I have tried h4831, rl19, 7977 in mine. And for bullets 285eld, 265lrx, 225ttsx, and chucked a few 300otms too. I ended up going with a 225ttsx pushed by 82.1gr 7977, a bit slow (2860fps) but it groups great, its not really a long range gun anyways so that combo works. Rl19 gave the best speeds, but I couldn't seem to narrow in on the accuracy.
Its too bad that nosler stuck with a 3.4" mag length in their rifles, the 33 can gain a pile of case capacity when seated to fit in a rem 700 length action.
I'm getting 2910 fps with 225 gr. nosler etips and 78.5 grains of IMR 7828 ssc with great accuracy. RL19 was up around 2970 fps but accuracy wasn't great. I was also getting decent accuracy with the Barnes LRX 250 gr using 76 grains of IMR 7828. I'd have to double check my log but the muzzle velocity was somewhere around 2800 fps.
Brent C nailed it on the head. R-26.. very accurate and marginal temp stability.. If you don't like that 4831 sc works great for me.. I have custom gun with some freebore though. 2900 fps with the 250 elite hunter.
I use 7828 SSC in mine...I stopped a 77 grains even. Found it shot very well and didn’t want to burn 30-40 more rounds looking for the fastest node. My has a tapered throat so not standard—I load mine OAL 3.54 and adv speed of 2812 out of a 26.5 in barrel with a deviation spread of 18...shoots pretty good