7mm STW barrel twist

[camping1601]

I going to be replacing the barrel on my 700 in the future and want to start learning about twist to make a better informed decision. My primary want out of this gun is to shoot 140's for Deer, but I do want the option to load heavier bullet if needed.
Knowing my main purpose is to shoot 140's, with heavier as an option, what twist would be preferred?
Will be a 26" barrel.

 

[LaHunter]

My 7 rem mag (not STW) shot 160 grain Accubonds with a 9.5 twist great. I am currently getting it re barreled and I decided to go with a 9 twist with the new barrel to allow me the option of going a little heavier/longer if I wanted to in the future. My plan is to stay with the 160 grain Accubonds, however. I would discuss this with your gunsmith that will be installing your barrel along with calling the barrel maker and discussing with them too.

 

[100percent]

1:11 is optimal with the 140-150grain cup and core bullets running fast, from my experience. For longer bullets like the 150 swift scirocco and especially monolithics 1:9.5 is often necessary. For 175-195 Berger or longer you will need at least 1:9, preferably 1:8.5.
Their is such a disparity in length between the two bullet classes, it is difficult to meet in the middle so err on the side of caution with faster twist.

 

[General RE LEE]

I going to be replacing the barrel on my 700 in the future and want to start learning about twist to make a better informed decision. My primary want out of this gun is to shoot 140's for Deer, but I do want the option to load heavier bullet if needed.
Knowing my main purpose is to shoot 140's, with heavier as an option, what twist would be preferred?
Will be a 26" barrel.

I just inherited a 7mm STW. Is your barrel shot out?


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[ckleeves]

IMO I would narrow down exactly what bullets I really wanted to shoot and look at the required twist rates for them and not try a “one twist fits all” barrel. At STW speeds I think you could get into trouble with a fast twist and 140 class bullets depending on how fast you push them. I might be off on this so don’t take this as gospel but I think it’s Velocity X 720 / twist= RPM.

Lots of good articles out there on max rpm and over stabilizing bullets. Worth your time reading up and running some numbers before you order a barrel. It’s certainly possible to overtwist. I did it recently in fact.


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[doverpack12]

I have a 9 twist STW and shoot 143 hammer hunters. I’ve shot them to almost 3700 fps. I settled for 3350 and near bullet diameter hole accuracy all depends on my abilities that day. I’ve also shot 180 Berger’s, 175 partitions and lately messing with 195 Berger’s just for fun. All shoot better than I can

 

[Tumbleweed]

Here's a great tool. Start plugging in some bullets you're interested in with estimated velocity. See how much twist you actually need to achieve full b/c... not just enough for accuracy.

Twist Rate Stability Calculator

Our newly updated Twist Rate Stability Calculator not only tells you what your SG is, but it also lets you know if you are reaching your optimized BC.

bergerbullets.com

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[camping1601]

I just inherited a 7mm STW. Is your barrel shot out?


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No. Mines a rechambered 7mm mag that I'm building into a custom gun.

 

[JMDavies]

Following

 

[2five7]

What altitude do you shoot/hunt at? A 9 twist would allow for 140's up to 180's if your say 4000' or so ASL.

 

[camping1601]

2000' would be the norm for Deer.

 

[slm9s]

I think for a hunting rifle go with the fastest twist you'll likely need. Having a twist faster than optimal won't negatively accuracy much. Sure for a benchrest rig you need to run slower twist for the 140s. I'd twist it for the 180s, I'm sure it'll shoot the 140s great as well.

 

[Cahunter805]

Lots of info given above. I agree that I’d twist it 9 also. Will handle a wide variety of bullets well.
Interested in buying a custom 7STW?

 

[Bater]

9 twist for your needs

 

[camping1601]

Thanks for the input guys!