Page 2 of 2 FirstFirst 12
Results 11 to 15 of 15

Thread: MK262 and maintenance

  1. #11
    Join Date
    Oct 2017
    Location
    USA
    Posts
    512
    Feedback Score
    2 (100%)
    Quote Originally Posted by Inkslinger View Post
    The muzzle velocity of Mk262 is less than M193 so wouldn’t that result in a slightly longer barrel life?
    In my opinion

    Velocity is a factor, but so is powder burn rate and characteristics among other things. A faster bullet with slower powder might erode throat at a lesser rate than a slower bullet with faster powder.
    OP, if it is factory ammo I wouldn't worry about it. If it is handloads, just keep your loads in spec and don't worry about it.

  2. #12
    Join Date
    Oct 2017
    Location
    USA
    Posts
    512
    Feedback Score
    2 (100%)
    Quote Originally Posted by mgrs View Post
    Yes, but as mentioned above probably not enough to matter. Lubrication, firing schedule, gas system tuning, and suppression probably affect it just as much if not more.

    Looking at my guns with a bore scope, the douglas 18" spr barrel ( 110 rounds, almost all suppressed, all 77gr heavy reloads) even under slow fire is taking more of a beating to the gas port than expected:


    This is a LaRue 16" lightweight barrel with 1400 rounds (much faster fire, 99% .223 pressure reloads) is doing better even though the port is 2" closer:


    Maybe not the most instructive comparison, as I do not know what LaRue's barrel steel is.
    Thanks for sharing. Noob question but are those barrels made of the same material?

  3. #13
    Join Date
    Nov 2010
    Location
    Midwest
    Posts
    4,618
    Feedback Score
    19 (100%)
    Quote Originally Posted by 5.56 Bonded SP View Post
    Thanks for sharing. Noob question but are those barrels made of the same material?
    The Douglas barrel would likely be 416R (barrel-rated stainless steel) and LaRue calls their mystery alloy "Rearden Steel." As far as I know LaRue doesn't say exactly what alloy it is, but it's a fair guess that it's a stainless alloy that's a little stronger than 416R, such as 410, 17-4PH, or some custom alloy like those. In short, they are probably not the exact same material, but we don't know for sure. It would not be radically different because there are no radically different stainless steels that would be suitable for a barrel and not cost far more than what LaRue charges for the barrel (which isn't cheap, but isn't cobalt-superalloy expensive either). The borescope photos certainly suggest it has greater resistance to heat erosion.

  4. #14
    Join Date
    Oct 2017
    Location
    USA
    Posts
    512
    Feedback Score
    2 (100%)
    Quote Originally Posted by SomeOtherGuy View Post
    The Douglas barrel would likely be 416R (barrel-rated stainless steel) and LaRue calls their mystery alloy "Rearden Steel." As far as I know LaRue doesn't say exactly what alloy it is, but it's a fair guess that it's a stainless alloy that's a little stronger than 416R, such as 410, 17-4PH, or some custom alloy like those. In short, they are probably not the exact same material, but we don't know for sure. It would not be radically different because there are no radically different stainless steels that would be suitable for a barrel and not cost far more than what LaRue charges for the barrel (which isn't cheap, but isn't cobalt-superalloy expensive either). The borescope photos certainly suggest it has greater resistance to heat erosion.
    Interesting. Thank you for the informative reply.

  5. #15
    Join Date
    Aug 2014
    Posts
    89
    Feedback Score
    6 (100%)
    Quote Originally Posted by 5.56 Bonded SP View Post
    Thanks for sharing. Noob question but are those barrels made of the same material?
    I realize there is a typo in my post- the douglas as 1100 rounds, not 110. Will edit.

    I doubt it. The douglas is confirmed to be 416 SS whereas LaRue does not share what steel is used. It is stamped "Rearden Steel" in a nod to Atlas Shrugged and is one of LaRue's in-house barrels. I would have thought they are a less expensive material like 416 as it is common for cheap, accurate barrels, but it is wearing more like a nitrided barrel. I think nitrided or not could be confirmed by testing surface hardness, but I am not equipped to do that. The throat also seems to be eroding slower. Combined with the very deep grooves and sharp lands in the LaRue, I bet it would have a very long useful service life.

    Another interesting observation, the LaRue tube pictured has a visible bur where the port was drilled, but still shoots very well for the first couple groups until it heats up. I would not expect a predatar barrel to not open up as it gets hot.

    Neither of these have been abused although the LaRue has been allowed to get much hotter. They're both longer barrels though, SBR barrels seem to suffer worse than most anything else.

    EDIT: Someotherguy beat me to it on the steel guesses.
    Last edited by mgrs; 10-12-17 at 22:11.

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
  •