More On Colt Monolithic Upper History


A couple weeks ago I did the “10 years of the Colt 6940” post and then a few days after realized I had left out some pretty neat stuff from the history of the Colt monolithic uppers. Over the last 10 years there was some other monolithic upper rifles and carbines from colt in some variants that we never saw displayed at any of the shows

This rifle length barrel and monolithic rail was very interesting. It came about right around the time the USMC was making noise about putting collapsible carbine type stocks on the M16A4. Supposedly making it the “A5” Never happened and neither did this variant. I would very much like to have had this gun but with a match barrel on it for a sort of 694X SPR precision rifle.

This is sort of a compromise of a M4 with a RAS but with the 6940 type folding front site and a piston gas system. Meh.

Above is a piston version of he Colt SCW. We did later see this side folding and collapsing stock trickle out via ebay and gunbroker etc. But so far nothing has been offered for sell as a standard or special order option. Later photos of more refined versions showed a DI gas system and a full monolithic 6940 upper. The side fold stock is pretty nifty but required a much modified bolt carrier group.

The most successful of the 694x series variants for military markets is the Colt IAR. Made up as Colt’s option for the USMC IAR rifle the Colt IAR is made up with a heat sink in the lower removable handguard and barrel more suited to full auto fire. A decent amount of uppers were sold on the civilian market,Howard has one, and some other countries use the full auto military version as IARs and even a sniper support weapon in the case of Mexico. You can see a video of friend of the website Alex, shooting his Colt IAR upper on a full auto lower below


  1. Thanks to your postings on this, I’ve started nosing around for a 6940 upper. They tend to run $900 to $1000 as a complete upper, with 1:7 barrel. After thinking about what it would take to machine one myself, that’s not a bad deal.

  2. If you would’ve asked me those years back I still would’ve said Colt had “had it in the bag” for a product improved M4. The Army seemed to have cash in hand, wanted “new” and it answered the mail on the sticking points they were bringing up. When the piston variant was announced it was just extra icing on the cake during the 416 hype days. Then….nothing. Surprised it didn’t get picked up really.

    If the Marines, and Army for that matter, had went down the collapsible stock road along with the Canadians and their C7 variant early on I’d say one would have a valid argument for the M4 not happening. Well, not happening on the pure fleet issue scale it did and following the original intent instead. An A4 with an LMT stock is something you shoot all day and enjoy it.

    • around the Hk 416 hype days and all that, I think it was pretty clear the army and gov wanted anything and anyone other than colt. They seemed to be going out of their way to ignore colt’s improved carbines and rifles even though they met the requirements asked for. They had a real hard on for replacing the M4 at the time and of course Colt = M4 A new carbine was coming any day! Yet here we are and the M4 is still the best general issue service weapon


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