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Twist Rate 8 12"?

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#1 ·
I just bought a Tikka T3 Lite 223 rifle and looking at the PDF file it says the twist rate is 8, 12". My question is does that mean it has a twist rate of 1:8 every 12" or what? If it helps the barrel is 22 7/16" long. The reason I'm asking is because I was thinking of loading up some 80gr rounds for the 600 yard range.
 
#2 ·
Thumb:

I'd have to read it as you did. 80 grain bullets with the long profile may not stabilize but you can only be sure by trying. Remember it is the length not the weight that is used in the Greenhill formula to determine stability. So stout looking bullets stabilize in slower twist rate barrels than long slender bullets.

LDBennett
 
#3 ·
First I have to see what the Ogive is one the rifle and second but really not needed is to see if a round would fit in the magazine. I know they will not work in my AR-15's because the COAL is too long for the chamber but 77gr bullets work fine.
 
#4 ·
Thumb:

He is shooting a bolt gun that he can single load. OAL is no problem as long as the bullet does not engage the rifling when fully chambered. The actual OAL has to be determined with the bullet and gun in hand. When used in competition 80 gr bullets in AR's are normally single loaded, according to what I have read. My AR with a Lothar-Wathers Match Varmint barrel takes the Hornady 75 gr HPBT bullet and feeds reliably through the magazine. It is a one in 8 twist, according to the sales literature for the American Spirit Upper. The accuracy is excellent.

LDBennett
 
#5 ·
1:8 is one revolution in 8" and 1:12 is one rev in 12". Lot to do with harmonics. I relate my relative understanding of harmonics to radio waves having been in radio for decades. 80 grain likes 1:7 in some and 1:8 in others from what I've heard. But then again, some guns will defy all that and shoot what it likes best that is different weight. Some times it will not shoot well at 1oo yards but will stabilize out past that and shoot well at 300 yards. So I guess it all depends on what distance you are going to shoot at. Supposedly from articles I've read, if you find a good round at 300, it will make a good round further down range to a point where other factors mess with it. If you find a good round at 100, it may not be good down range in some case. Just have to experiment.
 
#6 ·
OK, I found the answer on Tikka's website in the FAQ section, they say mine has a 1:8 twist so I'll start off with the 80gr bullets(if they fit) and if they don't work I'll start working down until I find a good load.
 
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