I am loading for a friend's Browning S.S. A-Bolt in .30-06. I am fire forming the cases (Lapua) with Nosler 180 gr. B-Tip bullets, but will do the hunting load with 180 gr. North Forks. I am after 2700 + fps.

The factory was no help in information on tuning the BOSS system with this load. I have all of their standard information, which is for a Hornady and Federal load in 180 gr.

Does anyone have any recommendations for settings in this load?

Thanks,

Sam
eclemmons@hotmail.com

Usually, the factory starting point for commercial 180 grain loads will be pretty close for your handloads. Try it there, and see if they group well. If they are 3/4" or less at 100, call it good.

The problem with their listings for the factory ammo is that one is 5 and one at 10.

This is why I was looking for something that started me a little closer.

Thanks,

Sam

I am shooting 180 grain Ballistic Tips at 2750 fps out of my BOSS equiped M-70 .30-06. I found that NONE of the recomended "sweet spots" were even close to where I was able to get the best accuracy. I tried the recomended settings and ended up with 1", 200 yrd 3 shot groups with the BOSS set at 2.3, well off from the settings Winchester suggested.

The most interesting thing I found was that when I replaced the ported barrel weight with the CR weight my point of impact shifted by 4" up and 2" left @ 100 yrd. I also had to retune the piece for the best accuracy. (even though the ported and unported versions weigh the same)

OK, I was probably lucky... 3/4" groups right off the bat in my '06, 1/2" in my 223. On my '06, I used the muzzle brake version exactly once. As soon as my eyes rolled back in place, I put the other BOSS on.



I haven't tried this method, but there are good physical and statistical reasons that it ought to work very well.



Set up five targets. Warm your barrel up with a few fouling shots. From then on, take it SLOW so the barrel is at fairly constant temperature. Set the BOSS at 0. Shoot 3-5 shots at target 1. Set the BOSS at 2, and shoot 3-5 at target 2. Continue until you have shot all 5 targets, and are at 10.



Find the center of each group you have shot.



On a fresh target, plot the group centers. You should see the centers moving in an elliptical pattern. It may well be that before you get done with the sequence, the pattern will begin to repeat.



From the pattern, figure out which BOSS setting will put you out on the end of the ellipse. Alternatatively, find the two groups that show the least center-to-center change, and pick a setting between those.



Trying to do it by looking at group size will drive you crazy. A five-shot group is so statistically weak that you can expect plus or minus 50% variation in group size, just from random variation. Three shot groups are worse than that. This method converts the problem to tracking means instead of ranges, and that is a much easier thing to do.



Good luck... hope this helps.