What Barrel Length and Twist for a 270WSM Build

alcesgigas

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you’ve done this? what can you share?
Shooting & hunting with the 270 Winchester since '66 and beginning in 2012 shooting an edge and then two forms of Ackley improved 338s... The present is 1:9.5-1:8 twist and sends 256 gn Flatlines out the spout at 3410 I've become rather partial to gain twist and monoliths. Just prior to discovering this thread I remarked to a friend--and participant here also--that If I was to replace my 270 barrel It would be either a 26" lt. varmint 1:9.5 or 1:9 - 1:7.5. I shoot only copper; Barnes since the '60s and others including the already mentioned Flatlines, Badlands Super Dozers, Cutting Edge, etc. Aside from actual hands on experience all that was preceeded by research. The latter continues obviously.
 

Full Curl

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So many GREAT replies guys!!! Too many to quote or thank individually. THANK YOU ALL!!!

I'm a hunter first and LR shooter second. Some of you guys would probably run circles around me at the range. From everything I've read on here I'm leaning towards a 24" 1:8. I may call a couple barrel manufactures to get some more insight and will definitely be having a couple discussions with my builder. Thank you again for all the great information!!

I've read where some guys will buy their own reamer for a rebarrel and then just keep it for the future. It took me over 10 years to shoot the current factory barrel out and I would expect the same for my next barrel. Would it make any sense for me to buy my own reamer? Can load development be expected to be quicker from one barrel to the next if the same reamer is used? I'm sure it may need to be tweaked, but would it negate starting from scratch??
 

Stockbroker

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I've read where some guys will buy their own reamer for a rebarrel and then just keep it for the future. It took me over 10 years to shoot the current factory barrel out and I would expect the same for my next barrel. Would it make any sense for me to buy my own reamer? Can load development be expected to be quicker from one barrel to the next if the same reamer is used? I'm sure it may need to be tweaked, but would it negate starting from scratch??
A custom reamer could be practical to own, to avoid needing one ground to a custom spec more than once.
If the reamer is cutting a standard SAAMI spec chamber, don’t think you’ll find it making any difference.
Betting by the time you wear out another good barrel, you’ll know what you like for brass, bullets, powder...load workup should be a piece of cake.
 

Eric Alexander

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Mar 30, 2015
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The gain twist is what interests me. i am building a .270. Straight up simple 270. The barrel is 26” and I had decided on a 1/8 twist and planned on165 ablr and 155 Hammer Hunters. What persuaded you to go with gain twist? Less resistance at beginning for acceleration? Start at 10 increase to 8? Is there a downside to this a. approach?
 

Raudy707

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The gain twist is what interests me. i am building a .270. Straight up simple 270. The barrel is 26” and I had decided on a 1/8 twist and planned on165 ablr and 155 Hammer Hunters. What persuaded you to go with gain twist? Less resistance at beginning for acceleration? Start at 10 increase to 8? Is there a downside to this a. approach?
I'm thinking of doing the same thing with my Grandpa's Sako L61. For sentimental reasons I've been keeping it OEM. But man if it was 1:8 twist, it would be amazing. He shot it a lot since he purchased it in 1970 and the accuracy is fading. So I'm itching to throw a new barrel on the old gal and make it a new improved version. He's passed on and I'm sure would want me to keep hunting with it so this thread has all but convinced me to go for it. Should be awesome!
 

SSG Graybush

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Handicapping a cartridge to stay in a short action is counterintuitive nowadays. There's better ways to save 2oz
Yes shooting the 170 EH out of a LA would be the best LR performance you could get because of the bc efficiency but the OP has a SA to rebarrel. So the best choice for him is to go 9T.
 

alcesgigas

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Bettles Field, AK
The gain twist is what interests me. i am building a .270. Straight up simple 270. The barrel is 26” and I had decided on a 1/8 twist and planned on165 ablr and 155 Hammer Hunters. What persuaded you to go with gain twist? Less resistance at beginning for acceleration? Start at 10 increase to 8? Is there a downside to this a. approach?
Look into the history of gain twist as I have and you'll be happy--and "you can thank me later" as oft said these days. Think you're right on the "less is more" theory--that too is historic, but as yet unproven. The only downsides I've found with GTs remains their cost and wait time. And those are not absolutes. I think you'll be very happy with your choice; its been mine for a lifetime with double digits for black bear, whitetails, sitka blacktails, moose, and caribou. The only grizzlies were problem bears (2) and those were stopped with my 375. However, I'd not hesitate to hunt grizz with my 270. I've depended on it to eat.
 

Full Curl

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Rifle is at my smith now and I have to decide on barrel contour to order the barrel. As stated before, I'm going with a 24" 8:1. This is going to be a reasonably lightweight hunting rifle. Thinking a Bartlein 3b or a 3. The current 24" stock barrel hits the scale at 2 pounds 12.4 ounces and I know the 3b and probably the 3 will be heavier, but I'm not sure how much. Any recommendations or am I splitting hairs here between a 3 and 3b? Thanks!!
 

WHITEBULL

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Apr 26, 2015
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You should be good. I went with a fluted #5 26" and it added close to 2 lbs from stock 24".
 
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