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XM193; Poor Google fu

  1. I spent some time checking the Algore-web trying to find concrete info on XM193, and if it really is a hotter load than M193. I found one reference that said that XM193 is really M193 that the military rejected.

    I'm interested because this is what I keep in my 16", 1/9 twist M&P15T, and I'd like to know if this is the best FMJ round given my barrel length and twist. I also read that with the 55 gr. M/XM193 rounds, the twist rate really isn't that important, it's only when heavier bullets are used that the twist rate becomes important.

    I did find some good info discussing fragmentation of M193, and that velocities need to be above 2700 fps for fragmentation to realiably occur.
    From what I read, XM193 does about 3075 fps. from a 16" barrel, and keeps above 2700 fps out to about 150-200 yards.

    So my questions are:

    -Is X/M193 (55 gr.) the proper bullet weight ammo for my rifle (vrs. heavier 62 & 77 gr. rounds) given the twist rate and barrel length of my rifle?
    -What is the real difference between XM193 and M193 ammo?
    -Does barrel twist rate effect velocity to an appreciable degree?

    I hunted for answers to these questions before I posted this, but my google-fu was weak today!:rofl:
  2. Optimal twist/weight is:

    1/9 - 55gr - M193
    1/7 - 62gr - M855

    77gr (MK 262 MOD 0/1) will not stabilize, and will most likely keyhole from a 1/9.

    XM193 didn't meet contract specs and it's better to recoup some cost and sell it off than throw it away or remanufacture. I think someone's told you a tale...

  3. Winchester White Box is M193 for all practical purposes, works great in a 9 twist and available at Wally World cheap.

    Some times I run across the Malayisian M193, it's pretty good surplus and hits the required velocity from a 20"
    IMO the M193 55gr FMJ will have better terminal effects than M855 from a shorter barrel weapon.
  4. as stated, XM193 is MIL contract ammo that did not meet final MIL inspection [for whatever reason], hence the X designator.

    I have a 1/7 twist and a 1/9. The M193 does shoot better in the 1/9 and my M855 [contract ammo] shoots better in the 1/7....marginally.

    Inside of the ranges I shoot at [generally <200m] I am still able to take care of my target quite well regardless of the ammo I use in either twist rate.