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270 weatherby bullet choice

 
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  #15  
Old 03-03-2012, 12:14 PM
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Re: 270 weatherby bullet choice

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Originally Posted by 150pilot View Post
I was going to get Barnes 130 TTSX's but the Barnes site warns that it won't stabilize with that twist. My understanding is I need a bullet that isn't going to be too long for it's weight and that Barnes TTSX 110's should be fine. I may go that route, but I would have preferred something just a bit heavier.
Barnes' comments are wrong as most other manufactureres' sites on twist rate for bullets. It stems from decades ago data when folks chambered their existing barrels for a larger case and got decent results...as they tested them. Note the .30-03 cartridges 220-gr. bullet did great with a 1:10 twist. When it was replaced with the .30-06 and 150 grain bullets, they didn't shoot as accurate as 172-gr. heavy machine gun bullets which benefited from that faster twist.

Bullets need to spin at some small band of rpm's to stabilize at the velicities we shoot them at. The .270 Win. was first chambered with a 1:10 twist and that's perfect for 150 to 160 grain bullets in it.....at the muzzle velicities that case shoots 'em out at. A larger case producing higher muzzle velocities can use a slower twist. If that wasn't true, then folks shooting 155 grain 30 caliber bullets from rifles at 3000+ fps getting 1/2 MOA accuracy at 1000 would have never happened. And the 7.62 NATO round would not have been spec'd with a 1:12 twist for 147-gr. bullets leaving slower than the 150-gr. ones form 30 caliber Garnands' .30-06 1:10 twist barrels.

Shoot those medium and heavy weight bullets out of your .270 Wby.'s 1:12 twist barrel. It's great for that case size and velocity it produces. A 1:13 twist may even be better. Spinning bullets too fast tyically makes 'em shoot less accurate. Bullets with too much slight imbalance spun too fast make's 'em jump sideways a bit too far from centrifugal forces when the leave the barrel.
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  #16  
Old 02-17-2013, 11:35 PM
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Join Date: Jun 2012
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Re: 270 weatherby bullet choice

Bart that is the first explaination I have heard that made any sense.
I have a 1-12" twist 270 southgate.
I called Nosler they told me they doubted if 130 accubonds would stabilize. They even suggested I rebarrel.
Barnes said nothing longer than their 110 gr. would work well.
JBM Ballistic stabilization calculator gave me some relief thinking I could stabilize 130 and 150 gr. Grand Slams and 130 gr. Partitions.
Then I read all of the guys who actually shoot these rifle say they work just fine.
I guess it is time to load up heavies and see for myself.
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  #17  
Old 02-18-2013, 07:27 AM
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Re: 270 weatherby bullet choice

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Originally Posted by stevenm2 View Post
Bart that is the first explaination I have heard that made any sense.
I have a 1-12" twist 270 southgate.
I called Nosler they told me they doubted if 130 accubonds would stabilize. They even suggested I rebarrel.
Barnes said nothing longer than their 110 gr. would work well.
JBM Ballistic stabilization calculator gave me some relief thinking I could stabilize 130 and 150 gr. Grand Slams and 130 gr. Partitions.
Then I read all of the guys who actually shoot these rifle say they work just fine.
I guess it is time to load up heavies and see for myself.
this is from Barnes site

http://www.barnesbullets.com/wp-cont...MagnumWeb1.pdf

When Wby build the 1/12 twist barrels they offered ammo for it in 130gr/150gr and later they switched to a 1/10 twist barrel that was 1973.

You might want to look at Hornady's manual #9 for the 270Wby they used a 1/12 twist barrel.
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  #18  
Old 02-18-2013, 07:37 AM
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Re: 270 weatherby bullet choice

Steven, you would have liked watching a bunch of guys at the 1000 yard range checking out our stuff. I had just built an 8.5 pound .300 Win. Mag. with a worn out 30" long Palma rifle barrel in .308 Win. That barrel was set back 2 inches then shortened to 26" long. It's 1:13 twist was shooting Sierra 180-gr. HPMK's about 3300 fps and shot MOA or better; not too bad considering the recoil it had before the bullet left the barrel.

None of them believed a 1:13 twist shooting 180's form a .300 Winnie would do that well. When I told them that bullet was spinning about 198,000 rpm out the muzzle. That same bullet leaving a .308 Win. 1:12 twist barrel at 2650 fps spun about 160,000 rpm and was a favorite long range load from M14NM's, some of them finally agreed it was probably spinning too fast and a 1:14 twist would have been better.

I'd called Nosler regarding an issue someone brought up about their bullets and rifling twists and their response was similar to what your said Barnes' was. There are some businesses in the shooting sports industry who lack understanding and knowledge of reality; others lead the way in what works best because they do.
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  #19  
Old 02-18-2013, 11:11 AM
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Location: greenwood, IN
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Re: 270 weatherby bullet choice

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Originally Posted by 150pilot View Post
The stability calculator is wonderful. Thank you! I have not yet fired this gun, it followed me home about 10 days ago. The 130 gr Bergers may well be worth a try.

Digger here is an attempt at pictures.

The scope is one I had never seen before. German optics made by Pecar Berlin a variable 3-7 and clear as a bell. This scope was over a hundred bucks in 1967 and came with a 30 year warranty. Sure beats the weaver I bought new for $10 about 1969.
is that rifle a MK. V with the nine locking lugs or built off the FN action (they did both in Europe)? I have not seen a Eropean built MK. V in several years, but had the chance to buy a blond stocked .257 mag once that was European built.

Don't bother with the 130 Hornaday SST's in that rifle! Won't take that kind of velocity. I found that 150 grain bullets worked best for me. The powder of choice (if you can even fined some) is AA3100. It's now out of production. The rifles prefer near max loads, and seriously don't like to be down loaded. Factory loaded 270 mag rounds shot a little under an inch in my rifle (Norma). The domestic brands don't shoot nearly as well.
gary
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  #20  
Old 02-18-2013, 11:34 AM
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Join Date: Jun 2012
Posts: 12
Re: 270 weatherby bullet choice

Gary the rifle is a(Southgate Mauser) I believe FN Mauser action. I like the rifle a lot.
I will try some 130 and 140 gr. Partitions and I will look for some 150 gr. Speer Grand slams. I agree that the sst would not be my first choice.
I have a box of 130 gr. Speer Hot-Core I want to play around with first.
I do not believe I would shoot them at a game animal cept a coyote or maybe a hog.

I am hoping it will stabilize the 140s and will become a go to rifle for deer and I would use the 150s for Elk on occasions where a lightweight rifle is appropriate.
Thanks
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  #21  
Old 02-18-2013, 11:40 AM
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Posts: 154
Re: 270 weatherby bullet choice

I shoot 140 grain accubond in my factory winchester 270WSM @3250 fps with 64.5 grains of IMR 4350 shoots 3/8" at 100 and under 1 MOA at 1000 I am not possitive but when I bought it they told me that is was a 1:12 twist
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