re: #94 Stanley Sea

What the hell is that cannon that dude is holding?
What the hell is its purpose?

It looks like an larger than normal handguard, one that fits all around the barrel. The normal reason for that is to keep the hands and handguard away from a free-floating barrel, which means a barrel that does not come into contact with the handguard at all. The object of all this is to minimize external vibration’s effect upon the barrel and thereby increase accuracy. As supporting evidence I cite the ‘club’-type stock, which is larger than normal to help increase accuracy.

Basically that odd-looking rifle has been optimized for accuracy at a considerable cost in weight and bulk.

Edited. It’s been pointed out that the weapon in question is likely a bullpup shotgun.