I just purhased a 7mm RM Stainless Stalker w Boss, used. It is supposed to shoot bergers well, but the stated velocity seems about 75-100fps slow. I have the load info and boss setting. So my question is, would I expect that the Boss sweet spot could be radically different if I use the same bullet/seating but a different powder? I want to try Retumbo/H1000, but the current load is RL19. Expect velocity is 2860, and I hope for 2950. PS does anyone think that changing the bedding material from the factory "goo" mentioned negatively impacts the effectiveness of the BOSS? This new gun has an aftermarket stock(medalist).
Bedding a Browning A-bolt with BOSS
- Thread starter Striker77s
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Hondo64d
Well-Known Member
Finding the sweet spot in a BOSS or any other barrel tuner is all about harmonics, and any change in components will change the harmonics. So, yes, another load will require you to retune the BOSS.
But, that's kinda the beauty of the BOSS. Find a load that produces the velocities and the SDs you want, then tune the BOSS to the load. About 95% of what I read about the BOSS supposedly not working is from people that will not adhere to the directions in finding the sweet spot. Most get impatient and start jumping around in their adjustments, hoping they find the magic setting.
As far as replacing the factory bedding, goes, a proper stress free bedding job with a quality bedding compound never hurt any rifle.
John
But, that's kinda the beauty of the BOSS. Find a load that produces the velocities and the SDs you want, then tune the BOSS to the load. About 95% of what I read about the BOSS supposedly not working is from people that will not adhere to the directions in finding the sweet spot. Most get impatient and start jumping around in their adjustments, hoping they find the magic setting.
As far as replacing the factory bedding, goes, a proper stress free bedding job with a quality bedding compound never hurt any rifle.
John
cstilt
Well-Known Member
I don't have a perfect answer for all your questions, so I can only state what I know. When I switched between different 150gr factory loads in my rifle, the BOSS setting would sometimes be very different. I'd imagine that changing anything in the load could have a large change on the accuracy. Rifles all suffer from the butterfly effect. Change one tiny thing and it can have a completely different outcome.
I will tell you that my 270win is slower than it should be. I'm currently getting 2850 from 59gr of H4831 when it should be 2900s. This is because of the BOSS and false advertising. They say my rifle has a 22" barrel. That's 22" including the BOSS, just the barrel its self is 20". I'm betting yours is a bit slower than it should for the same reason. Measure it with a cleaning rod with the BOSS off and I'll bet you're 2" short of what you were thinking, I sure was.
This past weekend I finally gutted the plastic bedding in mine and replaced it with Devcon. I've not shot it yet though. My thinking was plastic like things can become harder or softer if different temps, so that stuff might too. Didn't like the idea mushy stuff behind the recoil lug either. We'll find out if I did the right thing when I'm able to go to the range.
On a side note, look into the Timney trigger springs on midway. I replaced mine with the 2lb spring and it feels so much better.
I will tell you that my 270win is slower than it should be. I'm currently getting 2850 from 59gr of H4831 when it should be 2900s. This is because of the BOSS and false advertising. They say my rifle has a 22" barrel. That's 22" including the BOSS, just the barrel its self is 20". I'm betting yours is a bit slower than it should for the same reason. Measure it with a cleaning rod with the BOSS off and I'll bet you're 2" short of what you were thinking, I sure was.
This past weekend I finally gutted the plastic bedding in mine and replaced it with Devcon. I've not shot it yet though. My thinking was plastic like things can become harder or softer if different temps, so that stuff might too. Didn't like the idea mushy stuff behind the recoil lug either. We'll find out if I did the right thing when I'm able to go to the range.
On a side note, look into the Timney trigger springs on midway. I replaced mine with the 2lb spring and it feels so much better.
Striker77s
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I bedded my A-bolt and found it did improve. According to some documents from Browning the goo bedding stuff was developed in conjunction with the BOSS system. I was also worried about the BOSS not functioning correctly once I bedded the rifle. I can say that my rifle shot better after the bedding and the BOSS still seems to function. I haven't done a lot of tests adjusting the BOSS since bedding it but I've done enough to see that it still changes my shooting pattern. I don't regret bedding my A-bolt at all.
I also agree with cstilt that changing your trigger spring will make a big difference. It was the first modification I did to my A-bolt.
I also agree with cstilt that changing your trigger spring will make a big difference. It was the first modification I did to my A-bolt.
I don't have the gun yet but am told the trigger spring has been changed to 2lbs. I'm going to start with the berger load recommended, if it shoots as well as recommended I will be happy. I just ran numbers at the velocity quoted and it fits my Zeiss z-600 very well.
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Shootin4fun
Well-Known Member
Yea, the spring will probably make a difference. I'm about to try to find the lightest setting on my factory Xbolt trigger. I lightened it once and it helped.
I also have a Browning BAR, and consider the trigger to be 1 of 2 weak points of the whole gun. The other is that the barrel is not free floated. I'm told "for an automatic" it shoots well. Well...I can often put 3 out of 4 in a .2 MOA group at 100, but 1 in 4 is usually about .8" - 1" away from the other 3. 4 shot groups at or under 1 MOA are common with this gun and my handloads. At 200 I'm lucky to get under 1 MOA though sometimes I'll pull a .5 or 1" group at that distance so that makes this a "within 300 yard hunting gun" for me.
The trigger is 2 stage, easy pull, stop, then a slight creep or "spongyness" wherein you can feel the trigger moving against resistance but hasn't released the sear yet. During that period I may be moving. Anway, I wish I could make it a nice crisp break but asking around, I haven't found anyone who can make it so. As a result I look to freefloated bolt action rifles to shoot tight groups at longer distances.
Shootin4fun
Well-Known Member
Jay & Hondo- thank you for your experienced advise on this! I may be taking possession of a BOSS equipped rifle next week. The advice to get work the ES/SD/velocity aspect of the round first, then vary BOSS adjustment from factory "sweet spot suggestion" second makes perfect sense.
In fact many times we find that a mid/light load gives the best accuracy, so I'm also interested in determing if a hotter (though less accurate) load with good ES/SD can be made to shoot more accurately with the BOSS.
Lefty7mmstw
Well-Known Member
I guess I'll chime in here since my a-bolt stainless stalker lh boss has killed around twenty deer in the last ten years with a 165 hornady. I use 78.0 rl22, 165 hornady fb bullets, win brass, and a 215 set to 3.34" for a .020" jump to the lands. This rifle will toss .4 moa for three, .8moa for 5, and around 1 moa for ten as fast as you can pull the trigger with this load. The rifle wears a 6-24x40 b&l elite scope and is stock other than a lightened trigger. The rear action screw needs lock-tite on these rifles as it likes to loosen whenever it wants to. I also lock-tited the boss at ten turns out since it really made no difference in the loads I shoot and it also liked to loosen. I've got around 1200 rounds on the rifle and it barely shows any throat wear, but I don't cook the barrel either.
