Have been reading and asking several folks about this:
I have heard several different responses, the one that (so far) seems most logical, is that Marlin ran into an issue in the way that they ported, and it acutually created a hazard condition to anyone standing in close proximity to the rifle when fired.
The porting was not relieved and small bits of shrapnel could be pushed out the porting at a velocity high enough to imbed it in surfaces...
it also caused a non accurate rifle do to the fact that the bullet would then spin around its center of mass which may or may not be the center of the bullet..
Im NOT a gunsmith, and am just looking for info as to if I should get my factory ported marlin "re-ported"..
Any info as to if this is or is not the case would be appreciated prior to spending the $ to port it..