Page 2 of 2 FirstFirst 12
Results 11 to 17 of 17

Thread: BM Upgrade Suggestions

  1. #11
    Join Date
    Jun 2006
    Location
    NoVA
    Posts
    10,780
    Feedback Score
    17 (100%)
    Quote Originally Posted by Canonshooter View Post



    If this AR is to be used hard for possible self defense or at a training course I'd do the following:

    1. Better staking of gas key (I'd replace key with a BCM key and screws and stake with a MOACKS)

    2. Install mil-spec receiver extension and stake (Not needed your AR currently, Mil-Spec receiver extenstions are for CAR stocks, your Sully uses a 'entry length' rifle receiver extension which use a CAR buffer and spring)

    3. Install heavy-duty extractor spring and insert (I'd get the BCM SOPMOD upgrade kit which includes an extractor, pin, spring, buffer, Crane O-ring and gas rings or better yet replace the bolt with a BCM unit and use your Bushmaster bolt as a backup.)

    4. I am also considering the MGI Buffer - is it worth it? (I'd just use an H buffer from CMT and a standard power chrome silicon spring)

    5. Chip McCormick trigger group - any comments on this product (I've been shooting competitively for over 25 years and can make good use of a crisp trigger pull)? (McCormick trigger groups are pretty good but they have a tendency to double after awhile, for a 'social' gun I'd run a stock FCG or a Geiselle)

    Not related to reliability, but I am also having the AK Concepts FSC556 compensator installed in place of the lame "Izzy brake" that came from the factory (and not indexed perfectly straight as typical of BM QC). (If the FSC556 perm. mounted will make 16" it's a good choice it's a great brake and flash hider).
    My opinions are above in blue.
    Chief Armorer for Elite Shooting Sports in Manassas VA
    Chief Armorer for Corp Arms (FFL 07-08/SOT 02)

  2. #12
    Join Date
    Sep 2007
    Location
    New Hampshire
    Posts
    1,217
    Feedback Score
    6 (100%)
    Quote Originally Posted by gotm4 View Post
    My opinions are above in blue.
    Thanks - much appreciated!

    What is the difference between the H, H2 and H3 buffers?

    http://www.bravocompanyusa.com/AR15-Stocks-s/49.htm

  3. #13
    Join Date
    Jun 2006
    Location
    TN
    Posts
    89
    Feedback Score
    0
    Quote Originally Posted by Canonshooter View Post
    OK, thanks - that's good to know.

    The other benefit - at least according to MGI - is that the heavier buffer allows a little more time for chamber pressure to drop before extraction begins, thus decreasing some of the stress on the extractor.

    BTW, the Sully stock weighs in at 1 pound/2 ounces and is solid, not hollow like the A2 or A1 stocks. This extra weight/mass is also helpful for "recoil reduction" and eliminates all noise from the buffer tube/spring. In combination with the FSC556 brake and Sully stock, I'm thinking the MGI buffer would really tame what little muzzle jump there is and help make fast, accurate hits that much easier.

    That is true, and you can get that delayed extraction timing from any of the buffers of a similar mass. In the case of the MGI buffer, that is 7.1 ounces, which is approximately the same mass as a 9mm "B" buffer.

    The MGI RRB buffer goes on to provide an active mechanism to cancel and spread-out the recoil impulse that occurs when the moving masses of the buffer and carrier impact the back of the receiver extension(buffer tube).
    This reduces felt recoil, and also minimizes muzzle flip.

    These recoil reduction and muzzle flip improvements do not occur with simply adding mass to the buffer system. Conservation of momentum states that the same amount of energy will be transferred to the shoulder, whether you use a light fast moving buffer or a slower heavier buffer.
    You must actively do something additional to reduce these effects, and the MGI buffer has a mechanism to do that.

    Regarding buffer mass, you must balance the mass of the buffer to the gas system in the rifle. Sometimes with a new barrel, the gas port is not sufficiently large enough to drive a heavy buffer reliabily.
    So, take that into consideration when selecting buffers.

    As the gas port enlarges from erosion, then heavier buffers may come into play, to compensate for the changes in the gas system from erosion of the port.
    This is what the MGI buffer was designed to alleviate, and it(or any heavier buffer) can be inserted into the system when the gas system has a large enough port(either made that way, or from erosion) to function reliably. The active recoil-reducing mechanism in the MGI buffer "self-adjusts" to continuing erosion in the gas port to keep things under control over the life of the barrel.

  4. #14
    Join Date
    Aug 2006
    Location
    Southern California
    Posts
    1,108
    Feedback Score
    0
    Quote Originally Posted by Canonshooter View Post
    What is the difference between the H, H2 and H3 buffers?
    The weight.

    Randall Rausch
    AR15 Barrel Guru
    California Precision Rifle Club founding member

  5. #15
    Join Date
    Jun 2006
    Location
    NoVA
    Posts
    10,780
    Feedback Score
    17 (100%)
    Randall you forgot the H3, 3 tungsten weights. 5.6oz.

    Then there's the Colt X buffer (I think is 8oz)
    Chief Armorer for Elite Shooting Sports in Manassas VA
    Chief Armorer for Corp Arms (FFL 07-08/SOT 02)

  6. #16
    Join Date
    Aug 2006
    Location
    Southern California
    Posts
    1,108
    Feedback Score
    0
    Quote Originally Posted by gotm4 View Post
    Randall you forgot the H3, 3 tungsten weights. 5.6oz.

    Then there's the Colt X buffer (I think is 8oz)
    I did not have those here to take apart and photograph.

    The inside of an H3 looks amazingly similar to an H2 with the steel weight being replaced by the tungsten weight.

    I'm really interested to see what's inside the X buffer, but I'm not going to buy one just to satisfy my interest...
    Randall Rausch
    AR15 Barrel Guru
    California Precision Rifle Club founding member

  7. #17
    Join Date
    Sep 2007
    Location
    New Hampshire
    Posts
    1,217
    Feedback Score
    6 (100%)
    Great info, thanks! For my application (low round count through the barrel) the H1 buffer should fit the bill?

    If I have the resources, I may give the MGI a try...

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •