twist rates

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westernsky
Posts: 56
Joined: Mon May 28, 2012 8:24 pm
Location: toodyay WA

twist rates

#1 Postby westernsky » Sun Jan 20, 2013 11:43 am

g'day all,
ive just been on the sierra website looking for 30 cal projys, and it seems that the side note they had on the 210gr and 240gr matchkings about minimum twist rates is gone. does anyone know if this is because they have been revised and they have realised these bullets no longer require the faster rates to be stable?
i have a 1 in 12 twist and would love to use the higher bc 240gr or at least the 210gr

happy shooting
theres no such thing as too many rifles!

westernsky
Posts: 56
Joined: Mon May 28, 2012 8:24 pm
Location: toodyay WA

#2 Postby westernsky » Sun Jan 20, 2013 11:52 am

forget that, must have been a glitch in my internet, when i retried it showed up!
on another note however, have they put a limit on the twist rate due to the expected mv being very low out of say, a 308win or similar, whereas if the mv was much higher, in the region of 2800 to 3000 fps would the increased rpm be enough to stabilise the heavier and longer bullets?

any thoughts would be much appreciated

happy shooting
theres no such thing as too many rifles!

bsouthernau
Posts: 696
Joined: Sun Mar 11, 2012 4:31 pm

#3 Postby bsouthernau » Mon Jan 21, 2013 6:57 am

Hornady claim that their 225gr BTHP Match will stabilise in a 1:12

Barry

Brad Y
Posts: 2181
Joined: Fri Jun 26, 2009 8:21 pm

#4 Postby Brad Y » Mon Jan 21, 2013 8:39 am

Surely that must be a typo, or at least it would stabilise in a 338 lapua necked down to 30 cal.

From reading alot of the FTR stuff overseas, 1:12 you can use up to about a 175gr-185gr pill

bsouthernau
Posts: 696
Joined: Sun Mar 11, 2012 4:31 pm

#5 Postby bsouthernau » Mon Jan 21, 2013 2:34 pm

Brad Y wrote:Surely that must be a typo, or at least it would stabilise in a 338 lapua necked down to 30 cal.

From reading alot of the FTR stuff overseas, 1:12 you can use up to about a 175gr-185gr pill


It surprised me too Brad. I wrote to them and asked as I feared my 1:10s that I shoot the 208A-Max and 210 Sierra MK in mightn't be fast enough. The 225 is longer than both of those but that was their reply. Haven't found time to do any exerimenting myself.

Barry

westernsky
Posts: 56
Joined: Mon May 28, 2012 8:24 pm
Location: toodyay WA

#6 Postby westernsky » Fri Jan 25, 2013 11:54 am

just ordered the 225's so i will keep you guys posted on how they go. hopefully hornady are right!
theres no such thing as too many rifles!

Brad Y
Posts: 2181
Joined: Fri Jun 26, 2009 8:21 pm

#7 Postby Brad Y » Fri Jan 25, 2013 12:07 pm

Im trying the 168 amax in a 12 twist remington factory barrel on sunday. If they keyhole (which im not expecting) then I would say your ones wouldnt be any good.

westernsky
Posts: 56
Joined: Mon May 28, 2012 8:24 pm
Location: toodyay WA

#8 Postby westernsky » Fri Jan 25, 2013 12:43 pm

guess i will have to see as theyve been ordered. 168's for me would be way too light, mv would be somewhere near 3500 im guessing.
i was going to run the 200gn sierras but the heavier the better for my cartridge.
theres no such thing as too many rifles!

Brad Y
Posts: 2181
Joined: Fri Jun 26, 2009 8:21 pm

#9 Postby Brad Y » Fri Jan 25, 2013 1:06 pm

Apparently Wurgabup are going to run FO for thier prize shoot- are you going to come down and have a go?

westernsky
Posts: 56
Joined: Mon May 28, 2012 8:24 pm
Location: toodyay WA

#10 Postby westernsky » Sat Jan 26, 2013 9:57 am

when and where? if i have my load sorted ill be there for sure
theres no such thing as too many rifles!


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