223 Starting Loads for 77 matchkings with CFE 223 and AR-Comp

[Munkey1973]

I have a lot of experience reloading 223 with Varget on bolt gun.

But this application is a for a 20" gas gun (1:7) with a rifle length gas block... and I have zero experience with reloading for gas guns.

Hodgdon recommends for CFE 223 A starting load of 22.5 to a max of 24.3

For AR-Comp Alliant just has on their website 22.1 ... and nothing else.
Would it be reasonable to assume that this is their starting load? ... why would they put a max load for their test rifle ?

https://www.alliantpowder.com/reloaders/powderlist.aspx?page=/reloaders/powderlist.aspx&type=1&powderid=35&cartridge=46


For both powders, I would like to try loads at 22.0 ... 22.5 ... 23.0 ... 23.5 ... 24.0.

I am not too worried about CFE at a 24.0 charge... should I be apprehensive about going up to 24.0 with AR-Comp?

 

[todbartell]

Alliant only lists max charges on their data. They also state

REDUCE RIFLE AND HANDGUN CHARGE WEIGHTS BY 10% TO ESTABLISH A STARTING LOAD.

I load 21.9grs AR Comp under Hornady's 73gr ELDm, it radars @ 2554 fps from my 16.1" barrel. This is loaded long to 2.46" OAL, which is .030" off the lands. Approx pressure is 51k psi

 

[Munkey1973]

Alliant only lists max charges on their data. They also state

I load 21.9grs AR Comp under Hornady's 73gr ELDm, it radars @ 2554 fps from my 16.1" barrel. This is loaded long to 2.46" OAL, which is .030" off the lands. Approx pressure is 51k psi

WHOA... well I must say that I am glad that I crowd sourced this question..... I would have be running pretty damn hot!

I missed that on the page before that show the tables... I would expected that they should put that on the page that has the tables as well.

So I will probably go... 19.9 ... 20.1 ... 20.9 ... 21.1 ... 21.9

My eyesight thanks you for bringing this to my attention !

 

[todbartell]

I typically run 0.2gr steps in the 223 for fine tuning, but you could get away with 0.4gr for finding pressure ceiling.

 

[old303]

A semiauto wants more of a nominal load for reliable cycling, so I could see "use THIS amount". You don't have the same range for being able to go all the way out to the minimum or maximum charges and have everything happily still work as you would with a bolt gun or revolver.