Its a shotgun, not a rifle, but I am in love with this and am planning on making one.
"The Ultimate Survival Shotgun"
http://artofmanliness.com/2011/07/11/how-to-make-a-survival-shotgun/
The link leads to the Art of Manliness website detailing teh exact modifications they made to teh gun and what they are able to carry with them in survival supplies in just the gun itself. Its so sexy.
I had a Mossberg 500 with pistol grip for a while last year.
Couldn't get rid of it fast enough. The pistol grip is a retarded configuration for the Mossbergs.
Note that the action release is a small button to the rear of the trigger guard.
With a monte carlo, it is easily accessible with your middle finger. It's a great idea.
With the pistol grip, the grip gets in the way and you end up releasing your grip and fiddling with your fingernail to push it up.
That's the first dealbreaker.
The second is the safety. It's on the top of the receiver.
With the monte carlo, again, it's perfectly configured for your thumb to access it.
With the pistol grip, again, you're releasing your grip to go futz with the controls.
If you get one, by all means, don't put a pistol grip on it. If you need the pistol grip, go with a Remington 870, since the safety is more sensical, and the slide release is forward of the trigger guard and isn't obscured by the grip.