There are not many bad choices for a 308. I started using 4895 and 4064 when I got into reloading for 308. Both are good, but I've gotten a little better speed and accuracy with RL-15 and Varget. I really cannot tell the difference between the 2. Never loaded for 243, so I can't say how any will work in it.
The main reason I choose Varget and RL-15 vs others is their ability to be consistent over a wide range of temperatures that the others will not. It will often be 100+ in August and in single digits in January here. That can mean 100 fps difference with some powders. A load that is perfectly safe in winter could be over pressure in summer. You will still see velocity and pressure dfferences with any powder, it just won't be as extreme with the RL-15 and Varget.
The main reason I choose Varget and RL-15 vs others is their ability to be consistent over a wide range of temperatures that the others will not. It will often be 100+ in August and in single digits in January here. That can mean 100 fps difference with some powders. A load that is perfectly safe in winter could be over pressure in summer. You will still see velocity and pressure dfferences with any powder, it just won't be as extreme with the RL-15 and Varget.
