cast - that is identical to my 280 Rem cases. I don't think you're going to do much better than 2850 with a 160.
As a guide, I'd feel comfortable exceeding 280 Rem data, known pressures tested data only, by 2-3 grains. 2-3 grains should gain you 75-100 ft/sec over 59-60K psi data. Looking over my manuals, esp Hodgdon's website, their 280 loads top out at 2700 and change at 49K CUP (note CUP is significantly different than psi). Nosler is the only data source I have that breaks 2900 and then only with MagPro. Plus, I've struggled to reach Nosler's velocities most of the time.
I'd look strong at my go to's for velocity: MagPro, IMR 4831, IMR 7828, RE 22. You also might be able to cram enough RS Magnum and/or RE 25 into a 280 case as well.
I'd also look at 280 AI data - and not exceed it in any way, shape or form. Hodgdon show 280 AI data with pressure testing. They show IMR 4831, 55.5 for 2847 at 62K psi, IMR 7828, 58 for 2849 at 61.3K psi. I'd look over more 280 AI data to look for do not exceed limits - I'd also evaluate if the author of the data held it to the 280 Rem pressure standard of 60K psi or not. I see that Nosler AI data and JB's 280 AI article exceed Hodgdons and Sierra's by a bit and suspect they ran pressure up to 65K psi in their 280 AI loads. I'd back off couple of grains from Nosler and JB's load data in the regular 280 when trying to determine 65K psi loads.
I think I'd use MagPro, RE 25, RE 22, IMR 7828, IMR 4831, Magnum, load using 280 data to start, stop adding powder when I hit 2850. If you can get enough RE 25 and Magnum into the case it may do 2900. I would not exceed 280 AI data.
I ran the numbers through my modified Powley and it suggests 57.6 gr of a powder a bit slower than IMR 4831 for 2894. This is in line with the empirical book data as well. Understand that these powley numbers are idealized with the perfect powder - reality dictates 2894 is ideal - 2850 again looks like a wise limit.
Good luck.
