I have a 300H&H and was going to start reloading for it. I want to use 200 grain bullets. Any help will greatly be appreciated since I just started. I was looking at retumbo but cant find out where to start or what max loads would possibably be.
FWIW I suggest you consult the latest Nosler Reloading manual. The information is there. I also suggest you do not take anyone's maximum load for any cartridge off the internet, without working up to said load in your rifle.
In an old notebook I found that IMR 4350 was the most accurate powder when this was written down. (This was probably between 1978 and 1981.) Somewhere between 59.0 and 65.0 you should find an accurate load. The chronograph I was using at the time wasn't real trustworthy. But I have the note that 65.0 was showing pressure signs and the muzzle velocity was ball park of 2810 This was an OLD Rem 700 that did not belong to me. But it was getting 3/4" 5 shot groups at 100 yards. This was before muzzle brakes became popular. I also noted that it wasn't something I wanted to shoot very often.