Taper

Thanks fellas, I wasn't sure, but it makes sense that its easier to load.

Which is more accurate; breech seated cylindrical or tapered bullets? It depends . . . IMO.
Both of my Ballard .32-40s have a long leade into the rifling (.5 degree included). One rifle is a dedicated bench rest rifle, the other offhand. Both consistently deliver slightly better accuracy with bullets that have cylindrical bearing bands (groove diameter) with the two base bearing bands being .001 over groove diameter. I have done lots of shooting with tapered bullets (bore diameter tapered to .001 over groove diameter) in those rifles and the cylinder is always most accurate. NOW . . . with the typical leade of most rifle chambers, groove diameter bullets are difficult or nearly impossible to seat. The long leade of my rifles makes seating stiff but any type of seater that gives a mechanical advantage will seat them with 1:20 to 1:16 lead/tin alloys.
There is no magic to it, your bullet needs to fit the way your rifle is chambered and the leade into the rifling. Do a chamber cast and take measurements before buying a bullet mold. 
This is MY experience (over 20 years with these two rifles) with breech seating and shooting .32-40 Schuetzen rifles, your mileage may vary 

I shot straight walled bullets .002" wider than my groove-to-groove barrel diameter using 20:1 lead:tin alloy using a Weber seater.
My base band is almost fully engraved by the lands. 
I have never had a problem breech seating my bullets and accuracy has been exceptionally good.
MY RKS barrel has a continuous choke of .0004" over the length of the barrel which also improves accuracy preventing gas cutting around the bullet.

.323 diameter straight wall Paul Jones spitzer bullets in a .321 groove-to-groove RKS barrel.