Thread: Anyone played with 223AI?

Originally Posted by kiwi303

at least with a 223 factory ammo is reasonable and it would be quite usable with forming loads. 223 is cheap to run and I reckon Youd loose that with 204

I'll be in touch @Jaco if i do want to scratch the itch

Greetings @kiwi303 and all,
First my apologies for having, along with others, hijacked your thread. Parker Ackley came out with his series of improved cases in the 1940's and 50's. The idea was to get a bit more velocity from the limited number of standard cases available at the time. Large increases in velocity were claimed due to the case shoulder shape but little of the data was chronographed let alone pressure tested. Much more recently actual pressure testing has dispelled some of the myth. The only cartridge I can think of that has been adopted as a factory cartridge is the .280 Remington AI. Hodgdon publishes pressure tested data for both the standard and AI versions. The AI version is loaded to a higher pressure and charge, velocity and pressure are all linear (form a straight line when plotted on a graph. A little number crunching indicated that the increase in velocity was around 35 fps for the AI over the standard version, not the several hundred fps claimed by some.
If you really like the look of the 40 degree shoulder then by all means go ahead but there is another path. The .223 is most commonly chambered in semi autos in the US and these have particular requirements regarding port pressure and it appears to me that current data has been dialled back for some powders due to this. Of the powders I have worked with AR2206H (H4895) seems to give decent velocity within published data where some later data for other powders struggle.
Best of luck and regards Grandpamac.