Data for 55 grain FMJBT w/ 1 in 9 twist AR15

1988z01

June 12, 2011 18:59

Hey There:

I'm looking for some load data for an AR15 with a 1 in 9 inch twist. I've got 55 grain FMJBT w/Can. bullets. I have all the typical load data, but I don't have anything specific for a rifle with a 16 inch barrel with a 1 in 9 inch twist.

Thanks

0

• 

  Hawk Carse

  June 12, 2011 19:25

  The barrel length and twist do not affect the powder charge for a given weight of bullet.

  0
• 

  dcs shooters

  June 13, 2011 06:29

  Just use the load data you have.
  The 55gr will just be a plinking load for the 1/9 twist.

  0
• 

  Mobuck

  June 13, 2011 07:14

  This not a recommendation!
  My loads using LC cases, CCI#41,Privi 55 FMJBT,and 25.5 grains of surplus 844 gives close to 3200 fps from a 24" and 2900 fps from a 16"(both 1-9 twist) measured 10' from the muzzle.
  Every rifle will be slightly different but these loads were fired through 2 of each barrel length over the Chrony. Accuracy was under 1 1/2" with 9x=adequate for the intended purpose.
  I'm confident enough in this loading to load up about 5K for future needs.

  0
• 

  Mobuck

  June 13, 2011 07:53

  Just corrected my barrel length. The 3200 fps was from a 24" 1-12 twist bolt action rifle not a 20" AR. A 20" would expected to be 1/2 way between.

  0
• 

  BUCKAWHO

  June 15, 2011 16:18

  Hi...I use both 25 gr. 748 or 22 gr. 4198 behind 55 gr. Hornady FMJBTs in my 16 in. 1/9 twist Colt. BT

  0
• 

  sandwarrior

  June 17, 2011 04:11

  5.56 or .223 chamber?
  
  You can start using .223 data for a 5.56 chamber. But, you won't be limited when you get to the top. The 5.56 runs hotter than .223. DON'T keep going up with the .223 chamber
  
  Anyhow, as you probably know, the 1-9" twist is optimized for heavier bullets. Pushing 55 gr. bullets to normal speeds of 3100-3200 is fine. The problem is bullet concentricity exacerbates accuracy problems when bullets are twisted too fast. So, you may not get the best accuracy from 55 FMJ bullets. But, 55 FMJ's aren't known for the best accuracy in .224" bullets anyways.
  
  I would just start @ 25 gr. of H4895, or IMR8208 data and work up. For dumping loads TAC, X-Terminator, Win 748, BL-C2, AA2230, H322 will all work fine starting at the given starting points and working up.
  Accuracy loads for me and lighter .224" bullets are with H4198 and AA2015. Both of those can be found on www.hodgdon.com reloading data.
  
  -good luck

  0
• 

  Mobuck

  June 17, 2011 06:56

  The 24" bolt rifle is a Wby Vanguard(Howa) stamped .223.
  The 16" is a DelTon 5.56 not chrome lined.

  0

Please sign in to leave a comment.