I'm coming to the conclusion that quality of the bullet itself and getting it seated straight are the most important.
Any of 4064, Varget, H-380, or H-335 (or maybe a dozen others) may work depending on bullet weight. I've also had exceptional success with Nosler BT's. I use 50's in my AR.
I use Federal Match primers. Just started with them and they worked out well.
Since it's a bolt gun, you may try Lee collet dies. Neck sizes only and keeps the neck straight. If you try to neck size only with regular dies, the neck may end up crooked because the body of the case isn't held in alignment.