I found my notes on load development for my 338Fed. Rifle is REM 600 with a 21" barrel. All brass is resized RP 308WIN with CCI LR primers. It was shot at 100yds on a cool 50degF day with less than 5kt wind (at my back) in GA.

RL-15/185gr TSX (All loads grouped 1.5 to 1.75")
46.0gr: 2584, 2551, 2573
46.5gr: 2659, 2631, 2632
47.0gr: 2687, 2680, 2697

RL-15/200gr Hornady SP (All loads right at 1")
46.0gr: 2474, 2519, 2510
46.5gr: 2541, 2551, 2514

RL-15/210gr NP
44.5gr: 2412, 2372, 2366 (3" group)
45.0gr: 2409, 2385, 2399 (1.5" group)

WIN748/200gr Hornady SP
49.0gr: 2505, 2524, 2506 (1.0"group)
49.5gr: 2515, 2494, 2500 (1.5" group)
50.0gr: 2532, 2538, 2535 (2.5" group)

WIN748/210gr NP
45.2gr: 2430, 2425, 2411 (0.8" group)
45.7gr: 2485, 2459, 2485 (1.0" group)

IMR4895/200gr Hornady SP (All loads less than 1")
46.0gr: 2491, 2493, 2501
46.5gr: 2528, 2508, 2521
47.0gr: 2553, 2546, 2555 THE WINNER

I also tried the 185gr TSX with WIN748 and IMR4895. The results are not worth posting. Very inconsistant MVs and groups. I was torn between the 210NP/WIN748 load or the 200SP/IMR4895 load. In the end I went with the latter since I use IMR4895 in my 7mm-08 and 223. Commonality of components helps especially with the prices lately. I hope this helps...