems. Period.

The only exceptions are the one I detail above and the rare M231 Port Firing Weapon.

[padredan]

Well i did remember the model number and the barrel length. Been over forty years or so since i saw one. I do remember they were very loud and had alot of muzzle blast. I often wondered if they were colt made or armors had built them.

[padredan]

http://www.gunbroker.com/Auction/Vie...Item=277309416
this would be it, i believe, as has been pointed out , it would have NEVER had an open bolt, so called expert is not.plenty of those around.

[alanint]

The XM177 System began life as an Airforce Survival rifle. The system retained its "X" designation throughout its service life as it was never officially adopted and remained "Experimental" on the books.
The original Airforce version, (XM177) had no forward assist, as the Airforce did not require it. This gun had a 10" barrel. The Army got interested and the XM177E1 was produced for them, with a forward assist. This was originally meant for Special Forces, LRRPs, etc. but they suddenly began to be in demand by regular Infantry officers as a "badge of rank". People were scrounging from everywhere trying to get one. As you mention, the guns had a 4.5" "sound moderator", which was meant to regulate the gun's report down to that of the standard 20" rifle. Anybody who has heard the standard rifle and one of these Carbines side by side would know how dismally this failed. The moderators would soon clog up and the report would rise accordingly. The enemy soon realised that that louder report was coming from an officer's carbine and focused their interest accordingly.
There were a number of reliability issues with the 10" barrel, so they fielded the XM177E2, which had a new 11.5" barrel and a "Grenade Launcher Ring" placed between the muzzle end of the barrel and the sound moderator. Despite the ring's description, it was not meant as a gas check for a muzzle mounted rifle grenade, but to hold the front end of an M203 Grenade launcher under the barrel of the gun.
This gun was most successful with MAC-SOG, LRRPs, and Special Forces, whose job was to sneak and peek and not to hose down opposing troops. It's small size was ideal for these behind the lines troops and the added muzzle blast and noise were beneficial when initiating or responding to an ambush. The gun was never oficially adopted, but the concept evolved into the M4 series of weapons.

[sheepherder]

Originally Posted by alanint

The only exceptions are the one I detail above and the rare M231 Port Firing Weapon.

...And the 9mm Colt M633...(Adopted by the DOE)...

[alanint]

Yes, but I don't consider this an "AR"

[sheepherder]

Originally Posted by alanint

Yes, but I don't consider this an "AR"

A few years ago, when I was heavily into 80% receivers, I did several clones of old AR's...The M633, the XM607, and a 'fantasy prototype' based on several of Reed Knights collectibles...All in 5.56...

The 5.56mm M633 clone is a crowd pleaser...

[alanint]

All nice replicas!! I've toured Reed's collection and it is quite impressive. In fact, the last time I visited I was in the company of General Kalashnikov, who remarked that he was also very impressed with Reed's collection, but puzzled by the lack of AK variants. Reed has no Ak variants in the lot!!

The M607 should have a 10" barrel and the first issue sound moderator with no flash hider, but pretty close!

This is a great site for parts, accessories and resources for these early replicas;

http://retroblackrifle.com/

[saab-bob]

Alanint
Did you get General Kalashnikov to autogeaph one of your AK's??
Bob

[alanint]

Well, we did pal around a little.....



Taken in the Lobby of Reed's building.

[alvin]

Thanks everyone!

It took me some effort to explain to the buyer that "close bolt system" was normal on CAR15. I did not know Colt, nor AR15, so it was challenging. Look back, intuition was correct -- no benefit for a semi-auto carbine having a open-bolt design. Luckily, the buyer did not return it back to me. It cost a couple of grands, usually people are very sensitive on expensive items, especially when he heard something negative from another guy. That's understandable.

That's back about five years ago.

[alvin]

Originally Posted by alanint

Well, we did pal around a little.....

Taken in the Lobby of Reed's building.

Two thumbs up!

[padredan]

outstanding Doug, just how old is that old russian now? has to be in his nineties.

[alanint]

As durable as his invention.....

[sheepherder]

Originally Posted by alanint

This is a great site for parts, accessories and resources for these early replicas;

http://retroblackrifle.com/

TexSquirrel's site is OK, but ARFCOM/Retro has it beat, hands down...(I wish more people would frequent TexSquirrel's site; but ARFCOM is just too well established)...

(TexSquirrel rescued the RetroBlackRifle site, if you hadn't heard)...