cant keep the tang off the stock

[Whiterabbit]

Hi guys,

I have a hard kicking rifle. I bedded the recoil lug fully (no relief anywhere) and when I put it into the stock, there was a ton of clearance from the tang.

Fast forward to firing, and in a couple shots, the gap at the tang is gone. While action slid back.

Compressing wood?? what's going on here?




More importantly, how do I fix it? If I pull the action screws, I can slide the action back forward. Cool. So I mixed up new bedding, put some behind the lug, and reseated the action.

Shot it, slid right back again.

I need a permanent fix, and I really really do not want to pillar bed if I can avoid it. any solutions that do not go that far? I just need whatever the recoi lug is resting on not to compress.

[Whiterabbit]

pic is worth 1000 words. I should get a pic of the tang tonight, but this is from a few weeks ago:

http://castboolits.gunloads.com/attachment.php?attachmentid=98672&d=1394037171

Not the tang, but shows how much movement I got AFTER full-bedding. Again, with no relief around the recoil lug. Well, there sure is relief now! :(

[Ragnarok]

Maybe driving the cross-lug back into the stock too huh?

[Whiterabbit]

I do not believe the recoil lug is in direct contact with the cross-bolt.

[RickinTN]

A couple of questions for you. What kind of bedding compound are you using? and is the recoil lug in direct contact with the cross-bolt in the picture you provided? If so, re-bed in this position and relieve the wood around the tang a touch.
Good Luck,
Rick

[Whiterabbit]

I am using an epoxy-based bedding compound that uses milled glass fiber as the agent of strength (ie, this is GLASS bed, but not STEEL bed). I can almost guarantee the recoil lug is not in contact with the crossbolt. Might be now, but not when bedding.... (twice...)

[Mk42gunner]

Are you sure your bedding compound is fully curing? I never had any luck using acraglas without making a total mess of things. I switched to using accragel and I haven't had any problems, but the heaviest recoiling rifles I have used it on is a .338 Win mag and a .35 Whelen. I didn't use any crossbolts in the Whelen's stock, but no problems for several years.

For your rifle, I would cut or grind all the old bedding out and start over, with a tougher bedding compound -- either Brownell's Steelbed or maybe some Devcon plastic steel. If you bed it in two steps, recoil lug first with the hard tough stuff that can't be colored, you can finish with a color matched thin coat anywhere it might be visible.

Robert

[MtGun44]

There is no "tang" in that picture. The tang is at the rear of the action. The pic
is of the front receiver ring. Not sure what you are talking about.

Bill

[Whiterabbit]

Hey bill, I said upfront that the pic is "not the tang", but clearly showed how the action is sliding back in the bedding.

I'm sure the bedding is fully cured. The action has since been pulled and reinstalled a couple times (including a second bed to try to correct the first sliding).

Rick, I hear you loud and clear on your recommendation. What would you recommend if I pull the barreled action out and it's clearly NOT in contact with the crossbolt?

[leftiye]

Not sure at all what to tell you. Except that it is unheard of to have a recoil lug push bedding back. When you opened it up was the bedding all broken up? (that stuff doesn't move without breaking) Recoil is born right there, you can have the front and sides of the recoil lug not touching the bedding, but the back should be tight against the bedding. (I'm not insinuating anything about you not knowing that, just setting the foundations of a logical statement). Either it was not tight against the bedding or it shattered the bedding, or the high quality wood they use nowadays let go it would seem.

[RickinTN]

Rick, I hear you loud and clear on your recommendation. What would you recommend if I pull the barreled action out and it's clearly NOT in contact with the crossbolt?

It's been several years since I've done any bedding myself and I understand there are some stronger compounds available today than there were back then. I think my gunsmith (Bob Green) uses Marine-tex but I'm not sure. He has done all of my recent bedding, but that has been a while also. Steel bed is a product that comes to mind also. It appears the recoil is overcoming the bedding compound and trying to go to it's "happy spot", probably in contact with the crossbolt. I would examine the bedding to see if it is indeed touching the crossbolt. If it is, relieve the wood gently around the tang and re-bed in this position. If it is not yet in contact I would relieve the bedding and wood around the tang until it is and bed in that position. I don't see how pillar bedding would help your situation in that you want the load bearing on the recoil lug, and not on the action bolts in the pillars. Could it be that your bedding compound is aged and is not curing to it's original intended strength? Just a thought.
Good Luck, and let us know how it goes,
Rick

[nekshot]

Rick, I have bedded dozens of actions all in acragel and never had any movement, but I suspect what you are shooting might max eveything I did. What cardridge is this beast?

[Whiterabbit]

Thanks for the advice guys. Looks like my best option at this point is to relieve the tang a smidge and skim bed the recoil lug after inspection. I'll try to remember to take a pic for you guys to see, so you can offer me further suggestions or opinions if you like.

nek, the cartridge is 510 wells express. My dream big bore rifle. (that's a 223 on the table next to the wells loads)

http://castboolits.gunloads.com/attachment.php?attachmentid=97379&d=1393051258

this picture is not helpful at all, but I have it uploaded, so I'll post it. It is the bed job after the barreled action was pulled for the very first time. The angle is of course wrong to see what is going on in the area of our personal interest. Even if it were right, this was when the rifle was unfired anyways:

http://castboolits.gunloads.com/attachment.php?attachmentid=96704&d=1392361844

[country gent]

On heavu recoiling rifles bedding takes a real load of force. Every thing need to be filled and free of air pockets or voids. It has to be a solid mass to obtain strength. I would start with several things. first cut out all the old bedding and prepare to start over. On the stocks recoil lug face ( area that mates to recoil lug) cut this back roughly 1/8' to provide mass to strengthen the bedding when cured. 2 layers of masking tape on bottom, sides and front of recoil ( none bearing side) lug. This allows easier removal. 2 coats of release agent on action and recoil lug. Now mix bedding to instructions ( I perfer Bisonite steel bed) and liberally coat surfaces in stock and action, you want it to press out force any air pockets out. I use alighnment pins and a clampp to hold. Clean any extra of with a wood scraper ( can be made from a popcycle sticks) and clean soft rags. Let cure checking occassionally as some epoxies expand slightly when they cure. Let cure at least 24 hours 48 is better. Remove barreled action from stock and check if any air pockets show recoat with release and fill pockets with epoxy. On heavy recoiling rifles I like to allow them to cure for a week or so before shooting. Uoi need to maintain the 1/8" thickness for strength and stability.

[RickinTN]

Nice looking rifle there! Way too big a "boomer" for me, unless with a case-full of Trail Boss :-). Be sure and let us know how it turns out, and take care,
Rick

[oldred]

You say the compound is fully cured but are you just assuming it is because of the time since it was applied? How old is the material, or better yet how old is the activator part of the mix? I know some epoxy can be successfully used after having set around for years but the stuff does have a shelf life especially after opening, try testing the compound for hardness and see if it's a bit soft. If it is a cure issue it might seem hard until tested with a sharp point, if it's soft enough it will set back like you are describing and can easily do so without crumbling. That stuff should be very hard and almost feel like picking at steel when you test it, I have used various types of epoxies for years for many different purposes and I have seen these cure problems before and from what you are describing it sure sounds like a curing problem to me.

[Mk42gunner]

Yeah... The .510 Wells Express definitely generates more recoil than my puny .35 Whelen. Never thought I would say that four letter word about the Whelen, but so goes it.

You may have to add a recoil lug to the barrel like they did back in the 1940's and 50's.

I have seen a picture of an additional recoil fitting that is inletted into the forearm that the recoil lug bears against. I think it was in one of the Gunsmith's Kinks books from Brownell's, but I am not sure. Found it it is on page 31 of Gunsmith's Kinks III.

Good Luck,

Robert

[Whiterabbit]

Hi Old Red,

I cannot vouch for the age of the compound. It was about one day old as far as my shop was concerned, having purchased it that day or the day before. How long it sat on the shelf in the retail shop I cannot say.

How do you personally test for "full cure" in your shop? I could duplicate that test here and report back.

[oldred]

Fully cured epoxy would tend to chip rather than cut if you try slicing off a piece with a sharp knife or try scratching it with a scribe. It's hard to describe what to look for but fully cured epoxy will definitely feel a lot harder than semi-cured compound. Also you might try mixing a small amount and allow that to cure for as long as what you used on your rifle then try bending it to see if you get any flex, it shouldn't break like a piece of glass but it should take a lot of effort to bend it any at all and shouldn't bend but very little before breaking.

[pietro]

.

That beast of a cartridge would definitely call for a 2nd recoil lug, in the bbl channel, about 4"-5" ahead of the action's recoil lug.

I've done them by inletting a straight 1/2" wide x 1/8" thick piece of steel into the bottom of the bbl channel, with a 2nd piece of steel 3/8" thick x 1" wide x 1/2" deep welded to the straight strap at a 90-degree angle, down into the forend wood (also bedded).
The rear of the straight strap should have a hole for the tight pass-through of the front action screw/bottom metal screw thread boss, to act as an anchor for the action via the front screw/etc.


.

[Walter Laich]

I was thinking of all sorts of ideas until I got to the caliber. Got to say I'll sit by and watch this. Way out of my league

[Whiterabbit]

I really really want to avoid the second recoil lug unless I can get away with cutting a barrel band lug in half (thirds actually), and soft solder into place. Then I'm all for it. The rifle came with a bedding block, I can always put it back in, but I never installed a lug on this replacement barrel. There WAS a reason though I chose zero taper on the barrel after the chamber neck down to the muzzle, and that was to make it easy to solder on sight bases, the banded front sight, and even a lower lug if needed. I still really hope the strength can be improved sufficiently to not need it.

In the meantime, I pulled the action and relieved the tang a little. I figured I'd give this a try and see where it settles (I need recoil to settle the action in the final position). However, on inspection, I found the rear action screw is slightly, very slightly, bent. It precesses around the hole during disassembly. Looks like the rear action screw was acting as defacto second recoil lug.

In response to that, I am going to re-bed the recoil lug a third time and give it a week and a half to cure up on recommendation of the good folks here. Inspection revealed a good bed surface the first two times, so it's either soft inside the stock between the bedding and the crossbolt, or the wood is compressing. Either way, my hope is with a re-bed that I will take pressure off the rear action screw. If that continues to bend, I will have to replace it.

[Whiterabbit]

I was thinking of all sorts of ideas until I got to the caliber. Got to say I'll sit by and watch this. Way out of my league

You ever wanna build something heavier than a 458 win mag? you can learn from all my mistakes.

I will say, lining up the irons on this rifle is the most thrilling and exciting on any rifle I have ever shot. Scope rifle shooting holds nothing to the stimulus of shooing a proper safari rifle. (or even my improper one!)

[FrankG]

Devcon has a Steel Putty that sets up rock hard when cured. Don't use the the Liquid Steel as it is runny like the original Acraglas that was red and runny like syrup.

[Junior1942]

I do not believe the recoil lug is in direct contact with the cross-bolt.And there is your problem.


Either way, my hope is with a re-bed that I will take pressure off the rear action screw. If that continues to bend, I will have to replace it.

The replacement screw will also eventually bend. You need lug to crossbolt contact and probably two lugs to two crossbolts contact.

[oldred]

I just read this entire thread again and now my shoulder is aching!

[Whiterabbit]

Doesn't recoil more than a 3" slug in a very very lightweight 12 ga.

[swheeler]

I would look for steel bed

[Whiterabbit]

well, I have the rifle relieved and rebedded. Bedding looked great, so hopefully this time it "takes". No plans for the rifle for 2 weeks so I'm free to let it cure for a goodly long time. Good chance I'll pull the rifle for inspections before firing this time around too. I found .02" of clearance in the channel before rebidding tonight, the first time I bedded it I provided NO relief.

Pretty amazing.



And there is your problem.



The replacement screw will also eventually bend. You need lug to crossbolt contact and probably two lugs to two crossbolts contact.

Thank you. This will be the next course of action if this doesn't fix it. I'll move heaven and earth before adding the second lug if I can avoid it (I just don't think soft solder will hold), This thread has been so very excellent for providing a half dozen suggestions of things to try before going to lug #2.

[fouronesix]

Well, the recoil imparted by a 12 ga slug round is not the same or even close to that imparted by the 500 NE class of cartridge. The recoil energy of a heavy 12 ga load is about 50-55 ft lbs and the 500, depending on load and bullet, yields about 75-100 ft lbs. "FELT" recoil along with weight of gun and type of stock are different from what the recoil lugs and bedding may be exposed to. Of course the 500 NE class of cartridge can be loaded down to mild 45-70 levels.

Second the cross bolts in rifles are primarily to keep the stock from splitting and not intended to provide a recoil bunker or stop for the recoil lug. I don't know where that idea or advice comes from??

[Whiterabbit]

Well, the recoil imparted by a 12 ga slug round is not the same or even close to that imparted by the 500 NE class of cartridge. The recoil energy of a heavy 12 ga load is about 50-55 ft lbs and the 500, depending on load and bullet, yields about 75-100 ft lbs. "FELT" recoil along with weight of gun and type of stock are different from what the recoil lugs and bedding may be exposed to. Of course the 500 NE class of cartridge can be loaded down to mild 45-70 levels.

Second the cross bolts in rifles are primarily to keep the stock from splitting and not intended to provide a recoil bunker or stop for the recoil lug. I don't know where that idea or advice comes from??

Duly noted about the cross slot. Thanks for the input on this subject.

As for the quantitative recoil bit, of course. Noone here is confusing felt recoil for calculated recoil energy. Noone is confusing real data on the rigors a gun is subjected to and the construction components required to sustain function with perceived recoil when they respond in this thread "my shoulder hurts thinking about it". We all understand the distinction. We have to, to play in this sandbox.

[fouronesix]

As far as "no one" correlating the two??


Doesn't recoil more than a 3" slug in a very very lightweight 12 ga.

Anyway, I hope your re-bed solves the problem. The idea is for the bedding to absorb and distribute the recoil force over the largest possible area of the stock contacting the recoil lug (or lugs or other areas of recoil stress). A secondary lug forward on the barrel, by definition, simply enlarges this contact area by some amount. Although, I've found that at times the secondary lug up on the barrel can induce other issues like inconsistent accuracy and changing POIs with wood stocks.

By the way, when I bed actions I remove a fairly thin layer of wood then sparsely honeycomb the wood on the bedding-to-wood contact surfaces with a small ball head rotary bit. If the bedding compound you're using "collapses" again you might try standard JB Weld. It is strong and compression resistant.

[Junior1942]

......Second the cross bolts in rifles are primarily to keep the stock from splitting and not intended to provide a recoil bunker or stop for the recoil lug. I don't know where that idea or advice comes from??Are you sure about that?

[Whiterabbit]

I used the word "quantitative". Plenty of qualitative evidence correlating felt recoil to lots of factors like bullet speed, power of the gun, etc. It's all a massive logical fallacy and a downright lie, but we all know that correlation does not imply causation ;)

Anyways, I'm more interested in ontopic discussion, particularly the crossbolts at the moment.

[FrankG]

What bedding did you lay in ?

[Whiterabbit]

glass bedding. Specifically, epoxy base with milled glass fiber. Not steel bed, no metals present. The epoxy is considered the "hard" type. After mixing it has the consistency of loose peanut butter.

[fouronesix]

Are you sure about that?

For heavy recoiling rifles like the one in question, if the lug directly imparts recoil force on or is in direct contact with the cross bolt, then the likely outcome will be horizontal wood split-out (or some other damage) as the cross bolt is driven rearward under recoil. I'll stick with my assertion that the primarily purpose of the cross bolt is to help prevent the stock splitting in the vertical plane from whatever reason. So, IMO the cross bolt should not be in contact with the lug.... it's better position is about midway between the mag well and the lug recess and just forward of the action screw that may be positioned at the midway point. For light recoiling cartridges, the likelihood of recoil causing split-out or damage even if the lug is in contact with the cross bolt may be pretty low. BUT, 75-100+ ft lbs of recoil, as with the 510 Wells (aka 500 A Square), is not light recoil.

But these split-outs are even seen in rifles of very negligible recoil. Many stock split-outs in this area are simply the result of receiver pressure coupled with wood aging/drying exacerbated by the fact that a weakness was created in the stock in the first place with the large cutouts for the receiver, trigger and magazine.

Other split avoidance methods, especially for heavy recoiling rifles, could include but not be limited to: isolating the action screws from wood contact via pillar bedding, allowing wood clearance at the end of the tang, proper installation of a secondary recoil lug on the barrel, adding a second cross bolt in the web between the mag well and the trigger cutout, etc.

Here's a pic of the most common and recommended locations for cross bolts for most bolt actions.

[Junior1942]

Some expert opinions: http://benchrest.com/showthread.php?63035-installing-cross-bolt-in-new-stock

[Whiterabbit]

Well, CZ puts about a quarter inch of wood between the bolt and the recoil lug, so there's definitely no contact. Then my bedding on to of that. Very rough estimate. So this gun is not one that will have contact between the two.

If this stock cracks on me, it turns out a replacement will cost $200 from CZ directly. So, it might end up being a 'no harm, no foul' situation, depending on the outcome of shooting it the next two sessions.