Interesting Colt heavy barrel

[RCS]

This Colt heavy barrel came with an early Colt upper without the forward assist. A dealer at a gun show had three of these heavy barreled Colt uppers at a gunshow back around 1990, the cost was $200 each. I bought one and used a SP1 lower to test fire at 100 yards, it grouped just like an issue barrel, nothing special. The twist was 1 in 12.

Later I traded it to a friend but took these photos for later identificationAttachment 17485Attachment 17487Attachment 17486

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[GUTS]

Possibly for this, Model 606 HBAR
http://http://retroblackrifle.com/

[RCS]

Question ? could this upper be from a Model 611 (export) or Model 616 (export) and that barrel code dates from 1970 approx ? and would the factory (Colt) still use the upper without the bolt assist and still use the three prong hider for exports ?

[jmoore]

IIRC, the Colt LMG upper had no forward assist but did have a brass deflector, but I haven't seen one in a couple of years. Front sight tower has the gas tube hole and "cross bar" higher up, so no dog leg in the oversized gas tube. It's one check that could be done to this barrel assembly.

No bipod provision on the barrel, though, so probably not an LMG upper. Hmmm. Gonna have to cipher over this unit a bit.

[RCS]

Mr Moore, Thanks for your help. One thing that I did notice about this Colt HBAR upper & barrel, is that the small hole take-down pin is used - would this indicate military ?

[GUTS]

The barrel profile and the Type two flash hider indicate to me that they are 606 uppers although the flash hiders could have been changed out at some time. The 606 upper had no FA and no brass deflector.

[RCS]

Jeff, If this upper and heavy barrel are from a Colt 606, would it be considered common or kind of rare ? are these Colt 606 upper/heavy barrel units around ?

[GUTS]

The Retro Forum that I am on most has had members build almost all of the different retro models but I don't remember ever seeing a 606 built. It is actually a Model 604 with a heavy barrel. The measurement of the barrel under the FSB should be .750" and the barrel should be stepped but not tapered. The 606 also had a white plastic buffer, a BC that was parked and had the FA serrations(although the rifle did not have a FA), and a bolt that was either parked or chromed. If those are actual 606 barrels it would be fairly inexpensive to build them back into original looking rifles. All that would be non correct would be the NDS partial fence lower that you would buy to complete the rifle. I don't know how "rare" they would be but they would definitly be very uncommon. Here is a photo of one:

If the barrels have a taper from the chamber to the muzzle they are probably from a later rifle.

[GUTS]

Mr Moore, Thanks for your help. One thing that I did notice about this Colt HBAR upper & barrel, is that the small hole take-down pin is used - would this indicate military ?

The small hole and the vintage of the uppers indicates military surplus but without seeing the Colt proof marks to the right of the ejection port, all that the small pin would positively tell is it was a pre ban or a post ban upper, different companies have made copies of the most of the styles of A1 uppers over the years.

[RCS]

Jeff, I was able to check this early upper and heavy barrel over this weekend. The upper has the Colt triangle and square C in front of the ejection port, no FW or brass deflector. The ejection port cover looks just like the 604. The slip ring is flat. The rear sight drum has only an arrow R.

The barrel is .680 at the muzzle, .715 in front of the front sight base and .750 between the bayonet lug and swivel. I checked the barrel again, it is 1X12 twist. The barrel has the exact profile as your photo of the Model 606 profile. The handguards are the glossy black triangular.

I have plans to get this upper/heavy barrel back as I think it is kind of a rare item. Thanks for your help and posting the photo of the 606 barrel profile