DIY CF Stock Geometry Fix

Joined
Sep 8, 2014
Messages
1,742
Location
Front Range, Colorado
After spending weeks combing through and mulling over all of the stock options for my Tikka 6 UM build, I finally decided that it was time to do it right myself. Every stock on the market had at least one obnoxious design flaw, and nearly all had a lead time ranging from inconvenient to humorously absurd. Paying someone to get it wrong didn't seem like the thing to do, so I did this instead.
In terms of complexity I'd say this is just a little more difficult than bedding a stock. Anyone with the ability to bed a stock and watch YouTube could pull this off themselves. I believe that @ResearchinStuff did his own Tikka factory stock as well that turned out nicely.
The stock was originally a Manners EHT. I had previously shortened the LOP, added a 1" limbsaver, and added flush cups. There were 3 things to address originally, and I added a couple more later on.
  1. Vertical grip with correct distance to trigger
  2. Flatten the bottom of the butt of the stock
  3. Raise the top of the stock, and angle it upwards.
Additionally, since I was at it, I will also do the following:
  1. Carve a bunch of the bondo like substance out of the barrel channel, open up the barrel channel for a 3B contour. Add in two carbon fiber rods (arrow shafts) and fill with MarineTex mixed 50/50 with chopped carbon fiber.
  2. Add carbon fiber pillars, again from arrow shafts
  3. Fully bed with MarineTex.
  4. Permanently bond Lumley bottom metal
  5. Finish & paint
The process went as follows:
Mark out and cut stock for changes. I cut the grip, top, and bottom of the butt off
PXL_20230729_155028735.jpg
Carve/drill into the foam and filler so that the new foam can mechanically bond
PXL_20230729_155034754.jpgPXL_20230729_155037736.jpgPXL_20230729_155044462.jpg

Re-shape cut off pieces as needed. I reused the top and bottom of the stock but not the grip. They were positioned using wood screws to set the height. Something lighter could have been an option. Tape in place.
PXL_20230729_164035480.jpg
Fill with polyurethane foam. Pour foam would probably be better, this was canned Loctite Tite Foam and it was at least as good as whatever Manners filled it with. It does need oxygen to cure so the tape had to come off.
PXL_20230729_165341794.jpg
Carve foam down to shape. Leave room for Bondo layer and CF layers.
PXL_20230729_201209344.jpg

Use glass filled bondo to give additional structure and a smooth profile before adding CF. This step adds weight and may be omittable if the foam work is perfect. Mine wasn't so I added the Bondo.
PXL_20230729_211336396.jpg

Grind/file/sand bondo to smooth profile.
PXL_20230730_001925078.jpg

Do CF layup. I used a kit from Amazon with twill weave fabric. It does a pretty good job of following the contours of the stock. There are tutorials on Youtube on how to do it. I was being lazy and didn't use tape or a vacuum bag for consolidation, just a squeegee to remove excess resin. All three layers of fabric were done in one application. After that cured I added on more layer of resin to smooth things out. There were a couple stray fibers so I filed them off. The entire stock will be sanded and rattle canned in the next few weeks.PXL_20230802_233254398.jpg
 
OP
PathFinder
Joined
Sep 8, 2014
Messages
1,742
Location
Front Range, Colorado
Conclusions: The stock is profoundly more shootable than before. Head position is better, the grip is far more comfortable and conducive to a good trigger pull, and the flat bottom helps keep on target through/after the shot. It all just feels very quick and natural to shoot in all positions. The grip is a little wide, and it's no work of art overall. Definitely heavier than a properly consolidated layup. But I didn't pay $$ for someone else to get it wrong, and it's highly functional. The build of the Manners was rather unimpressive. It's really nothing that couldn't be done in a garage with a mold, some pre-preg, a very basic vacuum system and some time in the kitchen oven. In no way worth waiting a year and paying $1k for. It was a good starting template since I had it on hand though.
More to come when the barrel channel, bedding, and bottom metal are all finish installed.
 

TaperPin

WKR
Joined
Jul 12, 2023
Messages
1,979
That’s really nice - these projects really help to take the mystery out of stocks and there’s not an advantage to an adjustable stock if you customize what you have to fit.
 

Kurts86

WKR
Joined
Aug 15, 2020
Messages
351
This is a great project. I’ve done enough composite stock work to know you aren’t hurting these stocks with wet layup carbon, bondo and hardware store foam.

Most all the major rifle stock companies are using pretty crude composite manufacturing methods compared to aerospace or carbon fiber bike frames.

I like my manners stocks but the bottom of my LRH adjustable cheek piece is a crime against composite engineering. I’ve made cleaner composite kayak patches in my garage between back to back days of duck hunting.
 

Gobber

FNG
Joined
Aug 8, 2023
Messages
37
Great looking project! I like plinking with a Russian Biathlon style .22 and have made a few stocks for it myself. It really is amazing what you can do on a folding table in your garage after a bit of research. Vacuum bagging pump- no problem, use a salvaged refrigerator pump. Mine is still going strong after 9 years. A bit of West System resin, CF fabric & bagging supplies and your imagination is the only limitation.
A suggestion for filling in gaps and customizing grips is Epoxy Dough. Really light weight, rigid, No polyester stink, doesn’t melt foam, easy to shape once cured overnight and simple to add to if needed. I am doing a walnut carbon fiber stock right now where the grip area will be cut away and filled with epoxy dough. I can then shape and contour the fit over the next few weeks to fit my shooting needs. Once satisfied, I can lay on a few layers of carbon fiber using vacuum bagging and sand smooth. Fun stuff!
 
OP
PathFinder
Joined
Sep 8, 2014
Messages
1,742
Location
Front Range, Colorado
Great looking project! I like plinking with a Russian Biathlon style .22 and have made a few stocks for it myself. It really is amazing what you can do on a folding table in your garage after a bit of research. Vacuum bagging pump- no problem, use a salvaged refrigerator pump. Mine is still going strong after 9 years. A bit of West System resin, CF fabric & bagging supplies and your imagination is the only limitation.
A suggestion for filling in gaps and customizing grips is Epoxy Dough. Really light weight, rigid, No polyester stink, doesn’t melt foam, easy to shape once cured overnight and simple to add to if needed. I am doing a walnut carbon fiber stock right now where the grip area will be cut away and filled with epoxy dough. I can then shape and contour the fit over the next few weeks to fit my shooting needs. Once satisfied, I can lay on a few layers of carbon fiber using vacuum bagging and sand smooth. Fun stuff!
Appreciate the pointer, that dough looks like cool stuff! Wish I'd have known about it for this project.
Agreed, I'll never live with sub-par ergonomics on a stock again. My guess is we're going to see quite a few garage floor gunsmith stocks that are better than anything on the market from forum members.
 
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