Update: Sweet spot setting for a BOSS equipped Model 70 .270 question

[40X Guy]

I have been shooting 130 grainers in my .270 M70 Winchester BOSS rifle the last few years at the recommended 1.1 setting on the BOSS and accuracy is very good. I am wanting to try some 110 grain Barnes TTSX bullets for upcoming deer season here in Pa. I have scoured the net for info but can't seem to come up with a number to start at. Browning's recommended settings are different than a Winchester's and they do not list a 110 grain either. Just curious if anyone may have a sweet spot setting to start with for a .270 with 110's or any recommendations?

Frank

 

[CaptainMal]

Re: Sweet spot setting for a BOSS equipped Model 70 .270 question

I currently have older Winchester BOSS Model 70's in many calibers. One is 270. Looked at my original book but it does not list anything for the 110. Now, so what? Those tuner settings are all relative to the exact load you are shooting. No way does any pre-published tuner setting become an absolute setting for everything of a certain bullet weight.

That silly book does say to use 1.1 for 130's and 2.5 for 150's. I have my 270 tuned for years with 140's and a BOSS setting of 1.8. Right at 3,000 fps., it is truly a MOA rifle as ALL my other BOSS rifles are, except for the 375 creature I put together. My 7mm BOSS and 338 BOSS are as delightful as the 270 one. All took fiddling for each particular load I built.

My suggestion is to start around 1.0 and test + - a little bit to find out what that particular rifle likes with the particular ammo you are using.

 

[fredhorace77]

Re: Sweet spot setting for a BOSS equipped Model 70 .270 question

Personally I would shoot it right where it sets and see what happens. Then move a few increments up and then down from ur current setting and see what happens. I often treat the BOSS System some what similar to my seating depth trials.

 

[Bigguy1951]

Re: Sweet spot setting for a BOSS equipped Model 70 .270 question

I haven't looked, but the Browning web site does give comparable info to the Winchester spec sheet. Don't know if it is there or not, but surely worth a look. It is online.

 

[40X Guy]

Re: Sweet spot setting for a BOSS equipped Model 70 .270 question

I currently have older Winchester BOSS Model 70's in many calibers. One is 270. Looked at my original book but it does not list anything for the 110. Now, so what? Those tuner settings are all relative to the exact load you are shooting. No way does any pre-published tuner setting become an absolute setting for everything of a certain bullet weight.

That silly book does say to use 1.1 for 130's and 2.5 for 150's. I have my 270 tuned for years with 140's and a BOSS setting of 1.8. Right at 3,000 fps., it is truly a MOA rifle as ALL my other BOSS rifles are, except for the 375 creature I put together. My 7mm BOSS and 338 BOSS are as delightful as the 270 one. All took fiddling for each particular load I built.

My suggestion is to start around 1.0 and test + - a little bit to find out what that particular rifle likes with the particular ammo you are using.

CaptainMal, I did start on the 1.1 setting as prescribed by the original book and rifle shot very well, I twisted the BOSS setting to .2 plus and minus and groups opened up to unacceptable size so that was the end of my experimentation. Left it on 1.1 and the 130 Accubonds i shoot out of it are accurate and dependable. I like Fredhorace77's and your idea of trying some of the 110's right where it sits and go from there. Thanks for the replies everyone and I'll keep the results updated within next 48 hours.

Frank

 

[40X Guy]

Re: Sweet spot setting for a BOSS equipped Model 70 .270 question

Update: Loaded up 2 rounds each 57.0, 57.5, and 58.0 grains of Win. 760 powder in new Nosler brass with the 110 TTSX bullets seated at 3.250 book COAL. Unscrewed the BOSS and screwed on the BOSS CR (conventional recoil) and set it to 1.0 figuring it is a nice even number to start with. Went with 58.0 load and they are humming. Maybe I got lucky? Definitely minute of whitetail..

Frank

 

[CaptainMal]

See it now. That CR must not have the recoil-reducing holes. Never saw one. What it is now is a tuner only.

Good luck with it.