Can someone enlighten me on "barrel twist rates"?

[Pydpiper]

I was telling a buddy about my new Tikka .204, he asked about the twist rate and I have no idea what he is talking about.
Was this an option when I bought the rifle? I understand that there is always a twist rate, I mean is there one that is better than another? I figure Tikka would use what is optimum, am I wrong?

[WrzWaldo]

Twist rate is usually determined by the bullet/s you plan on shooting. Heavier bullets are usually longer and need a quicker spin to stabilize. In simplistic terms it's the length-to-diameter ratio that is used to determine the optimum twist rate for a given bullet. If you desire more info try a Google search for "barrel twist rate" and "greenhill formula".

If I'm not mistaking most all factory 204 Rugers come with a 1:12 twist rate.

Have fun!

WW

[Arizona Hunter]

WRZ, good answer. My Howa 1500 has the 1-12 twist. Works perfectly for 32 & 40 gr. V-Max and Sierra 39's. Have not tried the Hornady 45 spire point but my friends .204 with a 1-12 does the job right.

[Super 91]

One thing that I liked about the Les Baer Super Varmit in .204 was that it has a 1:10 twist. Seems 1:12 can be a little sensative to bullet weighing 40 grains or more. 39-40 seems to be the threshold. Not a golden rule, as some rifles do just fine, well, many do. But that seems to be the consensus wherever I go.

[Bayou City Boy]

To keep things in proper perspective, as WzW mentioned, barrel twist rate determines the length of bullet a rifle will effectively stabilize.

The longer a bullet is - and a bullet is nothing more than a gyro in effect - the more spin it requires to stabilize it in flight. It generally follows that longer bullets generally weigh more, but total bullet weight is not a real factor in barrel twist determination.

I had swage 20 caliber bullets and can make a relativley short 43 grain bullet that shoots fine in a 12" twist barrel. Conversely, I can make a long 35 grain bullet that is well balanced by bullet standards that will not stabilize when fired through a 12" twist barrel. The difference is bullet length and not bullet weight.

And contrarty to what some folks say, the amount of bearing surface a bullet has is not a factor in barrel twist. A long VLD bullet generally has a very short bearing surface but a long overall length which will require a fast twist barrel to stabilize the bullet.

Conversely, a hunting bullet in the same caliber and weighing roughly the same weight will generally have a relatively long bearing surface but an overall length that is much shorter than a VLD bullet, and the hunting bullet does not require a fast twist barrel to stabilize it.

The overall bullet lenght is the key....

-BCB

[Big_Bullseye]

One thing that I liked about the Les Baer Super Varmit in .204 was that it has a 1:10 twist. Seems 1:12 can be a little sensative to bullet weighing 40 grains or more. 39-40 seems to be the threshold. Not a golden rule, as some rifles do just fine, well, many do. But that seems to be the consensus wherever I go.

My Noveske AR204 w/ a 24" barrel is also a 1:10 and that was attractive to me as well in case I wanted to shoot the heavier projectiles. Haven't had it long enough to test many loads but it really likes the 32 grainers...

I understand the basis of twist rate and bullet stabilization and could not add anything that these guys haven't already. But listen to these experts if you want to really understand it in detail