I just went through a Model 70 in 300 Win Mag w/ a BOSS for a good friend that wanted me to fix up his rifle and find a good load as well.

Well after taking the trigger from the factory set 6.5lbs down to 3 pounds, Re-Blueing several parts and spots, and a good cleaning, I've loaded several rounds. He's set on shooting 150s and shooting them pretty quick so i chose the 150 Accubond since Whitetail Deer was on the Menu.

My Question is on where to set the BOSS w/ these 150s. He's got it set on the first mark and on Zero. The BAR I've loaded 150s for is set on the third mark but, I don't know if this 70 will act the same as that BAR.

Are any of you shooting 150s or 165s through a BOSS?

Which setting did you find the best grouping?

I could just do a trial and error run but, I hate to burn up too many rounds so, I figured I try and start at a setting that worked for some others.

Thanks,

Reloader

Have you tried talking to the folks at Winchester in Utah? I bought a 338 BOSS couple years ago and they were helpful at the time with some basic settings by bullet weight based on WW ammo.Used to have their number until I moved recently and everything is still scrambled or packed away still. If I find it anytime soon I'll post it.
Ron

Please share what ever setting works for you with the rest of us. I found the settings for my BOSS-equipped M. 70's (.270 and 7mm Mag) by trial and error because the recommended settings weren't great. Once I found the sweet spot I was delighted. My avitar is a quick four round group shot OTB with the .270 at 96 yrd.s. The group was actually better before the barrel heated up and the rounds started to creep down and to the righ.

Good luck!

quote:

Have you tried talking to the folks at Winchester

Yes, I called them last week but they said 180s were the lighest bullet they shot through the Bolts but, They had tested 150s in the BAR 300 WM . Seems like they'd test the same weights in both set-ups since they are both the Same cals. They did tell me not to pay any attention to the BAR settings which only made since because the bbls are attached in a different config.

They said 0.9 worked the best for them w/ 180s so I just started at 1.0 and ironically that turned out to be a great spot. I shot some groups at 1.0 and then tried 2.0 but, the groups opened alittle. I put it back at 1.0 and proceeded to sight in.

The BOSS must work. This rifle shot great, I loaded 150 Grain Nosler Accubonds on top of 66 Grn H4895 in R+P Brass w/ Fed 215 GMM primers and this baby shot Quarter sized groups at 200 yards. Alot of 300 WMs don't fair really well w/ 150s but, this one sure did. He wanted it sighted about 3" high at 100 and at 200 it was 2.25" high dead center vertically. I'm glad it was that easy to work up a load for this rifle especially w/ the bullet weight he wanted to shoot. I have a feeling that the BOSS helped me out in the Accuracy department.

Reloader

FYI--I had 2 boss equipped brownings and both shot real well at the recomended settings from the factory. Proabably would still have them if they had the non ported screw on end at that time--the boss was just too loud. One gun was a 270 BAR and that darn gun would shot 3/4" with almost any bullet and would even shoot most weights to the exact point of impact. THAT GUN WAS A KEEPER..dumb me.