I have a Browning A-Bolt 7rem.mag w/Boss. Currently I'm shooting Win. Supreme Fail Safe in 140 gr. Only shot at 2 deer with it & dropped them both 1st. shot. I have'nt really messed with my boss, except setting it by the chart that came with it according to bullet wt. It shot pretty good & consistant, but I would really like to drive tacks with it. Just like to see if anyone else has one like this & how they have theirs set up. I know best way to do this is go to the range, just had'nt the time lately like I'd like to. Hunt safe & support the N.R.A. JSHARRIS51

In a review of the BOSS equipped rifles when they hit the market over a decade ago, the people testing the rifles (in a variety of calibers) were not able to improve much on the Browning recommended settings per various bullet weights. (Perhaps experimenting with a quarter turn here and there for a given loading might help, but I'd not be surpised if their recommended setting performed best.)

That being said, their sample 7 mm Rem Mag A-Bolt was turning in .28" groups @100 yards with some ammo, so apparently, the rifle indeed has potential!

Good luck with it...take it to the range with a variety of factory loadings, and you might be able to find a factory load giving 1/2" groups!

I have found that Hornady Custom or Light Magnum tend to be the most consistent factory rounds made. They're definitely the most accurate out of my guns.

I'm looking forward to seeing some of those rounds in the WSM category. Right now the field is limited, but as the short magnums gain acceptance that should change.

Every rifle is different ,but I've found the Hornady Custom and Federal TBBC and N.P.'s to be the the best out of the box accuracy from box to box and haven't found Win. and Rem. to be as consistent.
If I do my part they'll give me 1/8 to 1/4 inch groups at 100yards out of my Rem. 700. Even if I get a flyer the goup will be only 3/4" with the Hornady and Federal and that flyer isn't the ammo's fault.

Unfortunately there is no way to accurately predict which load will be the most accurate in your rifle.Each rifle is an individual and it takes some trial and error to determine the best load for each one.