Don't ignore Ramshot LRT
Since RL33 has become unobtanium, gone way up in price, and I'm nearing the bottom of my last jug, I thought I'd test out some alternatives for my .338LM Improved 40 barrel (36") with 300gr Hybrids. With 106.5gr of RL33 I was getting 3065fps, and while I was able to push it to 108gr, the former was a pretty darned accurate load.
So this past weekend I decided to try some other much easier to get powders. While I have a bunch of N570 I use for shooting 285 Flatlines in this barrel, I mostly use that powder for .300NM loads and prefer something slower for 300s. But I do have a bit of Ramshot LRT and 24N41 and decided to run some pressure ladders.
24N41 is a lot like N570, with pretty bulky kernels. I couldn't stuff more than 107gr in the case, while LRT I could go slightly compressed at 112gr. None of these loads displayed pressure signs.
24N41
min 102gr - 2903 fps
max 107gr - 3084 fps
LRT
min 105gr - 2928 fps
max 112gr - 3133 fps
So 24N41 was just a tad slower than RL33, but look at that velocity range with LRT? It may end up being a bitter fit for this combo. The only question now is how consistent it is? I've had mixed results in the past with vanilla .338LM using LRT because it felt too slow, but like using LVR in 6ARC, this powder might be really well suited to compressed loads in .338LM Improved