Adding M4 feedramps to A1/C7 upper

[Circle_10]

I've been thinking about doing sort of an "Early Diemaco C8 carbine" clone build with a C7 style upper receiver. I was planning on using a Daniel Defense 14.5 pencil barrel, because like the C8 they are CHF, lightweight profile, and .750 at the FSB (And also because quality carbine pencil barrels with .625 gas blocks seem to be in short supply...or else I'd just build a 723 clone....) . However the DD 14.5 are ideally meant to mate up with M4 style upper receiver feedramps. While this gun is a more of novelty build than a "serious use" AR, I intend to use good parts and want it to run as well as my other ARs. So I'm thinking I ought to have M4 ramps in the gun because based on what I've read: Rifle receiver+M4 barrel = "OK" but not ideal.
Can anyone suggest someone who can add correct M4 style feedramps to an A1 upper and then properly re-anodize the ramps? Any ideas how much the whole process might cost? There's no way in hell I'm going to even attempt to do this myself.

[Renegade04]

I've been thinking about doing sort of an "Early Diemaco C8 carbine" clone build with a C7 style upper receiver. I was planning on using a Daniel Defense 14.5 pencil barrel, because like the C8 they are CHF, lightweight profile, and .750 at the FSB (And also because quality carbine pencil barrels with .625 gas blocks seem to be in short supply...or else I'd just build a 723 clone....) . However the DD 14.5 are ideally meant to mate up with M4 style upper receiver feedramps. While this gun is a more of novelty build than a "serious use" AR, I intend to use good parts and want it to run as well as my other ARs. So I'm thinking I ought to have M4 ramps in the gun because based on what I've read: Rifle receiver+M4 barrel = "OK" but not ideal.
Can anyone suggest someone who can add correct M4 style feedramps to an A1 upper and then properly re-anodize the ramps? Any ideas how much the whole process might cost? There's no way in hell I'm going to even attempt to do this myself.

Here is something that will help you.



I will attest that a rifle upper and a barrel with the M4 feedramps works just fine. No need to alter the upper.

[Circle_10]

I've seen that pic, it is a good reference. I think my question would be why rifle receiver+M4 barrel is just "ok" rather than "good", unless the point is that in a carbine-gas gun M4 ramps are just considered an improvement over no ramps period rather than there being some particular shortcoming with the rifle receiver+M4 barrel combo itself.

I will attest that a rifle upper and a barrel with the M4 feedramps works just fine. No need to alter the upper.

That's good to hear.

[Renegade04]

I've seen that pic, it is a good reference. I think my question would be why rifle receiver+M4 barrel is just "ok" rather than "good", unless the point is that in a carbine-gas gun M4 ramps are just considered an improvement over no ramps period rather than there being some particular shortcoming with the rifle receiver+M4 barrel combo itself.



That's good to hear.

You have to realize that several upper receivers (A2) with no feedramps were outfitted with newer barrels with M4 feedramps on the barrel extension. There were some carbine uppers that were built using re-purposed A2 rifle upper receivers. Additionally, there were some C7 and A2 uppers that had slightly cut ramps to match up with the barrels with extended carbine feedramps (not to be confused with M4 feedramps). This was done in the mid-late 1980s. It was not until later on that the flat-top receivers started getting feedramps to match the M4 feedramps on the barrel extensions. This is why you can use a barrel with an extension with M4 feedramps with a receiver that does not have feedramps, but you cannot use a receiver with M4 feedramps with a barrel with an extension with rifle feedramps.

I have a 723 build (w/ C7 upper) and a 727 build (A2 upper) that use 14.5" Colt M4 barrels. They both function very well with no feed or extraction issues.

[Circle_10]

That's interesting. I had just assumed that the "M4" ramps on the barrel extension and those in the upper were developed and put into production concurrently and that factory guns would always have both. Nice builds too!

[mack7.62]

I would only add the feed ramps to the receiver if I had feeding issues, which you should not have.

[the_1iviper]

I would only add the feed ramps to the receiver if I had feeding issues, which you should not have.

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or you could source out a colt c7 upper , it should have ramps cut into it already.

[Renegade04]

/\ this

or you could source out a colt c7 upper , it should have ramps cut into it already.

Some C7 (A1E1) uppers did not have feedramps.

[the_1iviper]

C7 (A1E1) uppers did not have feedramps.

colt A1E1 733 uppers didn't have extended carbine feedramps ?

[Renegade04]

colt A1E1 733 uppers didn't have extended carbine feedramps ?

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.