First, the easy stuff, all of which is at the back of the shotgun. Here we see the Magpul M16 customizable grip, and the Midwest Industries adapters for pushbutton swivels for the M4 stock.
Due to the already long length-of-pull, I couldn't use the extended grip backstrap. Still, it seems to have a more comfortable shape. Also, although it doesn't apply to the Mossberg, Magpul redesigned the rubber base of the pistol grip storage compartment, allowing five rounds of 5.56mm to be stored there, rather than just three.
The rear swivel adapter goes through the horizontal slot in the back of the stock, and can be set up for either right or left handed use. The front adapter is quite ingenious, in that it's ambidextrous, slips on over the action tube when the stock is removed, and securely locks the round action tube nut in place. Even if you use plenty of Loctite and a special stock spanner, both of which I have, proper procedure requires the nut to be staked in place. This split adapter does just as good as staking, in my opinion, and provides a handy location for a single-point sling.
The grip and the sling swivels were easy. I received a bit more of a surprise when it came to installing a sight. The new straight-line stock configuration means the shooter's head is naturally higher up on the stock. Most sporting guns have a downward pitch on the stock so the eye lines up naturally with the low-mounted sights. Well, as with the M16, the sights now have to be mounted much higher.
I used a "surplus" Docter mini red-dot sight from a project that I have put on the back burner. Mounting it on that small piece of M1913 rail made it so low I couldn't even find the red dot.
Brownell's to the rescue, with a couple of $13 "extenders" that raised things 3/4 of an inch. Because the Docter is so small and short, I only needed one, as this shows. But I had the hunch two might be better.
Everything worked, but I wasn't happy with the looks. I decided to put the second extender on the rail, just for cosmetic purposes.
About then, I discovered that the two extenders cannot be butted together and have all the mounting screws line up. Each has a full-width "island" at each end, and I'd have to machine away half from each one so things would line up. Using a disk grinder and a surface plate, I spent a pleasant hour fitting the two extenders together until the fit as a single item.
I just had to exercise some patience, and a bit of water to cool the aluminum. It got too hot to hold after a couple of seconds of grinding otherwise. When I was done, the dimensions were correct, and the fit was almost airtight.
I could now put both extenders on a rail, and they would join up perfectly, enabling them to act as if there were one single piece.
So now things look a lot better, but I'm still not too happy with the tiny Docter sight sitting on a little platform high in the air.
So I will ponder about using some other sight that is bigger, and can fit the shotgun without the ad-libbed modifications I made. I may use the original long cantilever, even if I have to cut off some of the excess. But that's another installment for the future in the continuing series, "As the Mossberg Turns". I still have to come up with, perhaps, a new sling system, and some accessory shell carrier.
For some quick-and-dirty bolt-on accessories, this is becoming a major undertaking.