Quote Originally Posted by Weevie View Post
Richard, there is one thing that you don't seem to have taken into account and that's the different stabilisation methods of pellets versus bullets.

Pellets are by and large (boat-tailed bullet type designs) have drag stabilisation as a large component of the total stabilisation (as the Cardews showed). Spin does come into it or we'd all be shooting smooth bores but drag stabilisation is very important. Needless to say I'd expect that to be a significant factor in the differences between a bullet and a diablo shaped pellet.

The effect of the different shapes on the wind's effects has got to be a factor too.

I don't think you can compare pellets to bullets. Especially when the bullets are being shoved along at 4000 fps!
Hi Weevie

All fair points, however if a drag stabilised diablo will stay stable at 550fps at 50 yards from a legal limit gun, what physical condition would cause it to become unstable from an FAC gun giving say 550fps at 100 yards?

As long as you stay inside the speed of sound then I cant see a reason (that translates across from firearms where much more is written) why it would suddenly deviate from its planned course.

Now to increase BC it may be necessary to move to longer heavier projectiles which may (or may not) benefit from a faster rifling twist?

I think the answers here may well be along different lines to what's accepted at 50 yards, for example three combinations shooting 1/2" groups at 50 yards may very well produce wildly differing groups at 100 much as with rifle cartridges.

I dont have the answer but I'm sure it doesn't reside with any one individual messiah more a reasoned (or lucky) choice of rifle and projectile in optimum conditions which will probably take much experimentation.

That said unless anyone can explain how a 550fps airgun pellet can become suddenly wildly unstable past a certain distance regardless of the speed at which it was launched I can only conclude a 1" group at 100 must be possible with the right barrel, twist and projectile.

If anyone has this information please let me know and save me hours of agonising

Richard