Here is some 25-303 data, should give you an idea of where to start. These were all in a 24" barrel, all R-P brass, all WLR primers. I no longer have this rifle but have thought about building another.
117 gr. Sierra BTSP
OAL 2.850"
IMR 4831
42 gr 2,770 fps
44 gr 2,850 fps *
100 gr Speer Spitzer SP
OAL 2.840"
IMR 4350
42 gr 2,858 fps
43 gr 2,938 fps *
43.5 gr 2,998 fps *
100 gr Speer Spitzer SP
IMR4831
OAL 2.840"
38 gr 2,626 fps
40 gr 2,708 fps
42 gr 2,821 fps
43 gr 2,901 fps
44 gr 2,979 fps *
44.5 gr 3,024 fps *
87 gr Speer Spitzer SP
IMR 4350
OAL 2.850"
44 gr 2,871 fps *
45 gr 3,160 fps
87 gr Speer Spitzer SP
IMR 4064
2.850" OAL
38.5 gr 3,850 fps
* = most accurate loads
Hope this helps.
Tony