I've been experimenting with my Browning 223 Remington.

So far I've only shot 30 rounds for testing over the chronograph but I have achieved 2,600fps with 20.6gn 2206 without any apparant leading.

you should be able to get another grain and a half in there no problem.
I use IMR-4895 [which I think is 2208] for some over 2700 fps and closer to 28 without the coating [in a 1-9 twist] so you got plenty of room.

Those will hit like liquid death. Whats the accuracy like?

Years ago I loaded some 95 grain RCBS mold cast bullets in my .243. The book said load should be around 2500. A guys chronograph said 2900 fps. His chronie seemed accurate with other loadings. I was using "felix" lube and getting no leading. So my grandson and I tried them on a spike buck. Grandson shot and deer ran a few feet and stopped. I had a perfect easy shot, I see no way either of us missed. Deer ran off and not a drop of blood found.