Im looking for a short shotgun to keep on my ATV for mainly Bear/other wildlife defense but I may take a pop at a grouse if I see one. This wont be my primary hunting gun but may get used for it every now and then.
Defense shotguns have discussed a lot on other threads and i'm not looking to reopen that
I have a narrow questionwhat is the right barrel length?
I think I've landed on getting an 870 so that's been solved
Ive seen as short as 8 inches but that only holds 2 +1 and i'm guessing that any bird shot will be useless.
My lean right now is 12 inches but the 14.5 seems pretty common?
Where is the sweet spot?
IMHO its a mistake to choose a pump shotgun with a barrel short enough that the support hand can reach beyond the muzzle. If you are using the gun in wet cold conditions, and find yourself in a stressful defensive shooting situation, its not inconceivable that your hand could slip off the slide and in front of the muzzle just as the gun fires. Apparently I'm not the only one to identify this problem as several manufacturers now provide devices to restrain the hand; either a short loop sling attached to the forend or a protrusion which acts as a hand stop at the font of the forend. If you insist on such a short gun, I would advise you install such a device, and if the gun has one, not to disable it.
Another problem with very short shotguns is a diminished magazine capacity. I don't think I would choose a barrel length which reduced the magazine capacity to less than 5 rounds. Having carried shotguns in the defensive roll for many years, I am of the opinion that a magazine capacity with more than 5 rounds is only a small advantage compared to the extra bulk and weight added to the gun, but a magazine capacity of less than 5 rounds can be a problem, at least physiologically.
A shotgun with a vertical magazine negates this concern, but the vertical magazine creates other problems. One problem is the ease by which the gun is carried at the balance. Another problem is the ability to conveniently exchange the type of shell in the magazine and in the chamber with another. You might for example carry the gun with a magazine full of slugs, but wish to fire a less lethal round or a load of birdshot, but unless its the subsequent round in the vertical magazine is of that type, it would be clumsy to drop the intended round through the ejection port, partially remove the magazine, close the action, seat the magazine, then aim and fire. With a tube magazine, the action can be opened enough that you can drop the intended shell into the ejection port without releasing the subsequent round in the magazine, then just close the action and fire. With little practice this can be accomplished without ever taking the butt out of your shoulder. An alternative method is to load the magazine one round short of capacity, then the selected round can simply be pushed into the magazine and the action cycled, ejecting the slug, and chambering the intended round.
Another consideration is the weight of the gun and it's balance. Weight dampens recoil, and balance allows the gun to carried easily and brought into action quickly. A 12 ga gun with a 12" barrel and two round magazine would be a handful to control in a dangerous situation when loaded with slugs or 3" buckshot, and is not as nicely balanced as a gun with 4 to 8 inches of additional barrel length. A basic pump shotgun (500, 590, or 870) with a 16", 18" or 20" barrel is a better bet. Install a butt with an adjustable length of pull, like Magpul's SGA, or modify the factory stock to fit, and install an XS big dot bead or rifle sights, and an inch and a quarter wide sling. A side saddle is a nice touch, and provides more, or different rounds than are carried in the magazine.
A 20" shotgun is a convenient length . . .
SGA stock is easily adjusted for LOP . . .
