Introduction: Building a Custom Rifle Stock
I recently picked up a Russian-made Izhmash "Biathlon Basic" in .22 WMR and although I was extremely impressed with the accuracy of the rifle "out of the box", the stock was another story. I was definitely underwhelmed. The original stock wasn't very comfortable for me, and was more appropriate for hunting than the target shooting that I typically do, so I decided to build a new one.
Goals for this design:
1) As light as possible
2) Somewhat adjustable
3) Symmetrical to accomodate weak-hand shooting
4) As simply constructed as possible
5) Keep costs down while keeping quality/function reasonaly high
There are a lot of target stock designs out there with more adjustments than I would know what to do with - but that "adjustability" adds complexity, cost, and weight to the stock. I also knew that once I had the stock set up for me, I probably wouldn't need to adjust it again, so I decided to sacrifice speed of adjustment for simplicity. I also chose a rather... uh ... "unique" way of building this stock - namely, I took the original bedded stock, cut away all the parts I didn't want, and built the new stock around the skeleton of the old one. Why? Because "inletting" (machining the stock so that it holds the action of the rifle) is one of the more complex and time-consuming parts of building a stock and I knew I'd probably just throw the original stock in a closet and forget it forever (and be annoyed every time I had to move it out of the way) ........ aaaand I was feeling lazy.... but mostly because I was feeling lazy. I don't think I'd use this technique on a higher-powered center-fire rifle, but in this case I wasn't worried about the small compromise in structural integrity between this method and machining the stock from a solid piece.
This is the first "from scratch" rifle stock I've built (besides the inletting) so I planned on painting it from the outset - thus making the building process a *little* less stressful since mistakes can be corrected (filled) without it being as obvious as it would be on a natural wood stock.
- Rifle stock blank (laminated blank from Boyd's - boydsgunstocks.com) - $40
- Fillers (Epoxy-Sculpt and Bondo) - $10 if you don't already have some
- Primer (Epoxy-based catalyzed primer in a can) - about $22
- Paint (Duracoat paint and overcoat) - about $43
- T-Trak aluminum rail (in leiu of a "genuine" Anchutz Rail) - $20
- Threaded insert (1/4-28 threads) - $.50
- Knock-Down pins (used as alignment pins on the adjustable comb) - $3
- QD Sling Mounts (mfg by Uncle Mike's - 2 sets) - $32
- Small piece of Brass for the butt-plate slider
- Allen-head Cap Screws - 1/4-28 x 1" and 1/4-28 x 2 1/4" - $2
- Various #8 screws, epoxy, urethane glue, sandpaper, etc.
- Pachmayer recoil pad - grind to fit - $20
- Total: ~ $195
Total time: ~50 hours over 5 weeks.
Step 1: Design
I spent a lot of time looking at other stocks, and although I really like the look and feel of thumb-hole stocks, the action of this particular rifle (a "toggle-bolt") is better suited to an "open saddle" type design - so after a lot of sketching and thinking, I decided to model the stock on the beautiful Sako TRG 22 (which was also convenient since a friend of mine owns one and was kind enough to lend it to me for a while to use as reference. Thanks, Mike! :)
The design was mocked up in Photoshop based on some pictures I took. In the image with the 3 rifles, the top is the Sako, the bottom is the original stock, and the middle image is the offspring of their union ;) The Sako's action is shorter top-to-bottom and the magazine well sits in a different location, so while I could take styling cues from the Sako, I couldn't *copy* it, per se. There were also a few details I wasn't in love with on the Sako - namely how "fat" it feels - so I knew I was going to change that as well on my design.
Once I was happy with the look and layout, I used the "Find Edges" filter in Photoshop to make it into a line drawing, then printed it out at 100% scale and made a template to work from.
Step 2: Prepare the Original Stock
Prepare the Original Stock:
Note: Anyone doing their own inletting can skip this step..... ;)
As I mentioned before, "inletting" a rifle stock is the process of cutting out the appropriate spaces, holes, and grooves into which the rifle barrel, receiver, and trigger group will drop into and be securely supported. This can be a complex shape, or, a relatively simple one depending on the rifle mechanicals in question - but it's precision work and can be tedious when you are working with a relatively unknown rifle (like this one), and no inletting diagrams are available.
I built a "sled" to help keep the stock oriented and well-supported as I shaved off the sides of the original stock. The sled was indexed off of the magazine well and the barrel channel. Once the sides were trimmed away, I cut away the parts of the fore-end and grip that I didn't need, leaving me with a rather stumpy stock - and firmly pushing me past "The Point of No Return"..... now, I was committed .....
Step 3: Prepare the Laminated Blank
Prepare the Laminated Blank:
I ordered a standard brown-laminate stock from Boyd's Gun Stocks ( http://www.boydsgunstocks.com ) and with a little maneuvering got my template to fit perfectly. I planned to to split the laminate stock open and "sandwich" the old stock in between laminate outer "skins" about 3/8" thick. The thickness of the inner "core" of the laminate was determined by the thickness of the shaved down stock. I measured this, and sawed the outer skins off using a bandsaw. I tried to pay attention to where the laminations and glue lines were, and placed my cuts so that I could hide the seam in the laminations when things were reassembled. The middle piece was cut a bit thicker than I needed and planed down to it's final dimension using a thickness planer. The outer panels were also cleaned up with the planer - again paying attention to laminations again so that the final assembly would be seamless.
After clean up and before cutting away the profile, holes were drilled to reproduce the arcs of the trigger guard, magazine well, and front stock bolt.
The middle "core" of the stock was cut away to accommodate the old stock, a floating mortise and tenon was fabricated to reinforce the junction where the rear of the old stock met the new laminate section, and the front and rear of the laminate sections were bonded to the old stock using polyurethane glue (Gorilla Glue - my preferred brand) and a sturdy straight-edge to keep things aligned during glue-up.
Step 4: Glue Up
Make Me a Sammich! (OK - You're a sammich....):
Once the "core" part was cured, any voids were filled with a putty made by mixing 5-minute epoxy-and sawdust. The sides were cleaned up on a belt sander once the epoxy had cured. The side panels were then glued on with polyurethane glue - but - I was especially careful to stop the glue line just past the grip area since I knew I'd be wanting a narrower buttstock and comb. By not gluing this section of the panels to the core, I was able to later just grind through the thickness of the outer panels at those spots and pop off those areas of the sides of the buttstock area. It sure beat having to grind off about 3/4" of material later on. Once the glue was cured, the squeeze-out was removed (with a sharp chisel), any voids were filled, and the rough shape was cleaned up with a belt sander (just to have a clean edge to work with).
Step 5: Cutting the Profile
Next step was to trace the profile onto the blank in preparation for cutting out the profile. In the pictures, you'll notice I left a little "wiggle room" around the magazine well area - I wanted to mark the final shape with the magazine and action installed so that the protective "wing" shapes were properly placed.
The piece for the adjustable comb was cut with a lot of "slack" and shaped later - this made cutting the buttstock a lot less stressful (as opposed to trying to cut it out and make perfect cuts on a bandsaw)
When cutting concave radii, I found it was easier to cut shy of the line and use files to clean up. Most flattening of areas was done with a coarse mill-cut file, and in tighter areas, rat-tail files were used. Broad convex areas were smoothed with a flat or half-round file. Concave areas were smoothed with a half-round or round file (rat-tail file).
Once the profile was roughed in, I glued two strips of birch on the fore-end to provide material for the "finger swells" on either side. One the glue was cured, I trimmed the gross excess with a handsaw and then used a belt sander to sand the bottom edges flush to the existing fore-end.
Step 6: Scuplting and Shaping
Tip: I break up projects into "mini-tasks" and make task lists - this helps me be efficient and focused and keeps me from feeling overwhelmed or getting burned out. This also allows me to put in just 15 or 20 minutes (enough to complete a task) and still feel like I'm making progress.
You've GOT to have a flexible and secure way to hold on to your workpiece - without it, you'll triple your effort just wrestling with the piece - and quite possibly damage it. I use a Zyliss vice that I bought years ago at a woodworking show (also sold as a Z-Vice and Grip-Master) but a pattern maker's vice (Tucker or Emmert) or gun stock vice would be awesome. Hey, I can dream, can't I?
A strong light source positioned at the height of your workpiece (natural or electric) is extremely valuable for checking contours and finding flaws.
Microplane rasps are similar to rasps in that they cut very quickly, but unlike a rasp they leave a fairly smooth surface. The downside is that they get dull more quickly than I'd like, are easy to bend, and are a bit expensive - but they make up for those shortcomings with speed and ease of use - and I still buy them.
Surform tools are a little too hard to control for this kind of work (IMO) so I don't use them - though they might be useful for heavy rough-in work if you don't have a Holey Galahad ;)
I use a Holey Galahad on a 4" angle grinder for most of the rough-in work I do - it's an *amazingly* useful and rugged tool. It's very controllable, leaves a decent surface, and removes material extremely quickly (and that's the *fine* version) - well worth the money (about $70).
If you don't have a file card or a wire brush, GET ONE and use it often. Using files and rasps without having a file card to clean the teeth is very frustrating and counter-productive. A clean file stays sharper longer - and you should always clean wood dust from files as it can hold moisture which leads to rust thereby shortening tool life.
If you have dull files/rasps - buy new ones - the extra expense will pay off in accuracy and saved time and frustration.... and you'll have them for the next project ;) Dull files can be useful when doing final smoothing of an area, but they cut too slowly for shaping work.
Let the tool do the work. This applies to pretty much every tool out there - even power tools. Pushing harder than necessary rarely makes a tool work better and can actually dull them more quickly. Even sandpaper works better and lasts longer with light to moderate pressure.
Patience is a virtue - especially when carving/sculpting. If you find yourself wanting to rush, find something else to do for a while until the feeling goes away. Rushing leads to mistakes that will cost MORE time to fix and/or substandard results..... I know this because I'm a chronic "rusher" - lol.
Some general concepts here:
- Refine shapes progressively throughout the entire stock - don't let one part get close to finished while other parts are rough - keep moving around and keep the overall shape in mind.
- Remember that all curves can be broken down into a series of straight lines - rounded edges into a series of "flats".
- Leave sharp contour edges as long as feasible - they're your landmarks when doing general shaping. Wait until shapes are just where you want them before smoothing things out.
- Half of your shape checking should be done with your eyes closed - by feel - and the other half visually. It's surprising how many shape flaws *look* perfectly fine, but feel "wrong" and vice versa. Find a spot that feels wrong, put your finger on it and open your eyes - you'll be surprised how often it's NOT where your eyes would tell you it would be.
- Pay special attention to where your hands go - does it feel smooth and flowing? Are there uncomfortable bumps or swells in the wrong place? Does an area need to be filled out more? Does your hand grip the stock naturally with no pressure points?
- Use power tools where they make sense, but don't go out of your way to *make* them work. Often times, a few minutes with a hand tool will do the work just as well - and there's something very "Zen" about hand tools - it's like meditating ;)
- Check from side to side often. Draw projection lines across to make sure you're keeping symmetry (if you're going for symmetry, that is).
Step 7: More Sculpting and Shaping
If a picture is worth 1000 words, this Instructable has about 175K words - so I'll let them do the talking.... ;)
Step 8: Adjustable Buttplate
The buttplate of this stock adjusts up and down about 2-1/2". The buttplate rides in a cove cut into the back of the buttstock. This cove acts like an alignment track and keeps the sliding portion from rotating around the length-wise axis of the rifle (when the bolt is snugged down). This is really nice because just one bolt needs to be tightened or loosened to move the buttplate, and once it's snugged down, it's very secure.
The buttplate is made from hard-maple - simply because I wanted a finer-grained material for this part of the stock.
Step 9: Fore-end Rail
Some target rifles have an "Anschutz rail" on the front - it's a versatile way to mount accessories like bipod mounts or fore-grips. The problem with "genuine" Anschutz rail hardware is that they are pretty expensive - so - I substituted a section of T-Track which for my purposes will work just fine.
Step 10: Adjustable Comb (no, Not That Kind of Comb)
The steel pins you see are just knock-down hardware alignment pins you can pick up at just about any big-box hardware store or on the net. They were screwed into the holes left by the screws, and the heads were ground off.
This design requires spacers to change the height (as opposed to locking columns) - but I can live with that because - like I mentioned before - once I have the stock adjusted where I want it, I probably won't touch it again. I can live with a little inconvenience to save weight and complexity that I don't need.
Step 11: Paint Prep
A good paint job is determined more by the prep work than any other aspect - so - take your time.
One of the interesting things about working with laminates is that the laminations provide nice visual feedback regarding the contours you're creating. As you remove material, the laminations take on a "topographical map" look - and it's easy to see where you're getting off course because the lines will no longer look "fair" (a term used to describe smooth flowing curves). The downside of the laminations is that they will do a pretty good job of hiding the *smaller* flaws that will stand out like a sore thumb once painted - so - a few techniques are used to ferret out those annoying little dips, scratches, bumps, and lines. Too bad it doesn't work on skin - lol.
Step 12: Color Me ... Green
I used an epoxy-based primer that comes in a rattle can. You can buy this kind of primer in epoxy or urethane-based formulations at most places where professional automotive paint supplies are sold. These primers contain the catalyst/hardener in a capsule inside the can - you place the provided plunger head over a valve head on the bottom and give it a good "whack" - this breaks the capsule internally and you shake the can to mix the hardener into the paint. This primer is hard when cured, builds extremely fast, and dry-sands very well - which is a huge bonus when working on a wooden piece. It's always a good idea to use a primer that's as close to your final color as possible. Unfortunately, they only had a light beige when I bought the primer - not a dark grey, black, or green like I wanted - oh well :)
The process of finishing should be familiar to anyone who's done automotive painting - it's basically 1) Prime, 2) Fill, and 3) Sand - repeat as necessary to achieve a smooth surface while trying to keep the thickness of buildup to a minimum. It's important to realize that paint has thickness - and if you have parts that fit closely, you can ruin that fit pretty quickly with too much primer/paint.
I used both "spot putty" (basically really thick primer) and polyester body filler as filler materials and did most of my sanding with 220 grit stearated sandpaper. Stearated sandpaper has a coating which helps prevent clogging.
The color coat is Duracoat applied with an airbrush. Duracoat is a brand of catalyzed urethane specifically formulated for firearms by Lauer Custom Weaponry (http://www.lauerweaponry.com). It's a bit finicky to apply, and it's not cheap, but once fully cured it's extremely durable. I applied three coats over three days with some light wet-sanding in between coats - using black for the adjustable butt plate and "AUG Green" for the body of the stock.
Step 13: Final Touches - Hardware and Assembly
Now it's time to make the comb spacers and mount the rest of the hardware. This is actually the fun part as things are starting to come together and it's beginning to look pretty nice. Still, you have to be patient as these are the details that make or break a project...
The fore-end rail and butt-plate track are actually T-Trak - a type of aluminum track that's generally used to make shop jigs - a 48" track cost about $20. The great thing about using this is that if I should somehow damage the one that's installed, I can just cut another piece and make a new "Anschutz rail" for a few dollars and under an hour's time. A small 7-slot polymer picatinny rail made by Magpul slides into the track and can be adjusted and locked down to accommodate installing other accessories (like a bipod) - or removed completely to reduce weight and clutter.
The comb (cheek piece) can be raised about 3/4" at 1/8" increments using spacers I made from aluminum stock I had lying around. I also made a 1/2" wooden spacer that's a lot lighter just to have around. The aluminum spacer stock was rough cut to size on the table saw and then double-face taped together into a "block" that was shaped using the belt sander and drilled on the drill press. The final finish on the aluminum was achieved by wet-sanding with 320, 400, and 600 grit wet/dry paper. The pieces were then peeled apart, cleaned up and re-stacked on the alignment pins on the adjustable comb.
1/2" holes were drilled in the fore-end and buttstock using a Forstner bit, and Uncle Mike's QD (Quick Detach) sling mounts were installed with epoxy. QD mounts are great as they don't leave behind anything to get snagged on when you remove your sling.
Step 14: Complete!
That's about it! I'll probably update with a range report when I get the chance. I hope you find something useful in this instructable and feel encouraged to do your own. Thanks for taking the time to slog through it - lol :)
EDIT: I got a chance to range-test the new stock this past weekend - it works very well. Results speak for themselves ;)
On a side note, this instructable is entered into the ShopBot challenge - so vote for me if you feel so inclined :) If I were to win a ShopBot, I can see myself using it to produce a lot of the furniture designs I've got rattling around in my head, sculpting some of my CG character designs, as well as custom lighting, computer cases, dog kennels.... man, the list just goes on and on. I'd probably have to be reminded to eat and breathe every now and then - lol.