My response is simply because of my exposure to literally hundreds of cantilever slug barrelled Mossbergs over the past three years. This is a comment on the current production not the older models.
In as few words as possible :
The barrels are more than accurate enough for what the average hunter can expect in a pump SLUG gun.
However, all barrels examined showed a misalignment of scope bases (front to rear) on the cantilever mounts.The average windage is so compromised that the scope they provide (albeit cheap) usually bottoms out before you get a proper correction.
The scope is just not pointed in the same direction as the barrel. You can actually see it. Flipping the mounts does not always work.
I have repeatedly called them to no avail. It is a simple fix.They just keep producing these combos by the thousands and a lot of people are getting very frustrated/angry trying to sight them in. A damn expensive process as well if you are not aware of the deviation. .
Mossbergs from four large retailers all have shown this "quirk".
If you try to use conventional tools to bore sight it will lie to you and usually put you laterally 4 to 5 ft to the right of the target. Everybody who has had these bore sighted by the retailers has them shooting off in the next county until they undergo some serious realignment. They usually hit 4 ft to the right at 50yds.
Come on guys your barrels are fine. You just need a little better QC.
Pull one off the line and try it. You are doing yourself a disservice if you don't.
And yes, Roger is a nice guy when you call !
P.S. (I have and do own Mossbergs and a Mossberg barrel for an 870 Rem. The Rem. aftermarket barrel is phenomenally accurate . I have yet to shoot my own 930 ) . That being said they are still a great value.