Yes, I can see how that would cause a problem, but I don't think it's tapered, it really doesn't look like it is... does anyone know for sure?

You got me there - what the **** are you talking about?

Seals are naturally tapered to make them more hydrodynamic in the water.

I think its related to this post...

http://www.locostbuilders.co.uk/viewthread.php?tid=172758

When I rebuilt my calipers the seals had a definate taper, with the thicker end facing down into the cylinder. Maybe you have been given the incorrect seals. HTH Ray

Spoke to bigg red, they said the seals are square-cut. I guess I must have nicked it (although it looks fine to me) when inserting the piston.