According to the Sierra manual, the max load listed is 43 grains for a 60 grain (3700.) 41.1 for a 75 (3500) and the 34.6 for a 90 (3000) and 34.2 for a 100 grain (2900.) These sound like low charges, but be aware that a 243 has a much different burn rate than a 308 even though it is the same case. these are MAX loads, make sure you start much lower than that and use a chrony. I hope that helps.