Load data AR-Comp behind 55g 223 16" barrel

[DIYguy]

Did a search but didn't find the right data.

Been using AR-Comp for my match loads behind Hornady 75g BTHP 223 on the single stage, spent a LOT of time doing the ladder workup, etc.Running those through an 18" Super Match barrel for 100 yards load. Looking to start loading 55g on the Dillon 650 for use in my 16" gun at the 25 yard range. All the load data is based on 24" barrel using 25.6g.

Would prefer to start with a load that is pretty close to correct without having to go through all the trial and error test loads to get there.

Anyone using AR-Comp for 55g 223 out of a 16" barrel and what are you loading?

[AHI]

explain correct 

[DIYguy]

Good point.

I did six chrono test with ten rounds per test of factory ammo, Norma Tac 55g, at 74 degrees. All the test came in pretty consistent at an average between 2,940 and 2,950. The factory ammo was grouping with four out of five rounds touching inside the 1" bullseye. 3x Vortex Spitfire optic.

Correct load looks to be about 2,945 fps out of a 16" barrel. Published load data keeps saying in the 3,350 fps range but those are using 24" barrel so doesn't help.

How many grains of AR-Comp behind a 55g Hornady bullet will result in 2,945 fps out of a 16" barrel.

Individual results may vary

[DIYguy]

Correction:

Did four test of (10) rounds each, (40) rounds total

Average low :    2,889.7

Average high:    2,975.5

Overall average:    2,934.7  fps

 

Edited August 13, 2019 by DIYguy

[DIYguy]

The initial test I did were using Norma USA ammo. Further test showed the Norma is about 80 to 100 FPS +/- faster than another brand I tested.

For reference I've attached a spread sheet template I use for every load and firearm when working up load comparison. 2nd page show the load work-up for different load weights. The spread sheet is used along with test targets to compare load and grouping.

20190903085200565.pdf Reloading Recipes-Rifle (DPMS 223) 9-03-19.pdf