Polygonal barrel

[bucketboy]

They're not much good in anything...

Good point, well put!

[Airrepman]

More accurate than std barrels

[RichardinDorset]

The one on my sub 12 HW100 was crap.

[ballisticboy]

In terms of pellet flight there is no difference between a polygonal barrel and a rifled barrel, it is all down to the twist rates. I showed the effect of twist rates on pellet dispersion in a thread on the AGF which suggested there was a range of twist rates which gave the lowest dispersion but it was only for one pellet design with one dispersion driver.
As for different pellets requiring different twist rates like bullets it is not the bullet mass which is the deciding factor, it is the bullet length. If you had two bullets of identical shape, one of which is made of steel and one made of tungsten they would both require the same twist rate for stability despite one being more than twice as heavy as the other. The reason why heavier bullets tend to need higher twist rates than light weight ones is because they need to be longer to have the weight in the same diameter. Making them longer increases the aerodynamic overturning moments and changes the ratio of the moments of inertia leading to higher twist rates being required. This does not happen with pellets as the pellet is already aerodynamically stable so making it longer for a heavy pellet only tends to make it more aerodynamically stable. If the heavy pellet is the same size as the light weight one and only gets the greater weight by being more solid the aerodynamic moments will tend to decrease which may increase the gyroscopic stability with the same twist rate, so again a change in twist rate will have little effect.
If pellets were made bullet shaped then it would be a different story.

[buttloaves]

So no advantage sub 12fpe, more likely a disadvantage, id still like one though if only for the novelty factor maybe in .20 whats more novel than that.

[DCL_dave]

Is polygonal the same as polygrooved?...my old .177cal RH91 had a polygrooved barrel fitted as standard.