My ULA does not have a vent liner and ignition with numerous powders is stellar. It also achieves a true head space on the rim of the primer and is about as sealed as one can get.

It also goes bang every time with a Harvester smooth black and a .451 bullet even with smokeless powder.

I attribute this to the breach plug design. The flash hole never seems to grow either. The same number of loads would have worn out at least 3-4 Savage vent liners in my Savages.