CMG,
From a 20" Pac-Nor barrel I can touch 2500 fps with 225-gn bullets, and get 2640 fps with 200-gn bullets. These are actual speeds. I use IMR4895 for 225's and RL7 for 200's. JB reports speeds well into the 2500's with TAC and 225's but I have not personally tried it. Not a knock on Mr. Barsness, but I've rarely been able to even come close to other people's speeds in my .358's- they report one thing, I get something much, much less... so I'll believe it when I see it! :-) TAC is on my "to try" list, for sure, though.
IMR4895 does deliver 2500 fps, though.
I did mess with the 200gn X bullet, pre TSX, in my .358's. Velocities were similar to jacketed 200's; I'd have to dig way back in my notes for specifics, but that's a general statement of truth <g>.
My opinion- a 225 TSX is going to be painfully long in many .358's. It's gonna cost you some significant velocity. Case capacity is a bugaboo us .358 guys rassle with. WIth 225 Partitions, I am able to pack 51 grains of powder into the case and that gets me right up to 2480 fps. This is a HIGHLY compressed load; 51 grains won't even fit in the .358 case without some shenanigans, to put it in perspective.
Anyway, I have not DONE it, but the extra length of the TSX is gonna cost you 4-5 grains of powder, minimum, and that's gonna put you under 2400 fps.
That's what would happen in the two .358's I've owned and loaded for. If your rifle has a long magazine, it might not matter one bit. Just load them out longer.
Finally... I get the TSX thing; but seriously... at these types of velocities, what exactly is the worry with a 225-gn Partition?? That sucker is going to PENETRATE, and will most likely expand more reliably at those speeds too. My opinion.
