ar15 barrel in 6mm or 22 grendel

Discussion in 'Gunsmithing' started by ajhardle, Dec 31, 2013.

  1. ajhardle

    ajhardle Well-Known Member

    Jun 21, 2012
    It's time for a new barrel. I was looking for the perfect 6mm chamber ( light recoil and long barrel ) for my Savage when i came to the conclusion that the 6mm grendel was the right size, so why not modify the AR.

    Before you ask why 6mm, not 6.5 grendel, let me explain. Most grendels shoot something like a 123 gr with a g7b.c. ~.26. People say anything with a higher b.c. takes away from case capacity. A 6mm in the 105 range is going to have a higher b.c. and the Berger 95vld is short enough to avoid the doughnut, while being light enough, the extra velocity should make up for the reduced b.c. at 600 yards.

    Well if a 105 going 2700 is to going be better than the 6.5 123 at 2600fps, maybe a Berger .224 90vld with a similar b.c. going faster will be even better. Same length as the other bullets.

    Questions: 1. Has anyone used these calibers?

    2. What velocities can be expected?

    3. And can I give a gunsmith a dummy round at mag length to make a throat that will allow the bullet to seat at the lands, with the hope that near max length is right at the lands?
  2. airborneike

    airborneike Active Member

    Mar 27, 2011
    Short answer is yes yes and yes....Most call it a 6ar because of the grendel trademark.

    go to

    excellent performer for the reasons you stated and more.

    set up a dummy round and send it to PTG and they will make you a reamer.

    Happy new year


  3. Trickymissfit

    Trickymissfit Well-Known Member

    Jun 11, 2010
    back in the 1970's the Army played around with a 5.56 necked up to 6mm using an 85 grain bullet. They said they were getting close to 2900 fps. The bullets used in the testing were all from Hornaday (just generic hunting bullets). They were said to have 7.62x51 ballistics from an M16. Carter killed the project when he became President. The project looked like a winner all the way around, and had quite a bit more power than the standard 5.56 using 53 grain bullets. The main goal was to be able to bust thru the magazine chest pack that folks using an AK 47 had. From what I hear it would do it at 250 yards.