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Thread: M4 Feedramps

  1. #21
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    Quote Originally Posted by gotm4
    Rifle = 45 degrees
    M4 = 52 degrees
    I took some specific measurements on ramp angle a while back and came up with 37-38 degrees on rifle ramps and 45 degrees on M4 ramps.

    Depending on which side you were measuring from, we may both be right...

    Here's how I was measuring:

    Randall Rausch
    AR15 Barrel Guru

  2. #22
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    I read it in 'The Black Rifle II' page 69-70 (Designing the New M4 Receiver), they credited the data from Copyright 2002-2003 Colt Archive Properties LLC Used w/permission, all rights reserved. I'm sure the angles vary slightly from manufacturer to manufacturer. Colt also may have since changed angles I'm not sure. I've never checked one myself.
    Chief Armorer for Elite Shooting Sports in Manassas VA
    Chief Armorer for Corp Arms (FFL 07-08/SOT 02)

  3. #23
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    Great Post !

    Thanks for taking the time to put it together.

  4. #24
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    I've always subscribed to the belief that M4 ramps probably don't help much, but don't hurt anything either... But I have a "frankengun" carbine that has an M4 ramped barrel extension and no ramps on the receiver. Shot maybe 1000-1500rds through it with at least 2-3 times every 100 rds where a bullet tip would hang up on the upper receiver just short of the barrel extension, causing me to get a little extra practice with transitions and the "rack and roll" drill.

    After seeing some pics c4igrant posted here of Rock River's dremel jobs, I thought "hell, I can do better than that" and gave it a shot.

    Roughly 500 rds since my dremel job, I've had zero function problems. So maybe those M4 ramps do help a little. They sure seem to have helped in my beater carbine.

  5. #25
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    Quote Originally Posted by K.L. Davis View Post
    the M4 style ramps are cut so that the cut "breaks through" the barrel extension and cuts slightly into the upper receiver.
    Man this site it awesome, About 2 months ago when I really got intrigued and started to research my first AR purchase and I started narrowing it down to an M4gery...lol...
    I asked almost 5-6 guys that sounded like they had a handle on what they were talking about in two different shops, One was a salesman who was pushing the S&W M&P AR to me and he didn't have a clue.

    Thanks again M4carbine...

  6. #26
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    bump...

  7. #27
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    It seems that the M4 feed problem is related to a fast moving bolt and a slow moving magazine. It would stand to reason that long heavy grain ammo would also add to this problem.

    Would a mid length gas system help here? I am beginning to believe that the 16" mid-length system may be the best of all possible worlds.

    With all of the hype on 'M4 cuts' I wonder if we will see regular uppers selling at a discount.

  8. #28
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    This is some of the best M4 info I have read in a very long time. Thanks.
    In no way do I make any money from anyone related to the firearms industry.


    "I have never heard anyone say after a firefight that I wish that I had not taken so much ammo.", ME

    "Texas can make it without the United States, but the United States can't make it without Texas !", General Sam Houston

  9. #29
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    Quote Originally Posted by C4IGrant View Post
    I shoot 77gr ammo in a weapon with rifle feedramps. No issues.


    C4
    I also shoot, 75gr, 77gr and 80gr, HP and match grade ammo with a rifle feedramp configuration. Absolutely zero issues.
    From there to here,
    from here to there,
    funny things
    are everywhere.

  10. #30
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    That was a very informative and descriptive post. When I worked as a civilian armorer with the Marines and we converted some M16A4's to M4 configuration we did a complete mod to include the receivers. That was the way they directed it to be done.

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