While I wouldn't necessarily recommend it, I would bet that it would work just fine. I've loaded a lot of rounds with H110 (identical to 296) and have more or less figured out it's limitations. The main thing I have noticed is very inconsistent ignition when loaded below 30,000 psi. Mainly noticed this in 454 Casull and 500 S&W with lighter weight bullets.
While not reduced loads, I have even loaded 458 Lott and 460 Weatherby with H110. Started with a QuickLOAD calculated 30,000 psi and worked up to 57,000 psi in the Lott and 83,000 psi in the Weatherby.
If I had a bolt gun to test it in I would try some 223 loads. Don't think I would want to start off in a semi auto though.