Model 70 BOSS

[RiverRider]

Has anyone ever figured out a quick and easy way to dial in the BOSS adjustment on a Model 70? I have one in .25-06 that I'd love to get shooting with handloads.

When these rifles were shipped from the factory, they came with special instructions on dealing with the BOSS setup. The information included the setting to go to for different weights of factory ammo. I don't believe these numbers provided were meant to be absolute, they just gave you a good starting point so you wouldn't have to burn through a half dozen boxes of ammo trying to find the sweet spot. Unfortunately, for .25-05 they provide a starting point for only three bullet weights: 85-, 90-, and 117-grain. I've fiddled with 110-grain Accubonds and have seen some good but inconsistent results, and I think the rifle can do better. The problem is that the BOSS has such a wide adjustment range I might shoot the throat out of it before finding the sweet spot.

I'm going to go another direction and try 75-grain V-Maxes next. That's really a better choice for the work I plan to do with this rifle anyway. I don't need to shoot 110-grain Accubonds when my .280 is shooting 150-grain Partitions so well; the .25 can be my screamin' long-range varmint buster. Who knows, I might get lucky and stumble into the best BOSS setting by accident...but if someone knows a better way than relying on luck, I'm receptive to enlightenment.

 

[Oldtrader3]

I have 3 different Browning BOSS charts for the settings which are somewhat different numbers. Only one of them has a .25-06, 110 grain (Hornady) setting it is listed as 3.5 on the BOSS device which is the same (on one list) for the 100 grain. I would bet that you are within .5 with that setting?

What I have done with the three Winchester and Browning guns that I have owned with BOSS devices on them (.280, .30-06 and a .243 Mini Medallion), is to jump +/- 0.3 BOSS range each test load. Until you hit a bracket. Presently, I only have one rifle (.30-06) that has the device. It does help with accuracy but can be a trial to find the sweet spot.

The other weights are listed as (Nov 2007):
85 gr Nos BT=2.6
90 gr Winc=2.25
100 gr Hornady=3.5
117 Federal=6.0

Good luck with that. Let me know if it works for you?

 

[RiverRider]

Thanks for the response Oldtrader.

I happen to have collected the Browning numbers somewhere along the way, and if they're sueful to you here they are:

25-06 Rem. 122 6
25-06 Rem. 117 Federal 6
25-06 Rem. 100 Hornady 3.5
25-06 Rem. 90 Winchester 2.25
25-06 Rem. 85 B Tip. 2.6


Here are the Winchester numbers:

25-06 Rem. 117 Federal 6.3
25-06 Rem. 90 Winchester 3.1
25-06 Rem. 85 B. Tip 6.3

As you can see there seems to be not much similarity. I suppose the difference in the barreled actions is enough that the settings just won't be similar.

I thought I was on a sweet spot at 7.0 with the 110-grain Accubonds, but as I said the results just weren't all that consistent.

My neighbor has a Model 70 in .30-06 with BOSS and that thing is a tackdriver. That was the reason I hunted down this .25-05 with BOSS. His has been well behaved and seems to like just about any handload he feeds it (he's been handloading some for about the last three years, buys heavy-barreled rifles that shoot lights out---I've never seen such buyer's luck!---and thinks he's P.O. Ackley...and the guy doesn't even know who P.O. Ackley is!).

I guess I'll just move along to the 75-grain V-Max and see what happens. In any case, it's good to know there's someone else around to bounce this stuff off of. If I learn anything useful I'll be sure and post it here in these forums!

 

[RiverRider]

After re-reading your answer a little more carefully, I see that you only have one BOSS-equipped rifle at present, a .30-06. I'll share what I have:

Here are the Winchester .30-06 numbers:

30-06 Spfld. 220 Winchester 9.6
30-06 Spfld. 165 Hornady 2.0
30-06 Spfld. 150 Federal 1.8


Here are the Browning .30-06 numbers (for the A-Bolt):

30-06 Springfield 220 Winchester 10-10.5
30-06 Springfield 180 Hornady 10
30-06 Springfield 180 Federal 5
30-06 Springfield 175 Federal 7.2
30-06 Springfield 165 Hornady 3
30-06 Springfield 150 Hornady 3
30-06 Springfield 150 Federal 1.5

 

[Oldtrader3]

I am shooting a Model 70 (USRAC) with the BOSS at 3.0 with 165 Partition or Ballistic Tip bullets. Thanks for the numbers.

 

[SJB358]

I have an M70 338 with the BOSS and tuned it the same way as Charlie did. Started at the closest reference point and then jumped by .3's till it started opening up. Then I would tune backwards by .1's. Rifle seems to have worked well for me. Wouldn't buy another but this one doesn't bother me at all. Scotty

 

[RiverRider]

I put this rifle up for sale because I got tired of having the BOSS as another variable, but just before it sold I tried some 75-grain V-Max driven by a healthy dose of Ramshot Hunter (I started at 57.5 and went to 60.0) with the BOSS set at an arbitrary 5.8. The highest charge gave me a 3-shot group measuring just under 1/2 inch. I was tempted to hang onto it and keep experimenting, but cash is pretty tight these days and I had a chance to get all my money back out of it. I now have a brand new Model 70 in .25-06 on the way, and in fact my FFL dealer has it but I just have to wait for him to get back in town so I can pick it up.

I'd kinda accepted the idea of using .25-06 my big varmint/predator rig using 75-grain V-Max and .243 as my light big game rig using 100-grain Partitions. We'll see how it all pans out.