I recommend the Hornady 75 grain, 77 grain Nosler, or 77 grain Sierra bullets for 200 and 300 yards. You can use the more expensive Berger and Lapua bullets of the same weights but there is no need unless you a high master shooter. Seat the bullets to an overall length of 2.250 so that they will feed through the magazine. If you want to use heavier bullets at 600 yards, I would use the 75 Hornady AMAX, the 80 grain Nosler, or the 80 grain Nosler. I seat these bullets so that they are about 20 thousandths short of touching the rifling. You can experiment to find an optimum seating depth but it is a lot of work for minimal benefit unless you are a top notch shooter.
I have used Wolf small rifle magnum primers, Remington 7 1/2, CCI small rifle match primers and CCI small rifle military primers and saw no difference in the results. All these primers have harder cups and are more resistant to slam fires than some of the other brands. I would avoid Federal primers and Remington 6 1/2 primers. Pick one and go with it.
I have used Alliant RL15, Varget, VV N140, and H4895 powders for 200 and 300 yard loads and they all outshot me. Those are probably the four most frequently used powders but there are some newer powders that may be useful such as TAC and 8208 but I have not used them. I have used H4895, N140, and N150 at 600 yards and each of them were capable of shooting perfect scores with high X-counts at 600 yards. You can start at about 22.5 grains with any of these powders and work up from there. I never exceeded 24.0 grains with any of these powder/bullet combinations except for N150 with the 75 grain AMAX and 80 grain loads.
I would not waste a lot of time searching for the perfect load. Pick a powder, primer, bullet and work up a load. Unless you have a bad barrel just about any of the combinations will shoot into an inch or less at 100 yards which is far more than adequate for high power rifle competition. Unless you just have a lot of time on your hands and want to go all out on brass prep I would recommend simply full length resizing the brass (I use Lake City or WCC military brass and Winchester commercial brass). I trim the cases and sometimes clean primer pockets.
All my short line ammo is loaded on a Dillon 550B set up with an RCBS case activated powder measure. All of the above mentioned powders will drop within plus/minus one-tenth from the RCBS powder measure most of the time. The long line ammo starts with the same brass but powder charges are weighed. Having said that, one of my friends who is a great shooter loads his ammo on a Hornady progressive and drops his charges from a powder measure even for 600 yards.
Your time will be better spent practicing than trying to squeeze the last bit of accuracy out of your loads/rifle.
For more information go to usrifleteams.com and then open the National Match forum. There is a wealth of information on the site and plenty of people who are knowledgeable about Camp Perry and the upcoming CMP matches.