Brownells Brownells Brownells 75th Anniversary - A Shooting Heritage

Shotgun Chronicles Part II

Shotgun Chronicles Part II
From point and shoot to aimed fire
By Joe D'Alessandro

 

Part I concluded with my Mossberg Ulti-Mag 835 now sporting a 24" rifled slug barrel with adjustable sights and an extended magazine that added three rounds of magazine capacity. Its overall length had been reduced to 44-1/4" with weight held at 7-1/2 lbs. In the world of lever action carbines, that is probably a tad long and heavy, but in the world of shotguns with magnum-length actions, it is almost tiny.

The Long & Short of Selecting A Replacement Stock

The Mossberg's synthetic stock no doubt contributed to the modest cost of the firearm. However, the molded-in tab for a swivel mount is fragile, the cheese grater sharp checkering is rough on the hands, and the shallow radius sweep of the pistol grip is good for point-and-shoot shotgunning but provides little hand support for aimed fire. Fortunately, there are lots of inexpensive aftermarket solutions to improve the stock situation.
A little caution needs to be exercised in selecting replacement products. For the most part, buttstocks that fit Mossberg's popular Model 500 will fit the Model 835, too. But this interchangeability does not carry through to the forearm. The Model 835 is a magnum gun and has a longer action length than the 500 series, and it has different-length action slide tubes. Early guns have a 7-3/4" tube, while newer guns have a 6-3/4" tube.

Consequently, replacement stock sets made for this gun may include - or require the purchase of - a special action tube nut to adapt the forend to the shorter action slide tube. The easiest thing to do is pull the barrel, a five minute task, and measure the slide tube as shown below. With the action tube nut in place the assembly may measure a bit longer than 6-3/4", but not by much – it'll still be closer to 6-3/4" than 7-3/4".
My gun has a short action slide tube, so the selection was a Hogue Overmolded buttstock/forend set (#408-000-059) and the necessary forend adapter nut (#408-000-069). The Hogue stock offers some enhancements over the factory stock: a higher comb, a good resilient recoil pad, a tighter pistol grip radius, and stippled soft overmolded rubber at the grip area for a good hold without the Cheese Grater Effect. A sturdy, steel sling swivel stud replaces the factory stock's molded in mount. The forearm is also overmolded and has a more rounded cross section, so it's more comfortable to use. The improvements are both functional and aesthetic - and inexpensive.
Of course, before I started working, I double-checked the gun, magazine, and chamber, to ensure it was unloaded before it started handling it. Disassembly and assembly are covered by the Mossberg Owner's Manual, but the manual is a little skimpy on text and illustration. Sometimes it helps to know where parts were before gravity rearranges them, so here's some help.

Forend Removal: Be Forearmed (With Knowledge)
Our forend story begins with the gun's slide pulled all the way back, then advanced forward until the bolt face is about halfway forward in the ejection port. Then the magazine cap and barrel can be removed.
The key is to leave the safety in the "ON" position during this process, so it will not physically interfere with disassembly/assembly of the elevator. I also removed the buttstock before working on the forend installation to make the gun easier to handle on the bench - and to prevent the overmolded stock from grabbing the aft edge of the trigger assembly and preventing its removal. Ask me how I know...

With the gun laying belly up on the bench to keep parts from falling out during disassembly, a light tap with a 3/16" punch is all that is required to remove the single pin that retains the trigger assembly in the receiver (see arrow). The released trigger assembly is rotated, aft end first, out of position for removal.
If the gun has more than a few miles on its odometer, these parts might fall out of their respective channels when the trigger assembly is removed. If they didn't fall out on their own, now would be a good time to remove them. The interrupter is pinned to the receiver, and only the right side of the receiver (receiver right side up) has a pin hole and the end hooks curve in on both.
Move the slide about three-quarters stroke, until the bolt slide tabs line up in the cutouts in the side of the receiver. The bolt slide lifts straight up and out with virtually no resistance. Raise the elevator slightly, then push the bolt forward and out of the barrel opening of the receiver.
Raise the front of the elevator and pinch the elevator legs together to pull its locating pins out of the sides of the receiver. If the safety had been left in the "OFF" position, it would get in the way and make clearing the pins difficult. With the elevator out of the way, the forend is free to be pulled forward and out of the receiver.

This gets us a gutted receiver, more or less, that's ready for the new slide and adapter to be installed.

Reassembly is just the reverse of the disassembly sequence, with no majorproblem spots to deal with, though some patience helps a lot. For example, when inserting the new slide assembly, the arms on the action slide tube assembly will want to wander off in different directions. Then when you begin to feed the arms into the receiver, the right side will bump first in the receiver channel and it will have to be guided. As soon as the arms move another quarter inch, the left side will be the hang up. With a little finger pressure and patience, the reassembly task will be easy - except for this.

The original action slide tube assembly needs to be carried over to the new forend. The original action tube nut (on the right in this photo), is replaced with the Hogue adapter nut. Unfortunately, the action tube nut is recessed into the front of the forend and hangs onto the action tube for dear life.

 

Brownells carries a forend wrench (#080-777-004) for Mossberg 12 gauge shotguns. But because I rarely do shotgun projects and because I am always looking for excuses to fabricate parts and tools, I decided to make my own wrench. I also like to make tools from other tools - as long as they are very inexpensive tools.
In this case, a $3 discount store combination square was the organ donor. I laid the rule across the action tube nut, marked the span plus enough relief to clear the surrounding forend material, then I milled out a notch. Yes, I could have used a hacksaw and file, but it wouldn't have been as much fun. The tempered scale was left full length, as the excess extension made for a nifty handle with lots of mechanical advantage, and when I was done, I put the rule back into the square and placed both back on active duty.

But...The Stock? A New Buttstock!

An ordinary large screwdriver can be used to pull the stock bolt, but if it is stubborn, a ratchet wrench, extension bar and 1/2" shallow socket makes removal an easy task. The white plastic insert, bottom right in the photo, needs to be carried over to the new stock because it holds the shape of the stock so it won't compress inward under the recoil pad. The factory bolt passes through a thick steel washer and a lock washer.
Over the years, Mossberg has used a couple of different length bolts. So the new stock comes with a thin washer that can be substituted for the thick washer if enough thread doesn't protrude. The stock bolt should be tightened, but not to the extent it interferes with trigger assembly removal. Ask me how I know that happens.
The finished product should end up looking a bit like the installed stock above; great nonslip grip surface and much better radius for aimed fire. There's also the higher comb for a more natural sighting position, a more effective recoil pad, and a swivel stud that won't give out.

Conclusion

After getting the gun back together, I spent a little time at the range with some 3" 1 oz. and 1-3/8 oz. slug loads. The new stock geometry and recoil pad did a much better job of recoil management than the original stock, which seemed to provide very little dampening. The overmolded rubber surface was a lot easier on the hands, and the new furniture really upgraded the old Mossberg's appearance.
The new stock took the gun one step closer to where it needed to be for hunting season, leaving just a few more things to wrap. The extended magazine tube needed better support – there's just something worrisome about that much of a free-floating projection, cantilever design or not. A good shoot-and-carry sling is a necessity, and the receiver scope mount had outlived its usefulness. A faster sighting system for hunting in densely wooded area seemed essential for my needs. Until next time!...