There's data for the Hornady 68-Grain BTHP. I won't advocate using LT-30 with heavy bullets in .223, but when bullets are similar in construction, profile, and weight then data can be substituted---with the usual caveat that as a handloader you are on your own and are solely responsible for your own safety.
I use neither of these two bullets, but I'd be very surprised to see pressure measurements done by a single ballistics lab vary by any significant amount when the two are interchanged, with all else being constant.
