Quick question I'm looking to buy a Tikka in 270wsn. The specs say it has 11" rate of twist. What does this mean, is there a difference in different rifles and how does this effect speed/accuracy???

It means that, as the bullet travels down the bore, it is rotated once in every 11" of travel.

The significance of this is that rate of twist and the bullet length and shape are combined to arrive at the stability factor of the bullet.

For the average hunter it means that you should choose bullets that will give a stability factor of better than about 1.2 at impact.

For a 1:11" twist 270cal this means that bullets should not exceed 1.18" in length, regardless of what they weigh.

If the bullet has a stability factor of higher than 1, hunting accuracy requirement is not affected and twist rate does not affect speed. If you shoot bench or long range competitions, twist rate becomes important.

BC300winguy, simply put it is what Gerard said, the rate is how many 'turns' you get in so many inches. Practically, you need a little faster spin (lower # e.g. 1/8 vs 1/11) for a heavier bullet.

Gerard, that is a helpful reply. Is there a source for the specs that is simple for us non bullet manufacturing tyes? It's early, and I haven't finished my coffee, so I am not easily seeing the math represented by your info--it's probably real obvious--I haven't written it down and tried to pencil it out, but I'd like to know how it works.

Fish,
The easiest way to do this is to download a zip file from our site. It is a very useful bit of software put together by JM and GC Knight. It is based on the McGyro program that was done by RL McCoy. It installs quickly and is largely self explanatory to use. It is in two parts, WinLoad and WinGyro. Use the WinGyro part. Go here and click on the fifth picture down in the right hand column to open the download box. If you or anyone else need help with entering the parameters in the program, just let me know.

Here is a pics of my two Tikka T3 LS 270WSM with a Leupold VX3 4.5-14x40 BC reticle, the other a silver VX3 3.5-10x40 BC reticle (wife's rifle). Incredible shooters with 140gr Accubonds.

You will love your Tikka T3 in 270WSM. I just found a gently used Sako m75 SS 270WSM that I just may have to buy.

Gerard, thanks much for that. I will tweak around a bit and see what I need some help with!

Regards--Don