Re: I think I might need a more explosive bullet?
The Rem power locks are crap for consistency and perform just like you noted.
Here is my favorite .223 load and it is one that exceeds all known .223 parameters. I have flipped 8 pound chucks 2 feet in the air at 545 yards with this load. For some reason, it is the perfect combo of ingredients to wring the absolute highest safe velocity from a .223 known to man! Ok, here it is:
Match prep a Winchester case and cull out the garbage pieces. Then seat a Winchester WSR primer just below flush. Then put in 26-27 grains of Alliant's RL10x and seat a 40 grain Sierra Blitzking .010" off the lands. When chronoed through a 24" barrel, this load will do a tad over 4000 fps with safe pressure! It gets a little sticky around 80 degree temps, but still doesn't loosen primer pockets.
I got a friend of mine onto this same load last fall, and he said it shot 3/8" groups and printed 4 minutes higher at 500 yards then his previous "hot load".
A ballistic historian will note that this load far exceeds the original ballistics generated by the .220 swift with it's 48 grain hollow point! It is a super .223. Hundreds of chucks can attest to the potency of this load!
If it's not far, it's boring.