Could someone please give me some safe starting data (min/max)for loading the .257 Weatherby with IMR 7828. I will be using 100 Grain Barnes TTSX bullets. I've had good luck with this powder on another Weatherby and would like to try it again.
Mine hits 3505 avg with 71.5gr out of a 24" Vanguard with 100 gr TTSX. So far shoots them about .70" on average. Pressure signs at 72gr for me. About 30-40 fps slower and less accurate at 71gr. Others will provide you with higher loads but that was where my gun topped out. Lee
The latest version of the Barnes Reloading Manual does not have data for the Tipped TSX in the .257 Wby mag, but does have info for the standard TSX bullet. I am quite sure you will be safe using that data for the Tipped bullet. I have done this several times now with the new Tipped bullets and have found the loading data for the regular TSX to be quite safe.
For the .257 Wby Mag using the 100 grain TSX and IMR 7828SSC powder Barnes suggests a minimum load of 66 grains for 3314 fps and a maximum load of 71 grains for 3521 fps.
Even though Barnes tested the IMR 7828SSC powder, this data will work just fine with regular IMR 7828 powder.
Sherm, I think you should try RL22. I just got back from the range today and I shot 3 into 7/16 w/ 72 gr and a 100gr TTSX at 3680 from my 26" Broughton #4 barrel. It does the same ar better with the TSX or you could use the 110 Accubonds and 7828. Seem to recall getting 3400-3500 before hitting on the RL22 load.