Side project: Shortening a stock and epoxy fill

General Firearms Shotguns
1

This is simple and straightforward. I wanted a strong, heavier synthetic stock on a Remington 870 project. All the synthetic stocks I have handled have been really thin walled and minimal in actual volume of material, making them quite light. This is nice if you’re trying to save weight but it also shifts the weight bias forward. I decided on the Speedfeed II series stock, which is a thick-walled synthetic stock with some heft to it. I also wanted a 13" LOP and these only came in 14" LOPs. The only solution was to hack it down.

This ended up only taking about 30 minutes in total from receiving the stock to having a shortened, epoxy-filled stock ready for a grind-to-fit recoil pad. I suspect once I get it mounted onto my project 870, the weight balance will feel quite nice, and the small weight penalty will be worth it if the center of balance shifts rearwards. I didn’t photo document the cutting of my stock, but the steps go:

[ul]
[li]Mark 1" off stock to drop it from 14" LOP to 13" LOP (with 1" recoil pad in that calculation)
[/li][li]Scribe line with my height gage all the way around the stock
[/li][li]Cut with hacksaw, staying at least 1/16" away from the scribe line. Check often because hacksaws don’t like to cut straight.
[/li][li]File, then sand end of stock to scribe line.
[/li][li]10 minutes, done!
[/li][/ul]

Here is the stock with the remnant 1" chunk that was cut off. The Speedfeed stock I received was poorly manufactured. I believe others have voiced this opinion of poor finish on the new Speedfeed stocks since Safariland took over. Lots of flashing on the stocks which needed to be sanded down. The holes for the recoil pad aren’t even drilled on centerline! The receiver end needed a bit of cleaning up to look decent. Nothing wrong with fit, but the finish sucked.

Here is a shot of the rear of the stock, sanded flush so I have a surface to reference off of when I fill it with epoxy.

This is the cavity on the Speedfeed II series stock after cutting off an inch from the end. You can tell this series of synthetic stock has VERY thick walls and is nearly solid. The cavity is in fact, quite small while most synthetic stocks are mostly hollow with thin <1/16" walls which sounds tinny when you rap your knuckles on them. I’m going to increase heft by filling that void with epoxy.

I cut off a short length of cardboard tubing and use that as my epoxy form to prevent it from squishing into the cavity required to drop in the long stock/receiver bolt. The tubing was larger than the shouldered recess which the bolt rests so I put a plastic sleeve that dropped into the recess of the factory stock, sitting flush against the shoulder. This allowed me to keep the cardboard tube centered properly. I’m glad I did because a little epoxy squished past the cardboard tube at the bottom. The plastic prevented it from filling the cavity. I later reamed out the hole with a drill to clean it up.

I used Rectorseal EP-400 epoxy, a 4oz serving of two-part epoxy putty which must be kneaded together well to activate. It dries hard in 10-15 minutes.

I suggest kneading only small amounts at a time because it gets hard after about 5 minutes, unless you can work super fast. 4oz was just enough to finish my stock.

It took me about 15 minutes, working in three sessions to push in the epoxy, pound it a bit with the head of a nail to make sure any voids were filled

Five minutes after the stock was packed, the epoxy was hard enough to work with tools. The heat generated was warm, but not extreme. I ground off most of the excess on a bench grinder and sanded the epoxy flush with the stock. If I had a walnut stock, a synthetic stock, and this stock side-by-side and enough volunteers for a head-cracking cracking comparison, I think this stock might come out on top.

Now waiting for my Kickeez grind-to-fit recoil pad so I can grind it to fit and install!

2

Very cool! Why did you decide to fill the stock with epoxy? How does it affect the balance?

3

Looks like a very utilitarian mod.

I’ll certainly keep this in mind when settling on a stock for a sg.

Good work!

4

Thanks for sharing. That is some clean work right there and it gives me some ideas that I may try on a beater stock just for fun.

As an aside - do you have any practical experience with the KickEez pads on other guns? I’ve looked at them, but never could make myself go there.

5

The balance on a 18.5" 870 with a Surefire weaponlight fore end felt much less front-heavy with some extra weight at the rear. I’m waiting for the actual 870 this will go on before I take it out and zero it with slugs.

I decided to fill the buttstock with epoxy to add a little extra weight. I’m also adding a Grovtech flush cup for a QD swivel so the epoxy body will support some of the threads on that insert. I’m also entertaining the idea of adding a couple threaded inserts on the right side to hold a solid 4-shotshell carrier but I will probably sew a nylon mockup first to see how I like it. I’ve seen yeas and nays about such a setup.

I’ll post some recoil pad photos when I get home. I haven’t had the pleasure of doing side-by-side recoil comparisons on the various brands. I’ve got a Pachmayr Decelerator on my Sako TRG and picked up a dual-compound Kickeez which is supposed to be their flagship recoil-reducing setup. The Kickeez’s softer of the dual compound formulation was definitely gummy and hard to sand without tearing the material, even after I stuck it in the freezer. I’m not sure how durable it’ll be but hopeully that translates to tops recoil mitigation. The Kickeez definitely feels more absorby than the Deceleratoe. I don’t have a Limbsaver product around for comparison. I didn’t want to run the Mesa or Blackhawk springy sprongy systems or a pistol grip. My existing 870 is a pistol grip and I wanted to try the traditional grip on another rig.

6

Here is the recoil pad fitment. I’m sure a pro that does this has a much better, streamlined version but this is my first time and I think it turned out reasonably well.

Step one is to trace the outline. I’ve seen a lot of folks simply wrap the stock with tape and sand with the recoil pad installed on the buttstock. After a few beers, I don’t trust myself to do that so I screwed it on, used a scribe to trace the buttstock cross section onto the underside of the recoil pad, and used that as a guide, checking often.

Here is a shot of the recoil pad being roughed out. I highly suggest the trick of sticking it in a cold freezer to firm up the rubber before sanding. The Kickeez pad I selected has two compounds…an ultra squishy 1/4" layer next to the plastic and the rest being a standard compound. I found that the super squishy stuff tears very easily, being next-to-impossible to sand unless it’s firmed up by a good freezing. This means you’ll have to freeze it, do some sanding, then freeze it again to firm up the material. Repeat until you’re roughed in.

A photo of the progress. It’s slow, but methodical.

Here, I have to change the sanding angle so the bottom angled sweep of the buttstock is matched on the recoil pad. It takes a bit of free-sanding to blend it in. Mine isn’t perfect. It doesn’t really bother me that it’s not perfect. It might matter on some fancy trap gun but mine is going to get banged around.

Final sanding is done with 220 grit sandpaper wetted with WD-40 as lubrication. I still have to drop the pad in the freezer to firm it up but this allows me to get the recoil pad cross section flush with the buttstock.

Here is the finished product!

7

Great job on the stock & recoil pad! Those soft squishy recoil pads are a PITA to grind.

If you wanted to take it one step further, both Brownells and Midway sell an adjustable fixture to hold the recoil pad at the angle required instead of changing the angle of your sander table. It speeds up the process because it allows you to quickly set the fixture to the correct angle. Other than that, the process is the same as the one that you used.

Well done!

8

Thanks Dave! Those recoil pads are big squishy boogers if they aren’t chilled from the freezer. A fixture definitely would help blending in the angled bottom of the stock line to the sides of the recoil pad. The problem with just tilting the table is the angle didn’t blend properly and required some acrobatics to blend in.

It was a fun educational experience and it gave me the sense of workmanship that custom gunsmiths apply when doing hands-on work. I work in aerospace manufacturing so programming and setting machining centers is a bit of a clinical profession. It doesn’t have the same hands-on intimacy of running manual machines and crafting by hand. It’s always a treat when I find an excuse to hop on Bridgeports or Hardinges to whip up something. My coworker who worked at Mega voiced the same opinion. More fun to make dust on a grinder than make a 0.0001" offset on a machine.