Twist Rate for .243 WSSM barrel
What would be the best twist rate to push 100 grain bullets at factory ballistics in .243 WSSM. Thanks, Mike
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1:10,.... or 1:9 if a custom maker offers that twist 0 -
Thank you. Now I have a decision to make.-- Mike 0 -
Mike,,
Historically, the primary manufacturers have used anything from 1:14" to 1:9" depending on the era and in one case, a stupid mistake.
Twist rate is based on the length of the bullet and to a slightly lessor extent the length of the bullet bearing surface. Obviously most us aren't going to run around measuring bullets let alone bearing surfaces in a gunstore so we have to use more generic parameters to get close.
Determine what type of bullets you want to use and then look for the twist rates that will be optimum for those bullets. The longer the bullet the faster the twist rate. So, if you're looking into target shooting at long range, the VLD's need a 1:8" of even 1:7" twist. If your primary concern is hunting with the 100 gr. bullets such as you ask about above, the consensus is a slightly faster 1:9" to cover the possibility of using a few of the heavier bullets that are a bit longer. In some cases this will prevent keyholing or oblong hits at the target. Besides, this little bit of additional twist won't make your accurcy suffer, it merely expands the number and style of bullets that can be used in your rifle.
Some suggestions:
http://sst.benchrest.com/shilentwist.html
http://www.riflebarrels.com/products/caliber_twist_rates.htm
Best.0 -
according to rcbs the 9.1 is the minumum twist for 100gr bullets if you want to go to the popular 107gr that would be 8.5 but for 75gr bullets for varmits you would need 13 this would give you an idea of the twis rates that are needed for different bullets. 0
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