Page 24 of 52 FirstFirst ... 14222324252634 ... LastLast
Results 231 to 240 of 520

Thread: Best Suppressed SBR Ever????

  1. #231
    Join Date
    Mar 2010
    Location
    Maine
    Posts
    7,868
    Feedback Score
    0
    Quote Originally Posted by MovinMan View Post
    Now I have a brand new MPI tested bolt that has never been used. It wouldnt hurt any to pull te LMT bolt out and put it in the LMT enhanced carrier?
    Yeah, try it.

    May I ask who the MFG is on the new bolt is?
    We miss you, AC.
    We miss you, ToddG.

  2. #232
    Join Date
    May 2009
    Location
    Knoxville TN
    Posts
    87
    Feedback Score
    0
    I actually dont know who the manufacturer is, I ordered it from BCM off their site.

  3. #233
    Join Date
    May 2009
    Location
    Knoxville TN
    Posts
    87
    Feedback Score
    0
    Another thing, why ditch the spikes buffer? No good?

  4. #234
    Join Date
    May 2007
    Posts
    262
    Feedback Score
    3 (100%)
    i ran a spikes t2 in mine, ran fine

  5. #235
    Join Date
    Jun 2006
    Posts
    1,760
    Feedback Score
    7 (100%)
    I pick up my dedicated upper tomorrow. 11" Colt barrel and AAC Ranger 2 under a PRI tube. I'm going to use an A5 buffer. The standard one probably isn't heavy enough, we will see.

  6. #236
    Join Date
    Mar 2011
    Posts
    2,058
    Feedback Score
    5 (100%)
    Quote Originally Posted by C4IGrant View Post
    I wish that I could give a good answer for why the LMT Enhanced BCG's don't run in SBR's but I cannot. This is why I ONLY recommend the Enhanced CARRIER and not the Enhanced BCG.


    C4
    Quote Originally Posted by Magic_Salad0892 View Post
    Todd's right. LMT only recommends them in 14.5''16.1'' guns with CAR gas systems.

    However, it's just by chance that they work in these type of SBR.

    Also. The ST-T2 POS is a little lighter than an H2. And H2 IIRC is 4.6 oz, and a Spike's is 4.2 oz. Somebody should correct me, because I might be wrong.

    I recommend shitcanning the T2 and try your gun with H2, and a standard bolt.

    It's good to know that the BOLT shouldn't be used, and only the carrier. Thanks for being the guinea pig on that one.

    BTW: The KAC Bolt which is kind of similar to the LMT bolt, is running 100% flawless in the guns I'm using it in, and is not causing any issues. I have no idea why the LMT bolt doesn't work.

    It is my impression the BOLT CAN be used in any set up and function properly. I see no technical reason for it not to. If there is one I would be interested to hear it. I can see how the CARRIER could be trouble some for use outside of its original design purpose because of it venting more gas and having modified timing of the cam pin slot. Here is a quote from another thread that seems to have some more accurate info on the LMT enhanced Bolt, carrier and BCG as a whole.

    Quote Originally Posted by Bill Alexander View Post
    Let us perhaps be a little more precise with regard to the details of the LMT enhanced bolt and carrier system. As shown the details are very often misinterpreted.

    In the first instance one must understand why the system exists, more particulaly in the context that the design is brilliant in its execution, but as reported frequently on the errornet is not always reliable. The design basis for the assembly is specifically to enhance the durability of the M4 configuration as currently issued. This gun is to some extent unbalanced. Port pressures running military grade ammunition are well in excess of the design levels which leads to very high carrier acceleration rates (+22 f/s/s). this combined with chamber pressure drop often creates the undesirable condition that the bolt commences to unlock while still subject to a degree of head thrust from the cartridge case. The result is that the lugs are subject to a biaxial loading of both shear and bending.

    The LMT system being both the carrier and the bolt seeks to operate directly in this gun and elleviate symptoms. The carrier is set up with a longer delay during the initial portion of its movement. To facilitate this longer cam path and movement of the bolt forwards in the carrier, the front edge of the carrier is extended such that it still continues to retain the extractor pivot pin. Additional exhaust vents act to drop the piston pressure faster and to relieve any blowby at the tail of the bolt.

    The bolt itself is of particular interest. The function of the dual spring extractor is frequently misinterpreted as an attempt to add spring force to the extractor claw. Rather it reduces the fatigue that the extractor spring(s) undergo by allowing the use of longer springs with lower K values; the % relative compression during the movement of the extractor is reduced. Remember that additional extractor force is not required now that the carrier is slowing the extraction cycle. The mitigation of stress in the bolt is accomplished in several ways. Material is the least visible change but is important to the design. The traditional Carpenter 158 is abandoned, being replaced by a significantly tougher grade from a different manufacturer. The lugs themselves are generously radiused between lugs and at the rear the diameter is actually reduced to allow a larger transition radius to be machined. The incorrectly identified sand cuts on the lugs are stress relief cuts. These allow any individual lug to elastically deform and give a smoother load over the contact patch. While this type of feature is very difficult to calculate and even more difficult to implement it helps to place the lug in a true shear load rather than amplify the bending moment. As noted the lug opposite the extractor is relieved. This feature prevents the unequal transfer of load to the two opposite lugs but I would argue that the stress relief groove already in place largely accomplishes this purpose. This is a academic quibble so I will bow to LMT in this respect. There is one additional feature that can be found in the bolt, but I am not at liberty to disclose the detail.

    When considering wether to use the LMT parts one must consider the weapon. Correctly ported guns will derive little or no benefit from a carrier that is specifically set up to absorb excessive port pressures and some degree of residual case pressure. If not sufficiently gassed the reliability will suffer. This is not a fault of the carrier rather a mistake made in the application so be careful with simple substitutions. The bolt itself is exemplary. If not constrained by a $ value the bolt is a worthy addition to any rifle and will do nothing but enhance the durability of this part of the system.

    Bill Alexander

  7. #237
    Join Date
    Mar 2010
    Location
    Maine
    Posts
    7,868
    Feedback Score
    0
    Quote Originally Posted by MovinMan View Post
    Another thing, why ditch the spikes buffer? No good?
    Non standard buffer weight sucks to measure by, and the tungsten powder causes bolt bounce.

    Ryan, standard A5 buffer should work fine.
    We miss you, AC.
    We miss you, ToddG.

  8. #238
    Join Date
    Jan 2011
    Location
    Canon city Co. at the moment
    Posts
    3,076
    Feedback Score
    5 (100%)
    Tag for later
    Quote Originally Posted by Split66 View Post
    I wouldnt listen to BCMjunkie. His brown camo clashes like hell with his surroundings. His surroundings are obviously pinkish and lacey and have big hooties.

    Instagram Dangertastic
    Danger@Flickr http://www.flickr.com/photos/m41979/

  9. #239
    Join Date
    May 2006
    Location
    VA/OH
    Posts
    29,630
    Feedback Score
    33 (100%)
    Quote Originally Posted by TMS951 View Post
    It is my impression the BOLT CAN be used in any set up and function properly. I see no technical reason for it not to. If there is one I would be interested to hear it. I can see how the CARRIER could be trouble some for use outside of its original design purpose because of it venting more gas and having modified timing of the cam pin slot. Here is a quote from another thread that seems to have some more accurate info on the LMT enhanced Bolt, carrier and BCG as a whole.
    From talking with LMT, this isn't the case.

    The enhanced carrier slow down the un-lock speed and blows the extra gas out. This is VERY much needed in a suppressed weapon.

    I also have tons of expereince with making the enhanced carrier work AND seeing the enhanced bolt and enhanced BCG FAIL to form a pretty good opinion on the subject.


    C4

  10. #240
    Join Date
    Mar 2011
    Posts
    2,058
    Feedback Score
    5 (100%)
    Quote Originally Posted by C4IGrant View Post
    From talking with LMT, this isn't the case.

    The enhanced carrier slow down the un-lock speed and blows the extra gas out. This is VERY much needed in a suppressed weapon.

    I also have tons of expereince with making the enhanced carrier work AND seeing the enhanced bolt and enhanced BCG FAIL to form a pretty good opinion on the subject.


    C4
    I surely understand the reason the carrier works in a suppressed weapon. That makes sense to me. I don't doubt that.

    What I don't understand is why the enhanced bolt would not work. It is, from a technical stand point, a Superior bolt. What is the technical reason for it to hinder function in a weapon, and in what way does it hinder the function of the weapon?

    And since you do have so much experience I am interested in what problems the bolt caused that a standard one does not.

Page 24 of 52 FirstFirst ... 14222324252634 ... LastLast

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
  •