Designing the 2-diameter paper patch bullet.

[Distant Thunder]

Cap,

I have known a couple shooters who got good result with tapered bullets, I never got consistent results with them. To answer your question I think you have understand why bore diameter bulets shoot so well.

With a bore diameter the bullet is sitting almost fully in on the rifling and as a result, if it fits snug in the bore, is in as perfect alignment as you can possibly be before the powder is ignited. A DD bullet does the same but it fits the case mouth of a unsized grease groove chamber so that little or no sizing of the case mouth is necessary and the cartridge can be handled and chambered without the bullet falling out as long as care is taken.

A tapered bullet does bridge the difference in diameter between the case mouth and the bore like a DD bullet but does not have any length of the sides really supported by the rifling. There is really only one point of contact with a tapered bullet at the start of the rifling. It has to under go considerable change in shape to fill the resulting gaps when the powder lights up. Generally the less change in shape a bullet goes through the better the accuracy. I think tapered bullets are more likely to upset off center when they are fired and that result is flyers and inconsistent performance like I've experienced with them.

A DD PPB is the same as a bore diameter bullet except it fills the larger GG chamber area better with the larger base which helps reduce upsetting to fill that space when it's fired and then being forced down and engraved as it transitions into the rifling.

I hope that helps.