Been using RL-15 in my 375H&H for bullets ranging from 235 to 350gr with excellent results for several years. Now I'm working up a load for Barnes 250TTSX. Couldn't get groups better than about 2 inches no matter what charge from a rifle that puts everything else under an inch.
Loaded up some rounds with varying charges of H4895 and IMR 4320 and the largest groups were under an inch.
For some reason it seems RL-15 doesn't like the 250TTSX.

Quote: For some reason it seems RL-15 doesn't like the 250TTSX.
That would make sense unless your previous bullets were all jacketed since (hypothetically) the copper solids produce higher chamber pressures than jacketed bullets? Might explain why the slower powders put you back in the sweet spot. CB

The 235's were TSX and Speer, the 350's were Woodleigh PP and solids, the 300's were X and TSX. All under 1 inch all with RL-15.
The 250's wouldn't group with any charge from min to max with RL-15 but anything with 4320 was very nearly touching. Just baffles me.
On a similar vein, I have a M700 in 30-06 that doesn't like 165gr bullets. Shoots anything else I have fed it to better than MOA but any 165 is 2 MOA at best.
Just bad juju.

Maybe. 250 TTSX's might move pretty quick on here if you want to move them along. You know, outa sight, outa mind. Sounds like you gave them a good work over.