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About AR feed ramps

Discussion in 'Rifle Country' started by D.B. Cooper, Oct 23, 2016.

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  1. D.B. Cooper

    D.B. Cooper Member

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    Okay, now I have to ask about feed ramps.

    I'm researching barrels for what will be my first AR. (Many of you have already offered a lot of help in my twist rate question and thanks.)

    I keep seeing that all of these 20" A2 barrels have "M4 Feed ramps," and those feed ramps were modified to increase reliability on the shorter barrels. I've also read that the M4 upper receivers have a matching profile.

    Of course, I'm trying to build an A2 rifle. (I never do "easy," "common," or "simple.")

    Can I just put one of these A2 barrels with M4 feed ramp onto an A2 upper receiver, or do I need to be searching for a 20" barrel with an A2 feed ramp? (Which I probably won't find-A2 anything is hard to find.)
     
  2. LoonWulf
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    LoonWulf Contributing Member

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  3. 243winxb

    243winxb Member

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  4. Derek Zeanah

    Derek Zeanah System Administrator Staff Member

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  5. 243winxb

    243winxb Member

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    Thats it . Ty
     
  6. Derek Zeanah

    Derek Zeanah System Administrator Staff Member

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    I copied the URL of the link in question, then here I clicked the insert photo button (to the right of the smiley face) and pasted it in.

    That's it.
     
  7. D.B. Cooper

    D.B. Cooper Member

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    Those photos help me visualize what is being discussed. Thanks. So...everything I'm seeing online says M4 feed ramp, so I assume M4 extension, but it's going on an A2 rifle receiver (Anderson lower), which is marked "OK" on the photos.

    Do A2 feed ramp barrels/extension just no longer exist? Should I just accept this, buy a barrel, and move on? or.....????
     
  8. 243winxb

    243winxb Member

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    It gets confusing with so many different manufacturers of AR's. I remembered the photo/post from when i wanted to know what an M4 was. Sorry that i dont have more info .
     
  9. LoonWulf
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    LoonWulf Contributing Member

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    with a needle file, or properly sized rat tail, id assume you could blend rifle extensions to m4 feed ramps pretty easily? I had to blend the extension on my .458 a bit to get blunt bullets to feed, that wasnt hard.
     
  10. Varminterror

    Varminterror Member

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    Pretty rare to find non-M4 uppers or barrel extensions any more.

    The lower doesn't matter at all - the feed ramps are cut in to the barrel extension and the upper - the lower is not a part of that equation.

    M4 barrel extensions and Rifle uppers work fine together - but the BEST answer in that case, instead of running with the mixed ramp "OK" condition is to simply hog out M4 cuts into your receiver. It's aluminum, it cuts incredibly easily.

    If you're ordering a custom barrel, you can get any extension you want. Brownells & Midway show in stock for the DPMS A2 stripped uppers, which shouldn't have M4 cuts. I've ordered one in the past which did have M4's.

    I use M4 cuts on all of my rifles for the improved feeding. When I get an upper without cuts, I cut them. Problem solved.
     
  11. MachIVshooter

    MachIVshooter Member

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    That's pretty much the case.

    There's also no practical reason to opt for A2 feed ramps over M4. Only if you care about a technically accurate copy of the M16A2 upper.

    I built my A2 with a LW barrel that has M4 ramps, because it would have been stupid to spend more money for a heavier barrel with crappier ramps. Only the most curmudgeonly purists would ever notice or care.
     
  12. Varminterror

    Varminterror Member

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    Barrel length has nothing to do with feeding reliability - the barrel isn't touching anything until the tip has already passed the feed ramp.

    M4 ramps cast a wider net, so to speak, to catch more bullet profiles and more COAL's more reliably. Absolutely nothing to do with barrel length.
     
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