Re: 223 recipe for high volume CQB practice
For up close practice, I'm going out on a limb and thinking that upper velocity isn't your goal but cycling the action is paramount.
My AR stops reliably cycling the action around 22gr of H335 in the case. For practice ammo I use 25.5gr and it shoots well in both my AR and my bolt action, even if the velocity isn't where someone else might wring out the case at, it shoots fine to 500yd.