I will have the Grandfather owner.I have one of those Mossberg Bolt Action .410 that I am saving for my grandchildren. I had one when I was very young, which was a long time ago, bought this one in perfect condition on Rimfire Central a few years ago. I have used 2 1/2" and 3" shells with different shot. Actually I think 6's are probably best all round for most small game and birds. Does your .410 have the adjustable choke?
I'm not sure what my Model Number is but the gun is the one without the plastic finger piece on the grip. These shotguns are nothing rare or costly but they do work very well and are great to start out children. I like to shoot it at doves too, actually hit one every now and then.