I've put hundreds of round through a BOSS equiped Stainless Stalker trying to find the optimum method for tuning these beauties.
The best method I've found so far is to:
- Set the BOSS to a recommended setting, or one that is close according to the manual. Approximate if you have to.
- Stay with the factory COL, I've tried different lengths but ended up chasing my tail by changing the COL, then ending up messing it up by following that change with a tweak to the BOSS.
- Follow any ladder style load development method to determine that point of powder charge insensitivity where if you vary the powder charge by (e.g.) 0.2 grains the center of a group doesn't change.
- Adjust the BOSS to tighten up the groups. This takes the place of varying the bullet depth step which would normally follow on a non-BOSS equiped rifle. This is fine work. If you change the setting any more than 2 increments per group you risk jumping over a good group. Also tracking your groups in a log book really helps.
When you run your test groups ALWAYS allow cooling time between each shot. I've found that by the time the 3rd shot is taken, the barrel has heated up and walks off-target - took me many range trips to figure that one out. But it makes sense as these are hunting rifles first, designed for a limited number of shots in a string before things change. That's a desgin trade-off, rapid fire accuracy vs weight.
Lastly, the stocks are so soft that they CANNOT be muscled into position on a bi-pod - this will cause horizontal stringing. Allow the rifle to naturally find the target and use a light grip.