Advantage of chamfer on plain based boolits used for PP ?

[wmitty]

Is there any benefit from chamfering the base of plain based boolits used to make up paper patched loads? When I swage an as cast .311" boolit down to say .3015" to allow patching, I have noticed a fin of lead around the base which is sometimes formed. I felt this would be a problem, so I chucked the boolits in a cordless drill and touched the bases with a small file to remove the fin(s). Problem was, I couldn't get the chamfers the same size from one boolit to the next. Wondered if I was doing more damage than good. Anyone else run into this?

[Outpost75]

Bevel base prevents finning when throat diameter bullet is extruded into smaller diameter bore.

In paper patching is eases the base transition when twisting the patch closed at the base, making tears less likely in bullet seating.

[303Guy]

I was getting finning on firing as per Outpost75 so I introduced a bevel/rebate to the base and that problem went away. I tailless patch anyway so tearing is a problem for me. That small bevel/rebate is also handy for starting the boolit into the case mouth. I don't need to flair. The reason my bevel also has a rebate is that I must use a base plug in my mold and a sharp edge gets damaged too easily but a bevel is all I actually want.