The gun weight itself is 6 lbs.
Yes
Do you mean ejecting?
Yes
Marlin recomends shooting Remington shells. I bought that same rifle and there was a coupon inside the box for $5 off your first box of shells from Remington. Remington now owns Marlin, so what else would Marlin recomend shooting?
The marlin model 990 was made to hold 18 rounds in its tube magazine.
Your marlin should hold 5 plus one in the chamber.
I have a marlin 55 12 Ga and Im wondering if it shoots 3" and 3 3/4" shells and if steel shots are recommended for the barrel?
mine holds 9.
Varies according to caliber.
You will have to tell us if they are loaded or empty, whether they are shotgun shells (and the gauge), rim fire or center fire and the caliber.
A marlin lever action 30-30 rifle can hold fife shells in the magazine and one in the chamber.
It's difficult to answer the question because gauge and caliber are two different things, and different shotgun shells have different types and numbers of projectiles.