You people who like the pistol grips and the saiga shotguns go ahead and use them. And when the prosecuting attorney flashes it to the jury and you end up in jail I'll send you a nice b-day card (on my b-day, not yours. I'll make sure it has a pic of me at a beach or something).
Get yourself an Rem 870 Express (with an 18" slug barrel), keep it bone stock, learn how to use it and then pray you never need it.
Why take the chance with the 870? Great, great grandaddie's flintlock should be all you need.