AR-Comp Loading questions.

[bryanbag]

I am getting into loading rifle, (been loading pistol for a couple years now)
Well anyway. The only powder I have been able to get my hand on is the Alliant AR-Comp powder. Since neither one of my reloading manuals have anything on this powder, I went to Alliant website.
Now they list a couple different bullet weight and what charges they used. Ok good starting point.
He is where I run into another problem. Projectiles - The only ones I have been able to put my hands on is the Sierra Varminter 63gr SMP.

I sent Alliant an email stating the issue I was having and if they could shed some light on this.
The email I received back from Alliant. They told me was to take the bullet and powder weight and split it down the middle then reduce by 10% and work up from there if need be.

This scared me a little. My question is. Is this a common practice when using odd weight bullets?
I did this anyway. Here is what I came up with.


What Alliant had listed on there site.
55g HPBT - 25.6gr
68g HPBT - 23.5gr
The split in powder weight is 2.2gr's. Split the 2.2 in half and get 1.1gr's
The split in bullet weight is 13g. So 61g bullet is in the middle.

So with a little math, I came up with
61g bullet with 24.5gr's of AR-Comp.
From there with a little more math I was able to come up with powder weight for each bullet,
from there I reduced by 10%, thus giving me 22.5gr's of AR-Comp to start with.
With the extra math I was able to get powder weight for the 63g bullet I have.
What I came up with for the 63g bullet is 24.2gr's of AR-Comp.
I reduced this by 10%, this gave me a starting load of 21.78. I round down to 21.5 to start.

I did make up a couple round of ammo. I load 10rd's with 21.5gr, next load was 10rd's with 22.8gr, Next was 10rd's with 23.0gr and 23.5gr.

Am I on the right track here?
Rifle info - Daniel Defense M4 with a 18'' 1n7 twist barrel.
All LC brass. Bullet OAL is 2.260
Primer - CCI SRP #400

Has anybody worked any load using this powder? If so what bullet and weight and charge weight?

I sure hope you all can make out what I'm trying to say. If not let me know and I will do what I can to better explain.


Thanks
Bryan

[markm]

Am I on the right track here?


I think so. Pay attention to the total package. How the rifle cycles, how far and where the brass is coming out, etc.

Ideally you'll want to combine this with Chronograph data too.

[bryanbag]

I think so. Pay attention to the total package. How the rifle cycles, how far and where the brass is coming out, etc.

Ideally you'll want to combine this with Chronograph data too.

Thanks for the info. I planed on doing this anyway.
I do not have access to a chrono at this time and don't know anyone that has one.
So I will have to go off feel, Rifle cycling, where and how far brass is being discharged and pressure signs. Hopefully I will be able to get one later on this year.

[308sako]

This powder has given me excellent results in several AR's. I predominately shoot 55 grain bullets with it and have found 25.2 grains to be a stout load.

I also find interpolation necessary at times, but would add caution to that approach. Additionally I think the initial intervals you have chosen are too large for safety. And the 10 rounds more than necessary to feel your way. Guess it's a matter of style, and what you are trying to accomplish with your reloads.

Be sure to report back with your success!

[bryanbag]

This powder has given me excellent results in several AR's. I predominately shoot 55 grain bullets with it and have found 25.2 grains to be a stout load.

I also find interpolation necessary at times, but would add caution to that approach. Additionally I think the initial intervals you have chosen are too large for safety. And the 10 rounds more than necessary to feel your way. Guess it's a matter of style, and what you are trying to accomplish with your reloads.

Be sure to report back with your success!


So you think .5g is to much of a split between test loads?, I did think about going .2g or.3g between test loads, but decided with the .5g split.
One of the main reason I went with .5g split is- being in New Orleans rifle ranges are not very close to me (min 1hr drive) and bring 5 to 10rds of each powder charge. Ruffle 30 to 70 test rds. Test time to drive time and gas doesn't work out to well.
Over the past 2 or 3 month I have been do as much research on this powder as I can.
AR-Comp is a more temp insensitive version of RL-15. The load data overlaps, but is NOT interchangeable. So looking at RL-15 data compared to AR-COMP data (what little I have found) and talking with local reloader's and on different reloading forums.
Weighing the pro's and con's at least for me. I believe .5g split between test load is acceptable.

As with anything, there are different ways of looking at things. Everybody has there own views. I try to look at as many different angles and think about the pro's and con's.
I usually don't jump more than 0.5 gr at the most (22.0, 22.5, 23.0, 23.5, 24.0) I don't load more than 5 to 10 per charge, since I'm really just looking for pressure signs and ballpark velocity. Once I knew I could approach a charge range safely I'd narrow the range down and load 5 to 10 in 0.3 gr increments (for example 22.7,23.0,23.3,23.6).


With components being in high demand, yea things are starting to catch up with demand (some what) but funds also play a big part on what and when I can get supply's.
I am getting what I can. AR-COMP and the 63gr Sierra SMP have been the only thing I have been able to put my hands on. So I got to work with what I have been able to get.


Thank you for the info.
Bryan

[308sako]

Been loading for 49 years, a lot more in the last 35. What I have found to be true is that using about 1% change in intervals saves time and money in the long run when building a new load. That means about 1/4 grain for the 5.56, and about a 1/2 grain for the .308 and close to 3/4 grain for the 300 Magnums.

I hope this discussion helps you reach your goals.

I strongly recommend the acquisition of a good chronograph.

Once I am close I then work as small as 1/10 th of a grain even in the .308. You can see the difference in accuracy with a good rifle as shown below. Some old work with Varget in a .308 bolt rifle. A repeatable node was found at 47.7 grains with a 155 grain bullet in light Winchester brass with CCi BR primers.

Note these groups were fired at 300 yards.

http://i181.photobucket.com/albums/x160/308sako/DSCN0023-1.jpg


http://i181.photobucket.com/albums/x160/308sako/DSCN0024-1.jpg

[bryanbag]

Thank you so much for the info. I will defiantly use this in the future.
I knew it only took small amounts powder to make a difference in how a bullet would preform, but damn .1g makes a big difference.

Yes, I need to invest in a chrono. Going off group size and feel isn't really the best way to develop good loads.

Thanks again.
Bryan

[ennbeegunny15]

This powder has given me excellent results in several AR's. I predominately shoot 55 grain bullets with it and have found 25.2 grains to be a stout load.

I also find interpolation necessary at times, but would add caution to that approach. Additionally I think the initial intervals you have chosen are too large for safety. And the 10 rounds more than necessary to feel your way. Guess it's a matter of style, and what you are trying to accomplish with your reloads.

Be sure to report back with your success!

Thanks for the info, I hate the fact that we have jump around and pick up whatever is available, but it has allowed me to do some load development and that in itself has been a learning experience.

[WC 2-3]

Wish I could find some AR Comp. it's what I use in my 77 gr loads. 22 grains shoots about .75 MOA for me.

[308sako]

Wish I could find some AR Comp. it's what I use in my 77 gr loads. 22 grains shoots about .75 MOA for me.


I wish I could find 32 lbs of it, for the coming two years...

[bryanbag]

Any and all site that you can select NOTIFY WHEN AVAILABLE, do it. That's how I was able to get my powder.


Sent from the ultimate iPhone 6s while sitting on the pot!!!