.338 WM twist rate

MagnumManiac

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Feb 25, 2008
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A 10” twist is perfect for all bullets up to and including 300g conventional cup and core.
If going to a mono, then a 9” twist is a better option.
I have 338’s with both twists and the lighter bullets aren’t phased by the faster twist at all.

Cheers.
 

FEENIX

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My next build is going to be a .338 WM. What is the best twist rate for 225-250 grain high BC bullets? Thanks
I have a 1:10" twist on my .338 WM, and as others have noted, it will serve you well for the majority of the bullets. "I" found that 225 NAB (1.45" OAL) is about the max bullet weight and OAL for mine. Some of the high BC bullets, esp. the monos, are long, i.e., Berger 250 EH is 1.67", BD2 225 is 1.68", BD2 250 is 1.873" and might be too long for the .338 WM's COAL, unless your action/set-up has room for a longer COAL. Good luck!
 

daneoslick

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missouri
hey guys i'm new to this but i have a 338 LM rifle , barrel twist 1:9.25 i run a 285 grain projectile but i was wondering if its possible to use a 300 grain berger OTM is that a ideal barrel twist for that grain bullet?

thanks
 

L.Sherm

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hey guys i'm new to this but i have a 338 LM rifle , barrel twist 1:9.25 i run a 285 grain projectile but i was wondering if its possible to use a 300 grain berger OTM is that a ideal barrel twist for that grain bullet?

thanks
You will be fine but Bergers twist Calculator will answer your question too
 

daneoslick

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missouri
I did use the calculator it gave me a reading of 4.12 from what I’ve read Thats “over stabilization” may cause issues so I’m not sure lol
 

L.Sherm

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I did use the calculator it gave me a reading of 4.12 from what I’ve read Thats “over stabilization” may cause issues so I’m not sure lol
I think you put in a wrong number.
I did this for giggles
 

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L.Sherm

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So in other words SG 2.03 would be ok?
Its little higher than I like but I think you will be fine. In all likelihood your SG will be little lower i dont think you will be pushing the 300 at 3250
Don't know if you have any other choice other than a mono.
Theres only one way to find out.
 
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