I have a Martini Cadet chambered in .256 Win Mag. It has turned out to be "bug-hole" accurate with a 87gr Sierra & H4198 powder load. Most of the older data I have lists "4198" as a good powder in this caliber. So does 4198 means "H4198" or "IMR4198" in these older manuals? My problem is that my H4198 canister is almost dead empty while I have 2 lbs of IMR 4198 ready & waiting. As everyone knows its not so easy to just go out & get some powder. Is the load data between the 4198's interchangeable (assume starting at min loads)? I have several bullets 60,70,75,87 gr that I would like to try.
Thanks in advance for any comments or info!