Home Forums Hunting & Shooting Gunsmithing Crack in stock Q

My custom Rem 722's stock has a crack in the internal section between the middle action screw and the trigger group. Do I care?
FWIW, I see no indication that the screw contacts the wood. The crack is not quite complete to the bottom of the area, although I expect that if I pulled the sides of the stock apart at the mag box I could force it.

macrabbit
I would be very afraid of the bedding. Something is probably moving during recoil. I do not use the middle action screw and simply anchor the forward end of the trigger guard with a screw in the cracked web you are talking about.

If I were you I would simply rebed the whole action, cut out on either side of the crack and make sure the bedding fills that area. Replacing the middle screw would be my first concern however...

Once a crack show itself it is obvious the stock is being subjected to stress. It could be simple wood shrinkage or warping after the stock was built. Or worse, a case of improper bedding. Neither one will fix itself... But a simple rebed will fix both.
art

You might be able to repair it with Super T cyanoacrylic from Brownell's (made by CA Glues in Simi City, Calif.) Super T is the thinnest of three such glues they make- it's the consistency of water and will wick into a hairline crack. If you can open it just a tiny bit it will help, though. Run a little lacquer thinner in first to remove any oil in the wood.

I used this on a hairline crack in the wrist of my Marlin 1895 and it hasn't budged.

<img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> Stuart

It worked well for me also. Thanks...Bill.

Cyanoacrylate has almost no shock strength. In gradual pulls it is great, but any vibration destroys it. If it appears to be working in a similar situation... ie. short cross-grain glue-up... it is because it was not really holding anything.

I use a lot of CA and it is great stuff for the right uses. The water-thin stuff wicked into punky wood will make it hard! The better stuff to use in a shock situation, if you have to try CA, is the Super thick formula. It has considerably more shock strength, though nothing near epoxy...
art

Sitka, you used words that surprised me with their severity, so here are a couple of pics. Notice that the wood is well away from the middle screw. I don't see that any forces act directly on the cracked section.
The stock was made 30 years ago, is a wood to metal fit without any bedding compound (and will stay that way unless absolutely necessary). The 'smith, a family friend, passed years ago.

I'm surprised as well, but you obviously have quite a bit of experience with the stuff and know whereof you speak. Upon reflection, I can see that cyanoacrylates might be brittle, whereas epoxies are more flexible (relatively speaking.) I haven't tried abusing my Marlin 1895 so I don't know how it would take a sharp blow across the wrist, for instance. I do recall trying to pry the crack apart a little after the gue set up and it remained firm. so I have to conclude that it did the job. (The wood in the wrist was hard and dry.)

However, I know that AcraGlas is typically used for such repairs. The reason I didn't use it was that the crack was pretty thin and I was unsure if I could get it right down to the bottom.

FWIW, I did some searches on "thinning epoxies" and found a good article, originally by the people who make the West System epoxy products:

http://www.seqair.com/skunkworks/Glues/WestSystem/Thinning/Thinning.html

Their conclusion is that it is preferable to warm epoxy to thin it rather than using a solvent. Lacquer thinner (> 5%) seemed to work best in their tests but with adverse consequences to the strength.

<img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> Stuart

Macrabbit,
Easiest thing here is just don't worry about it. Many stocks crack thru this little block, including our McMillan Fiberglass stocks. It happens because when you shoot the rifle the recoil impulse hits the stock at the recoil lug, and everything from the lug back flexes a little. The side walls of the stock along the magazine box actually flex out a little each shot and this pulls horizontally on this little piece of material, and it cracks. If it really bothers you, just cut the block out completely, it dosn't have to be there. It's really just there to support the front of an ADL trigger guard. Many inletting programs for other actions do not have any material at all between the trigger slot and the magazine cut out and they all work just fine. Dick D.

Thanks.
That's the question, 'should I worry'.

I'm hoping Sitka pops back in and says that my pics explain better than my initial words, and that he'd not be concerned about the situation.

Yes, indeed , they can crack in the web behind the magazine opening. Lots of them do. But the next area to begin cracking if you don't secure the back of magazine web is the area behind the trigger mortise and from there to the wood behind the tang screw. The same forces continue with every shot fired and if they cause the web to crack they don't always stop there (although some do). If you look at some heavy magnum rifles you commonly see two cross bolts installed. One supports the recoil lug and the other supports the web behind the magazine. Some really heavy kickers have a third crossbolt behind the rear guard screw. Their collective purpose at each location is to put the wood under compression and reduce the bowing/flex that can occur down the sides of the stock. The purpose of the large spanner nuts on these cross bolts is to achieve compression. A simple steel pin simply attached (epoxy usually)in constant diameter holes through the stock does not provid any compression and cracks can still occur.

On moderate recoiling rifles you can live with the split web for quite a while, perhaps indefinitely. On very heavy recoil rifles it is the sign of further things to happen that you won't like.

Either way it affects the rigidity of the union between rifle and stock.

Your words aren't nearly as welcome as some from Ed McMahon and the Clearinghouse!

It's a lowly .257.


Sitka, why do you write of replacing the screw?

mcrabbit: I think Sitka was referring to using a wood screw when using the ADL trigger guards rather than a dropping floor plate (BDL) style.

If it were my rifle I would at least repair the cracked area at a minimum. My glue of choice for these is still a good epoxy. If you carefully spread the crack you can usually get 100% glue coverage by using compressed air to get the glue distributed in the crack. No compressor? Buy a can of compressed air from a store that sells computers. It's used for blowing dust bunnies out of the tower.
You should also see if the recoil lug is making solid contact with the mortise and that the rifle isn't getting a running start at banging the stock. If there is any free space you should either glass bed the action and recoil lug as Sitka suggests or install some shim stock behind the recoil lug to push the action forward a bit in the stock.
Also check all your guard screw holes for sign of blackening/buffeting from the screws coming in contact with the wood as an indication of improper fit.
Do not over tighten the middle screw as that can cause a stress situation on the action which tends to force the stock sides apart.

As for it only being a 257, people use 257's in different ways. Some prairie dog hunters may shoot many times a day and deer hunters a lot less in a year than the varminter does daily. The recoil effects on the wood are cumulative.

I drilled a 1/8" hole in the center of the crack on one rifle stock I had and used the 2-part epoxy made like a syringe, blocked the bottom of the hole I drilled, and then forced the epoxy until the crack was saturated, along with the hole. Worked for me. Thanks...Bill.

Stocker, you a smart man who understands how things work. Wish everyone did. Dick D.

The front screw hole has a touch of shininess on its front. That's the wrong side for what you're thinking, right?

How does one test seating of the lug? The face behind is quite smooth and black- I'd think that is a good indication.

Is this what you mean, model70man, a plug of epoxy in this position?
How does that method sit with the others helping me?

macrabbit: I would do a straight epoxy glue job initially so you can clamp the area and get it solidly back together. I would probably follow that up by cutting a trough from side to side ,through and well beyond the pink circle. You can actually extend it into the side walls of the stock a bit . The trough neds to be deep enough and wide enough to accept a section of about 1/8 Redi- rod and you can flare the ends of the trough so a mechanical lock also exists. Lay the Redi rod in a bed of glass bedding compound and then fill to level with glass aall the way across.

A mark on the front side of the screw hole won't matter except possibly for accuracy provided the hole is drilled square and the tightening of the screw is not walking the barreled action back and forth.

Try assembling the rifle while the whole thing is standing on the butt. When you slip the action into the stock you should try to feel for contact of the recoil lug against the stock. Place masking tape strips on the action and stock (separate pieces) with perfectly alligned fine index lines. As you tighten the screw do you see any deviation in their allignment? If there is you may find that when your screw is tight you have walked the action forward off the mortise a bit. Also check the screw for straightness as that can cause the same effect. If you don't want to do a full glass bedding job that reinforce should give you a lot of strength in that area.

It's going to take me awhile to digest that post (I'm neither a woodworker nor a 'smith), so I'll be back later.

I appreciate all of this help, guys.

macrabbit
I agree completely with what DickD said. The crack means little in most situations. But it is exactly why I prefer the ADL style trigger guard. Having a continuous chunk of wood makes the action area of the stock stiffer and stronger.

I mostly agree with Stocker on his fix suggestions with a couple minor disagreements. I have never found metal rods to be worthwhile for fixes. Reinforced epoxy will fill a void and be plenty stout. His point about bending the ends to make a mechanical bond is exactly why I do not like them. They will "work" under temperature changes and break free of the epoxy. The bent ends will keep that from showing, but will not make it stronger. I have seen far too many of them fail to accept their use.

When I said the CA worked only because it was not needed I meant the stresses were not stout enough there to worry about. I would be inclined to skim a bit of wood off the top of that webbing and apply epoxy down in the crack. (work it open and closed and the epoxy will migrate down in there a bit.) Then I would lay a piece of fiberglass cloth on top and soak it with epoxy.

However there is one immediate concern and that is the cause of the crack. It may have been there almost from day one because the wood may have dried enough to allow the wood to shrink and crack. The fact the crack is standing open leads me to believe there is a good chance that is the fact. If it is, you will need to leave it open and reinforce as I suggested in this post.
art

"leave it open" why? Because the wood's out-of-the-action state is open and natural, so don't clamp it closed and add that unnatural strain to the epoxied bond?

What sort of epoxy, or would any alert person be able to figure out at the store which types are unsuitable?

"reinforced epoxy"? Is that satisfied by the fiberglass cloth or do mean something else?


(I don't know from ADL or BDL, so you'all are losing me on stock styles. And remember, this is the pre-700 model 722.)