AR 15 upper question

RowdyRawhide

New member
What value do M4 feed ramps add to a reciever and do they require any other special parts (i.e. bolt carrier group, barrel, forward assist). Thanks in advance.
 
As long as you have the barrel to match your M4 feed ramp equipped upper you are GTG. No other special parts. They are considered an advantage in carbine length rifles or M4s and when using the longer heavy bullets. If I remember right, something about the carbine length gas system makes the bullet feed with the bullet tipped down a little lower. I've had carbine length ARs for years without M4 ramps and never had a problem. Many feel they are unnecessary unless your weapon is full auto capable.

They are all the rage now and certainly don't have any cons that I know of. I get them on all my M4s and carbines these days... just because.
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The only reason I ask is because I am going to start an AR build here before too long, and need to know if there certain barrels that are required or if they just use standard barrels. Maybe a dumb question but I just don't know anything about the finite things on AR's, which is one of the reasons for the build. I may not go that route, but I need to know beforehand.
 
Originally Posted By: yotedog65284The indexing coller is what has the feed ramps cut in it. I know bushmaster and CMMG use them.

Actually, the barrel extension is either an "M-4" extension or it's an "AR-15" extension. They both have feed-ramps made into the barrel extension. The M-4 feed-ramps are just cut at a steeper angle, and go deeper.

The receivers are a different story. They either have M-4 feed-ramps cut into them, or they don't. It won't cause you any problems to use an M-4 barrel extension on a receiver that does not have the M-4 ramps cut into it, BUT, if you have a receiver with the M-4 ramps cut into it, you will be unhappy if your barrel extension is not cut with the M-4 ramps. If you had a situation like this, the tip of the bullet would, or at least could, run up the ramp on the receiver, and then would hit the lip on the barrel extension. This would at the least damage the tip of the bullet. More likely it would cause you function problems.

I haven't seen an AR-15 barrel extension around for some time. Everything that I have in the shop is M-4. I think most manufacturers just dropped the other extension and only use the M-4 ones now.
 
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That is a great reference Curt, Thanks alot. Another dumb question. If an upper or barrel is marked M4 does that designate the "feed ramps", or not necessarily?

Thanks Again
Aaron


PS you guys are great and patient as well, as I am sure you get asked the same questions repeatedly, including probably this one.
 
No problem at all Rowdy. We are glad to help.

Quote:If an upper or barrel is marked M4 does that designate the "feed ramps", or not necessarily?


To make certain, you might ask Mike. All the M4s I have put together are ramped barrel ext. and receiver but I believe you can also get them without. I'm not sure if the non-ramped are marked M4 too. I think you can have the M4 barrel contour with/without the feed ramps.

Good hunting
 
Originally Posted By: RowdyRawhideThat is a great reference Curt, Thanks alot. Another dumb question. If an upper or barrel is marked M4 does that designate the "feed ramps", or not necessarily?

Thanks Again
Aaron

Some manufacturers put it on their M4 contour barrels. So it does not neccisarily mean it has M4 feedramps.
 
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