Adding M4 feedramps to A1/C7 upper

[scottryan]

I will have to retract my statement and correct myself by saying that some of the 700 Series carbines (727 and 733) did have extended carbine feedramps. Soon after working on carbine versions of the M16A2, Colt found that M855 fed low due to various reasons. To maintain reliable feeding, the feeding ramps in the barrel extension were lowered into the upper receiver. The extended 700 series Carbine feed ramps are shallower than the feed ramps used on the M4/M4A1 (date app 1988-1992) and are commonly found on 727 and 733 Carbines/Commandos. Standard rifle feed ramps (on barrel extensions) were used on 600 series Carbines and can be found on 700 series Carbines as late as 1990.

That is not complete information.

Any carbine made after 1994 has full size M4 ramps. There were 723 made as late as 1997 and 733s made as late at 2000.

There was also a run of 6320s made in the early 2000s that have full size M4 feeramps.

[Renegade04]

That is not complete information.

Any carbine made after 1994 has full size M4 ramps. There were 723 made as late as 1997 and 733s made as late at 2000.

There was also a run of 6320s made in the early 2000s that have full size M4 feeramps.

I would like to know where you came up with that info on those dates, especially on the 723. It is inconsistent with what I have read from credible sources.

[scottryan]

I would like to know where you came up with that info on those dates, especially on the 723. It is inconsistent with what I have read from credible sources.

Because I have a 723 sitting in front of me with a 1997 barrel date with a charcoal black upper and a 733 with a 2000 barrel date and C A forge code black upper. Neither of them have F marked front sight bases.

They also made 727 carbines up to 2001.

Example of a late 1990s 733 is seen here

http://autoweapons.com/photosv/npostm16a2comm.html

[Renegade04]

Because I have a 723 sitting in front of me with a 1997 barrel date with a charcoal black upper and a 733 with a 2000 barrel date and C A forge code black upper. Neither of them have F marked front sight bases.

They also made 727 carbines up to 2001.

Example of a late 1990s 733 is seen here

http://autoweapons.com/photosv/npostm16a2comm.html

How about pics of the 723 and 733 and pics of the receivers, not the barrels, showing M4 feedramps.

[Circle_10]

Out of curiosity, anyone know when the Diemaco/Colt Canada guns started being made with the M4 style feedramps? Based on what I've read thus far the old carry handle C8 carbines (Which is what I'll be trying to approximate with this build.) didn't have them but the current Colt Canada C8SFWs etc do.

[the_1iviper]

Out of curiosity, anyone know when the Diemaco/Colt Canada guns started being made with the M4 style feedramps? Based on what I've read thus far the old carry handle C8 carbines (Which is what I'll be trying to approximate with this build.) didn't have them but the current Colt Canada C8SFWs etc do.

i don't believe m4 ramps showed up in the c8 until the dutch army requested them in a contract with colt canada when they upgraded the carbines back a few years , maybe 5 or 6 years now.

[Circle_10]

Thanks.

How about the barrel dimensions on either an early C8 or a 1980s era 723? I got my DD lightweight CHF barrel today and it tapers from .670 down to .650 behind the gas port, .750 at the FSB point and then seems to taper gradually from about .625 down to about .580 just behind the flare at the muzzle end. Obviously the gas block is too thick to be a good fit for a 723 but aside from that how close is it to the dimensions of a Colt "pencil" barrel? The DD seems a touch heavier. Is this light enough to work for an early C8?