I have a Browning A-bolt II in .338 Win Mag, equipped with the boss system. My question is, is there a formula to figure out where to set the boss for loads not listed in the manual? I thought about finding the closest load to what I will be shooting in the manual and then just adjusting from there, but thought someone in here may have a better suggestion? Your thoughts?

Thats a good idea....Also, a video comes with the browings with a boss system (or supposed to) and that explains all about the boss system. If it didn' t come with the video, I would try the closest load to whats in the manual, like you said.

When I had a boss equipped rifle the sweet spots were not where they were supposed to be even for the loads given.Trial and error was the only way to find out where the sweet spots are.I discovered that I spent more time and ammunition adjusting the boss than I do in developing handloads for a rifle and the results are no better with the boss than with handloads and no boss.For that reason and the extra noise and muzzle blast the boss muzzlebrake provides,and the reduced velocity of the shorter boss equipped barrel, I sold the gun.

Not all of the sweet spots are listed in the manual. However this is a link to the Browning web site that has them listed. http://www.browning.com/faq/detail.asp?ID=109