223 rem. improved 40° shoulder question

[bobcat93]

I'm making up some loads for fire forming a new 223 rem. Improved 40 shoulder and would like to know if anyone has experience using IMR 8280 XBR powder in this cartridge
Thank you

Here is what im using for fire form loads..I have not tried them yet.
I have a tight neck chamber .245"
Brass: Lake city brass ( I turned necks, I have an OD. loaded round .243")
Primer: Remington 7 1/2BR
Powder: IMR 8280 XBR load of 23.6 gr.
Bullet: nosler custom competition HPBT 69gr.
Well this is what I plan to use for fire forming and load development due to the fact I have 8lb. Of this powder..not sure if its the best for the above combination.. I have a lot of other powder if some one could lead me in a better direction , I'm all ears!

 

[13red56]

I use 8208 with 50-52 gr bullets to fireform in Lapua brass with great results. I shoot the 69's in my gun but I haven't ever used 8208 under them. It seems I get better accuracy and ES numbers when I get around the max load for the 223 when fire forming.

 

[40X Guy]

You will be fine with your fireforming load. My sons .223AI with Lapua brass in a no turn .252 neck chamber throated for 75 A-Max uses 24.5 grains of 8208 powder with CCI BR-4 primers. His rifle is scary accurate and does not matter what powder you use in it close to 8208's burn rate. Primers did make a difference, I started with Fed. 205 GM and could not get that extra small group but a change to BR-4's really woke it up.

The .223AI caliber will make you smile!


Frank

 

[amlevin]

The .223AI caliber will make you smile!


Frank

Out of curiosity, how does the .223AI cartridge feed from a magazine in an AR? Does the 40 degree shoulder slide past all the obstacles as well as the standard case?

 

[lpreddick]

i have one as a bolt gun and it is a ghog killer, BUT it fed lousy from the magazine. i finally converted to a single shot using an aluminum follower and it chambers 90%of the time. 8208 XBR with 52 fowlers is perfect.

 

[40X Guy]

Amlevin, I have no idea if .223AI cases feed out of AR mags, but sounds like fun...

Frank

 

[Link]

I am under the understanding that the idea of the AI is it will hold more powder.
Is the upper node always in that more powder range or is it sometimes in the standard load range? If so is all the improvements [ chamber, fireform etc] for nothing or does the 40* neck improve on barrel life?

thanks Link

 

[fredhorace77]

i dont really worry about nodes with mine. i just find a somewhat accurate load at 100yrds. and go hunting. never really take shots past 250 yards so i could care less what node its on or off. not having to trim the brass as often is one benefit. besides, having the "A.I." at the end is just "cooler". lol

 

[jpretle]

"Out of curiosity, how does the .223AI cartridge feed from a magazine in an AR? Does the 40 degree shoulder slide past all the obstacles as well as the standard case?"

No problems feeding the AI in an AR-15. I've done many thousands, in rapid fire strings, w/o a hitch.

 

[flatlander]

I never did an AI in the AR15, but a couple of friends that I shoot HP with did - one had no issues with feeding, the other had all sorts of problems. Not sure it wasn't a magazine-related problem, but we tried a bunch of different mags in his rifle, and he still had some problems.

I use AICS 10rd polymer mags in my bolt rifle chambered for the 223 AI, and have no problems getting them to feed in it.