That is wrong. W296 and H110 are the same powder, not Lil'Gun.
If I were you, I'd take a hard look at Accurate 1680. It is the powder invented for 7.62x39, and it is a universal powder (sub-sonic or super-sonic) for 300 Blackout, and I found some 450 BM loads on Ramshot's online load-guide.
I've loaded 223 with 1680, but it is not ideal. It works better with very light bullets (45gr or so). It is very similar to the powder Russian steel-cased ammo is loaded with, but just a touch faster, so even less reliable. I'd really rather go with Win748, Ramshot Xterminator, Accurate 2230, or H335 for a better performing 223 powder.