By all means, if you don't already have a manual, buy a couple. You can also get load information online from the powder manufacturers/purveyors.
What I use in mine with 140 and 160 gr. bullets is:
Powder: RL-22
Primer: Federal 210M (large rifle match)
Case: Whatever I have available
To determine the optimal COAL, seat a bullet a little long and try to chamber the round. Incrementally increase seating depth until the action just closes. Inspect the bullet to see if the lands have marked the bullet. Obviously, the first round you try to chamber will have land marks so you will need another cartridge for the final check on land marks. When the action closes easily and there are no marks from the lands on the bullet, the bullet will be seated just off the lands which is good for most bullets. Barnes bullets like a little jump so you should seat them a little deeper.