.222 RMAI (Rem Mag Ackley Improved) in a 16” Contender!

[slipknot]

Does anyone have any data on reloading the .223Rem Mag Ackley Imp, in a 16" contender, with 50&55gr bullets? Mike Bellm brilliantly fixed a poorly chambered 223 bbl with this solution, but the data is scarce, to only a few loads he used to push 50's to 3000 fps in 16".
There's lots if 223AI data , but almost nothing for the RMAI ….which should be if greater interest, due to the greater case capacity and that LONGER neck!
I came across Varget data ', that was OK with compressed loads, that puts hornady V-Max's into 1 hole @100, but would like more choices. Thanks.
OS: you can Google the Bellm website to get his development and early load data.

 

[just_jon]

I load for a bunch of AIs and generally start with max loads of the parent cartridge and work up until I find pressure. IMR 8208 XBR has been my long time go-to powder for 22-250AI and believe would work well in your application. Hodgdon BL-C(2) would be another contender.

 

[QuietTexan]

the .223Rem Mag Ackley Imp,

222 Rem Mag or 223 Rem is the parent case? Sounds like 222 Rem Mag, from how you talk about the neck. Use data for the straight 222 Rem Mag data as a starting point, form the cases once, then do a pressure ladder to find the top.

H-322 is the Hodgdon Extreme powder to try IMO. I use H380 in 6x45 (6mm-223 Rem), it seems to work well. Old standard varmint powder. Hodgon has 222RM load data for both in light bullets. It's not listed in the Hodgdon data but Benchmark would work. Would probably be ~100FPS slower than the 322 because you'll most likely fill the case up before you max out pressure but it's another option that's been available lately.

What primers are you using? I use Rem 7 1/2s in 222/223 sized cases. Got tight on Federal match primers and was impressed with how they did.

Reloading Data Center

www.hodgdonreloading.com

You can also look up 22-204 Ruger load data, they're very similar.