PP Bullets in a Tube Magazine Rifle?

[bruce moulds]

don,
the bumpup problem is due to the progressive burning of smokeless.
black goes instantly to peak pressure probably before the bullet starts to move or just after.
the bullet goes further before peak pressure with smokeless and gas can start leaking while this is happening.
groove diameter bullets help here, as there is a quicker seal.
the issues here are several.
one is that the rifle is a repeater, complicating fouling control.
this not only requires plenty of lube, but the right lube, which might mean different lube for different seasons.
if using smokeless the fouling issue goes away. duplex could also be considered.
with smokeless, groove diameter bullets would help.
as mentioned feeding from the mag is a potential issue unless the patch is fully in the case.
you did no hear this from me, but a greaser would seem to be the obvious choice, even with duplex.
accurate makes some good designs in many calibres for this type if application, but not sure of this calibre.
single shots make life a lot simpler. you can wipe, blowtube, breech seat, seat bore diameter bullets way out in the rifling etc etc.
keep safe,
bruce.