You can get lots of handloading recipes right off the internet. Hodgdon and Ramshot give lots of loading data, as do most of the powder makers. The bullet makers are stingy with these as they all want you to but their manuals. Do not use magnum primers for the .243 or .308. Those primers are for loads with large amounts of powder like the name suggests, and neither of those calibers warrants magnum primers. I'd also suggest you use powders that are not temperature sensitive so if you practice at the range all summer long in 80-90 degree temps, but hunt in much colder situations during the fall, your loads will maintain the same point of impact. I've been having good results with Hunter by Ramshot, and I believe that H4350 is also not effected by temperature. There are others, and you can get this info from the powder makers websites. Good luck!