I have been reloading for various 2506's since 1979. I have tried lots of bullets and have gotten best performance from Horn 100 gr Spire point, Sierra 100 BTSP, 100 Nolser BT, and Nosler 100 Partition. the partition is the best by far for terminal performance explosive entry wound but still always punches all the way through, even on shoulder shots through both shoulders. I have tried most of the 100 gr bullets made and all work well on lung shots without heavy bone. The partition has been reasonably accurate for me always less than 1" groups and usually around .75". The others will group between .5-.75.
For powders if you buy 2 lbs one of H4831SC and the other of RL22 you will find an accurate load. I have used both powders for numerous rifles and both powders have performed well. Most guns work well with either powder. I find that as I work up the powder charge the accuracy gets better as I get close to max loads. Experiment with primers and seating depth as I have found that some loads will group twice as good just by switching primers. I tend to use CCI BR2 with H4831 and FED 210Match with RL22. With 100 gr bullets I find that H4831 will produce best accuracy between 56-57.5 gr. With RL22 between 56-58 gr. THESE ARE MAX LOADS WORK UP SLOWLY!
You will love the 2506 a wonderful long range deer and coyote zapper I have around 4000 rds through my current rifle and my kids love to hunt with it. So much so that I rarely get to use it. :grin: Sorry about the length of this but maybe you can tell it is my favorite caliber