RL17 is impressive in the 308 with 208 gr amax bullets.
I think RL19 would probably do better in the 338-06 with 250 gr bullets but I still got good results.
In 338-06 I have a feeling RL17 will really shine with a 225 gr TTSX.

Chrono was about 10 yards away.

338-06*
24" A+B barrel, new WB brass, CCI primers, 56gr RL17, 3.35 col, 250 gr GK
2505 FPS
You could probably push it with fire formed neck sized brass and get 2550.
A 338-06AI and you could probably get very close to 338 win mag speeds out of it.

No pressure signs in the WB brass.
Reformed new win brass with the same load showed pretty flattened primers, but no brass
flow and no hard bolt lift. It was close to max though.
The new WB brass holds slightly more powder.

This load at 2500 fps is supersonic out to 1000 yards and carries 2000 fpe out to 400 yards.
Recoil is stout, but I would not consider it abusive.

My feeling is with neck sized brass and hang the bullet way out you could easily run 250 gr Scenars at 2550
with a 24" barrel and they have a BC of around .675. The GK bc is around .585, but is pretty cheap.

.308*
22" 10 twist factory savage sporter barrel.
New win brass, CCI primers, test loads of 44-49.5 gr of RL17, 2.95 col, 208 gr amax.
44-2318, 45-2376, 46-2415, 46.5-2435, 47-2478, 47.5-2505, 48-2540, 48.5-2560, 49-2575, 49.5-2590

Win brass holds slightly more powder.

No pressure signs up to 48.5 gr.
48.5 gr showed pretty normal primers, no brass flow. This will be my max at this col with new win brass.
49 gr showed more flattened primers and slight brass flow.
49.5 gr showed more flattened primers and more brass flow with a slightly stiff bolt lift so I stopped there.

This load at 2560 is supersonic out to about 1300 yards and carries 1200 fpe out to 800 yards.
Recoil is not that bad, especially after shooting the 338-06 with 250 grain pills.

With a 26" barrel you could definitely hit 2650 safely with this load, new brass at 2.95 col.
Fire formed neck sized brass and hang the bullet way out and you should be able to hit around 2700 fps with a 26" barrel.

.243*
Also clocked another new RL17 load, 243 with 80 gr TTSX over 45 gr of RL17 at 3300.
That was in a Browning BLR. It has a pretty short barrel like 20".
I could probably push it a bit more as I saw no pressure signs.
The max load in the barnes manual is 45.5 gr, 24" barrel, 3467 fps.
Should be a smokin Hog round.