Bob La Londe fired this volley in news:b589d4bf-
:

It could be design (pocket vs jet) or some other
factor like the material its made out of.



I think its the concentricity and smoothness of the bore. The gas has got
to get up to almost unimaginable rotations per minute inside there for the
differential to be very high. Any minor defect in the walls, or any out-
of-round condition would disturb the flow.

LLoyd