willtim
Well-Known Member
What is the optimum twist for all bullets in 338 WM? Thanks
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338 Win Mag twist
- Thread starter willtim
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HARPERC
Well-Known Member
"All bullets" the heavier mono's can require a 1-8".
My recollection is 1-10" being standard, which is fine for most of the weights most useful in the .338 Winchester. Especially cup and core.
My recollection is 1-10" being standard, which is fine for most of the weights most useful in the .338 Winchester. Especially cup and core.
What do you currently have one now, the barrel twist rate, and what bullets are you planning to use? The optimum twist is relative to a few factors, i.e., bullet weight/length. My .338 WM is a 1:10" twist and has loaded up to 250g NABs. However, the 225g NAB is the heaviest I would go because the .338 WM does not have the powder capacity to take advantage of the heavier bullets. The bottom line is to have the right barrel twist to properly stabilize (>1.5 SG) your bullet of choice.
I agree. Was not thinking when I made my last post. Further did not consider possible COAL limits. So use to setting things out where I have room to stretch bullet seating out getting the bt up into the neck. Gotta get my brain in gear!?!
willtim
Well-Known Member
I don't have a 338 WM but want to shoot 225-250 Accubonds.
mcdil
Well-Known Member
I would say that really depends on what you're doing with the rifle. If it is a more traditional mountain rifle or heavy woods rifle, the standard 1:10" is more than enough. In fact our current .338" Afterburner will work in a 1:11" twist, but that is more a function of the fact the nose can only be so long and still be SAAMI for some popular options in 338. This bullet is a freight train in the 338 WM at 200gr with a BC very similar to the 250gr AccuBond, maybe slightly superior. I have not shot both side by side off the radar yet, so that is off an estimate only at this point.
If you're trying to make a long range platform out of it, especially with monos, while the 338 Win Mag isn't your typical pick for something like that, a faster twist up to 1:9" can be done. I wouldn't consider it practical or ideal versus other options, but it would work. You would need to ensure there is clearance out the front of the case unless you plan to shoot only single shot from the beginning. The longer 338s have long noses. Having said that, it appears you're looking at AccuBonds specifically, and for that, I'd stick with 1:10" for sure.
If you're trying to make a long range platform out of it, especially with monos, while the 338 Win Mag isn't your typical pick for something like that, a faster twist up to 1:9" can be done. I wouldn't consider it practical or ideal versus other options, but it would work. You would need to ensure there is clearance out the front of the case unless you plan to shoot only single shot from the beginning. The longer 338s have long noses. Having said that, it appears you're looking at AccuBonds specifically, and for that, I'd stick with 1:10" for sure.
willtim
Well-Known Member
Proof makes a 338 barrel with a 9.4 twist. I think Bartlein will carbon wrap one in eight twist. I guess the real question is what are the downsides to going with a fast twist barrel?
HARPERC
Well-Known Member
Order time can at times be longer.
In a hunting rifle, with a moderate cartridge, probably none.
In a hunting rifle, with a moderate cartridge, probably none.
mcdil
Well-Known Member
I think it depends on the ranges you're considering, the bullets you plan to shoot (looks like 225-250 AccuBonds), and the rifle platform. Again, based on your desire for that specific AccuBond range of weights, a 1:10" offers no weaknesses and is best for the bullets in question. These bullets do well at reasonable ranges, but they're not long range specific bullets. They're more of an all arounder. I'm not sure where their threshold is for rpms, but that's always something to consider for cup and core bullets, their limits. However, I'd guess you're way far away from an issue there with your 1:9.4 you're looking at. A 1:8", may be fast enough to eliminate some common bullets from use. Not sure.
If using monos, spinning faster doesn't really come with significant weaknesses as long as you're staying above the transonic range (the transonic issue applies to cup and core too). If you're hunting with it, that really wouldn't be a consideration anyway and would be more of a target shooting consideration to stay away from overstabilization for proper "nose over" behavior when going through the transonic range. Significantly over spun bullets will experience additional spin drift in general. All good ballistic calculators account for this, but it is an additional consideration.
Truly not sure your overall intentions, but based on the cartridge and bullets chosen, if you're not going to go with a 1:10" (which is what I'd do knowing the only two data points you've discussed), I'd only go as low as a 1:9.4". That opens up some of the other options designed around the Lapua should you have the desire to try them at some point but not really penalize you for anything else.
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HARPERC
Well-Known Member
The .338 Winchester does very well with the 225 NAB. It shoots the 250's, but the 225's seem to be a better compromise.
It will shoot the old 300 grain RN pretty well, but would need to be for a specific use.
All 1-10".
It will shoot the old 300 grain RN pretty well, but would need to be for a specific use.
All 1-10".
mdmiller
Well-Known Member
My 338 WSM is a 1-9, it shoots 225's 3/8 holes at 100yds!!!
You will have to do your own test to see if the 225 and 250 NABs can withstand the 1:9.4" barrel twist. I think you should be OK. I have a 1:8" on my .338 NMI and most of the bullet I will be using recommends 1:9" and faster. Good luck!
sable tireur
Well-Known Member
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- Oct 8, 2010
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Here is some information regarding the factory rifles and their twist rates:
As stated, your choice of bullets and bullet construction will have a bearing on your rifle's twist rate. Generally speaking though a 1:10" will handle most common bullets. This does exclude some of the solids which might require a slightly faster twist.
There is a Badlands Super BD2 which will work in a 1:11" or faster twist. The Nosler 225 Accubond and the 225 E-Tip will work in this as well. I've had good results and success with all three.
I did use a factory Winchester for some testing and I stepped into the standard cup and core design bullets for the slightly slower twist rate.
My hunting rifle has a Bartlein 1:9.4" which is superb up through most 250 grain designs except for the much longer target solids. I see no reason to even entertain the use of 300 grain bullets in the .338 Win. Mag. Not enough powder.
Enjoy!
As stated, your choice of bullets and bullet construction will have a bearing on your rifle's twist rate. Generally speaking though a 1:10" will handle most common bullets. This does exclude some of the solids which might require a slightly faster twist.
There is a Badlands Super BD2 which will work in a 1:11" or faster twist. The Nosler 225 Accubond and the 225 E-Tip will work in this as well. I've had good results and success with all three.
I did use a factory Winchester for some testing and I stepped into the standard cup and core design bullets for the slightly slower twist rate.
My hunting rifle has a Bartlein 1:9.4" which is superb up through most 250 grain designs except for the much longer target solids. I see no reason to even entertain the use of 300 grain bullets in the .338 Win. Mag. Not enough powder.
Enjoy!
