First, I am not a BR shooter, but rather an avid shooter/hunter. On the hunting threads, posters usually advocate for a faster twist rather than a slower. For example, 7.5-8" twists are "musts" on any 6.5mm rifle; 10" twists are "needed" on 35 calibers and 9.3x62; and anything slower than a 9" twist in a 7mm is going to leave you high and dry. Anyway, I wanted to ask the BR crowd about the following:

1) True or false: stability is governed by twist rate alone, and (forward) velocity is irrelevant to stability.

2) True or false: An overly fast twist accentuates (rotationally) the effect (on accuracy) of any imperfections in the bullet?

3) True or false: An overly fast twist increase copper fouling and reduced potential velocities (holding pressure constant).

4) True or false: the line between stable and unstable is very thin - stability is usually an all or nothing deal.

5) True or false: Air friction reduces the rate of bullet rotation during its trajectory.

TIA...

The answers are F, T, T, F, & T.

The questions are a little irrelevant though. It's a fact that certain bullets/calibers require a faster twist for stability than others. There are no doubt a myriad of factors affecting bullet stability that we have to take by faith since everything happens so fast. You want enough twist for the bullets you intend to use but not an excessive amount because, as in just about everything else, there are disadvantages to taking things to excess.

Bullet shape influences stability, so most of the twist recomendations are allowing for ALL bullets in the caliber. I would prefer to error on the side of too much twist, than not enough. The only time a minimum twist is usefull is in trying to shoot perfectly tiny groups or highly frangible bullets. A faster twist does increase pressure and reduce potential maximum velocity, but I don't feel it has anything to do with fouling(that is barrel specfic). Temps below 32* F will also affect stabilization, cold weather/dense air require more twist.