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View Full Version : Rem 700 R-5 mil spec 308, 1:11.25 twist



missloumudcat
03-08-2008, 06:49 PM
My question is about teh rate of twist. I normanlly shoot 168 grain pills in a 1:10. Would this rate of twist be OK for my 168s?
Thanks,

Jim

CWPINST
03-08-2008, 09:12 PM
Of course!!! A 12 twist will stabilize the 175 SMK, so a 11.25 is fine.

Louis Boyd
03-09-2008, 10:55 AM
The required twist rate depends on:
bullet weight
bullet length
bullet shape
mass distribution within the bullet
range (otherwise stable bullets may not be stable near the speed of sound)
velocity
air density
Air density gets lower with
lower barometric pressure
higher elevation
higher humidity
higher temperature

In my opinion the only way to know for certain that a barrel has the correct twist for a given bullet is to shoot some and measure the results. All of my shooting is at elevations over a mile (mostly 5400-5800 feet) in Arizona. Because of the low air density I shoot most accurately with considerably slower twist barrels than most bullet or barrel manufacturers recommend.

My loads would probably be horrible in a cold low elevation climate. I don't expect to ever find out.