Gunsmithing The Importance of bedding

[LRI]

Before us is a target rifle I built almost two years ago. It's a Barnard action based unit with a rather nice piece of "railroad tie" for a stock. When completed this rifle generated quite a bit of interest amongst various folks. The owner was gracious enough to give me a long leash while building it and I took advantage of the freedom. Performance was really good as it delivered many cleans and 199's with good X counts.

Then things went to crap. The owner is a very visually detailed driven person. He's about as particular as they come. That being said he decided to have the receiver blued again as the finish wasn't to his standards. The shop where he sent it in did a very nice job. It looks great! However they were a bit aggressive when polishing and as a result the fit in the stock isn't anywhere near what it used to be.

The data book tells the tail. Shot plots at 600 and 1000 resemble a flying saucer. Still holds great elevation (around 1/3rd minute-seriously!) but left to right is fanned out in this odd saucer shaped profile stretching all the way to the loose side of the 9 ring.

Bummer.

Close inspection of the bedding shows the gaps. This receiver used to "suck" into the stock during assembly. Now it's like a hot dog in a hallway if you know what I mean.

So, the challenge before us today kiddies is to bed this stock without chewing up the exceptional finish on the outside. I want to avoid removing the pillars since its such and invasive process here and keeping the bottom side of the stock clean is a bitch when doing these over. Especially on a finished gun.

Boldly going where I've not gone before I decided to modify the original programming a bit. I generated "check" surfaces around the pillars so that the machine will only inlet the bedding. Came out perty decent me thinks.

With a .05" stepover the residual scallops left in the original bedding should make for a nice "grabber" when we pile in the fresh goop during the "remix."

The point here is the polisher prolly only removed at most .002" off the receiver. He'd of had to smoke a great deal of meth to be obsessive enough to go any further. .002" is less than most human hairs. (even red ones

) yet it created a real mess of this rifle.

Lessons?

When its not broke, don't attempt to fix.


More to come as we progress along with this today.

Thanks fer lookin!

C.

 

[Maddyn]

Re: The Importance of bedding

That is one nice looking piece of wood, was that seriously out of a RR tie? amazing what you find sometimes in "junk" pieces of wood... I cry every time I think about all the burl maple we used to burn for firewood

 

[Shortdraw]

Re: The Importance of bedding

Crazy to think that .002 would do that, but when you're talking serious precision... He brought it to the right shop.

 

[Keith Johns]

Re: The Importance of bedding

Problems come up like this when people send out rifles for Cerakote, that have already been bedded.
Cerakote goes on about .001" thick. This adds .002" to the diameter of an action. I have seen problems fitting a coated rifle back into a bedded stock.

Please keep this in mind guys if considering Cerakote for a bedded rifle.

 

[LRI]

Re: The Importance of bedding

Funny.

I always coat barreled actions after bedding them and they assemble/shoot just fine.

Here's the receiver all masked up.

One more of the stock before I pulled it. Chunking out where the lug goes.

 

[LRI]

Re: The Importance of bedding

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Maddyn</div><div class="ubbcode-body">That is one nice looking piece of wood, was that seriously out of a RR tie? amazing what you find sometimes in "junk" pieces of wood... I cry every time I think about all the burl maple we used to burn for firewood </div></div>

I was being cynical when I called it a RR tie. Its actually exhibition grade Turkish walnut. Retail a piece of wood like this turned into a stock like this with all the hardware would go for around $4,000.00.

 

[Keith Johns]

Re: The Importance of bedding

How are you fitting a barreled action back in after adding at least .002" to it?
Yet this entire post is about how removing .002"(maybe less) from an action ruins its previously done bedding job.


To customers, regarding the coating of pre-bedded rifles I say, coat at your own risk.

I prefer bedding to be done last, so the fit is perfect. Feels air tight when pulling it out. They feel too tight to me if you bed, then coat. Which makes perfect sense. Especially if you bed the front of the lug too like I do.
The whole point is that is stress free and a perfect fit.
I dont understand coating after you bed. Why not bed last?

 

[300sniper]

Re: The Importance of bedding

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Funny.

I always coat barreled actions after bedding them and they assemble/shoot just fine. </div></div>

as do i.

 

[Keith Johns]

Re: The Importance of bedding

And it doesnt feel tight to you?
Do you only bed the rear of the lug?

I've Cerakoted all of mine before bedding. Bedded once it was cured. Its just as easy to bed then and not scratch anything. And it feels so perfect when sucking it in and out that I swear it feels air tight. Seems like you feel suction even though thats not possible I dont think.
Cerakoted a barreled action for a man that had already bedded it. Had to open part of it up and re-bed.

Lugs dont fit by along shot when you bed front and back.


Maybe you should try the spray on release agent

Just kidding on the release agent.

To each their own. We coat before bedding. And I thought it was common practice among builders to do the same.

Learn different stuff every day.

 

[GSully-2]

Re: The Importance of bedding

Extremely intelligent and superb procedure for repairing this great piece of gun stock!

 

[LRI]

Re: The Importance of bedding

Keith I'll put my bedding/barrel/action work against any one in this industry. I'll lock horns and drag out a fight till the bitter end.

I can't count how many rifles I've done exactly the same way for the last 8+ years and I've yet to have one screw up yet. They shoot, customers marvel at the finish, and if you pull the actions screws out they receiver will <span style="font-weight: bold">literally fall out of the stock.</span>

Tension free means tension free. It does not mean it should produce varicose veins in your forehead as you try to pull it without rocking the lug.

To this commandment that one must never pull a barreled action from a stock I call BULLSHIT! My guns assemble/disassemble infinitely without issue. That means no mysterious headaches where it won't line up with guard screw holes, ghetto half ass washers under the floor plate rolling all over the floor upon dissassembly, magazine boxes failing to line up, etc. Most importantly there's NO ZERO SHIFTS.

"NO" means ZERO's remain consistent. Case in point. Palma guns are just too long to fit in all but a purpose built custom case. Sights are taken off during transport, barreled actions are pulled from stocks, yet at a match the first cold bore shot down range will almost always hit the target if its a high master ranked shooter.


You should never be fearful of a recoil lug shaving off material as you install it. Do that a few times and forget to clean it and you can quickly end up with a pressure point right under the lug due to material being squished during assembly.

Regarding coatings:

Ceracoating runs anywhere from .0006" to .001" So we have an action that increases in size anywhere from .0016" to .002" after being coated.

All resins shrink during curing. How much they shrink depends on the quality of the material and the volume of material present when cast. I set a gap of exactly .05" at all points between stock/receiver. That means <span style="font-style: italic">everywhere</span>

1% of .05" is .0005" now multiply this times 2x because its on both sides of the receiver.

.001"

This tells me I have .001" interference on a non coated action and either .0026 fit or +.004" interference on a coated one.

While the math suggests this I'm not really buying it because I know what a .002/.004 interference fit feels like and I can assure anyone the stock/receiver fit doesn't have this.

Now I'm sure your asking, "well why do mine go in tight then?"

I'm betting dollars to doughnuts your buying preinletted stocks and skin bedding them. Your film thickness is narrower and it's likely very inconsistent. A narrower film thickness means less distortion/movement in the bedding as it cures. It also means a potential for chips, flakes, and poor resistance to impact, torsion, and compression over the long haul and thousands of rounds worth of ammunition.

Just ask yourself how many posts/discussions you see regarding "bedding being shot out. . ."

Your at the mercy of the folks who made the stocks.

I'm not. That's what $100K in software, a CNC mill, and 20+ years experience allows me to avoid. Divine power is nice to have at times.

I didn't get to this process just for the sake of being different.

It may also be total bullshit because I've never taken the time to actually try to measure it. I doubt it though because my indicator tests during final inspection never go past .0005" on the dial.

The final proof is in the pudding and a prone gun holding a .27" C/C group at 100 (first 5 shots out of the thing while fire forming) and 1/3rd minute elevation at 600/1000 tells me I'm obviously not hurting anything.

Formal education certainly has its place however its rarely superseded by experience. (almost never)

Have a great weekend all.

Back to work!

C


PS:

At $20 bucks a can, the mold release agent I use is some of the best stuff in existence. Mirror image castings aren't a problem.

You'd also be wise to heed 300's words as well. He's a perty smert feller.

 

[Keith Johns]

Re: The Importance of bedding

And that is an amazing stock.

I know youre better/more experienced Dixon. I figred you coated before bedding. Thought everyone did. Guess not. Wouldnt have brought it up if I knew you did different.

I agree with ya that every .001" matters in bedding, more so I guess if youre removing material rather than adding it.

 

[BradfromND]

Re: The Importance of bedding

Chad, I couldn't help but notice the caliber on that one.

Can't wait for mine to get here. The brown truck cant come fast enough.

 

[former naval person]

Re: The Importance of bedding

"very visually detailed person"...wonderful way to describe "very picky OCD". (Smile)

 

[LRI]

Re: The Importance of bedding

Cookin!

On a different/related note:

Here's a funy one!

This will eventually be a Terry Leonard redwood/carbon BR stock. I'm building this on a Turbo Rimfire action for a client who takes his 22's quite seriously.

I ordered the stock as a "blank" so that I can be beyond a doubt certain everything is exactly square/symmetrical with the world.
Terry's stuff is surreal. A real treat to get to work with.

Here she is bedded and with a carbon inlayed barrel channel. This one is ready to go back for final contouring.

Fun stuff.

 

[LRI]

Re: The Importance of bedding

Here's one of his rifles I did for him last year. Stolle Swindlehurst 22LR BR gun:

Recoil pad:

Virgin McMillan BR Edge stock:

Paint applied, color sanding finished and ready for clear:

 

[STR]

Re: The Importance of bedding

That's really nice!!!!

 

[Keith Johns]

Re: The Importance of bedding

You really do amazing work sir.
Ive already had a rifle come through here that you barreled and fluted. It was as good as any Ive seen anywhere.

Ive made two stocks from English Walnut blanks by hand, and one Mcmillan flat top done on a manual mill. Yours look better than mine did that's for sure.

Very impressive

 

[phideaux]

Re: The Importance of bedding

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Funny.

I always coat barreled actions after bedding them and they assemble/shoot just fine. </div></div>

as do i. </div></div>

same here....i only bed rear of lug, i see no reason for any other part of it to touch....unless your rifle recoils forward, to the sides or down and i don't think thats goin to happen.

 

[Keith Johns]

Re: The Importance of bedding

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: phideaux</div><div class="ubbcode-body">
same here....i only bed rear of lug, i see no reason for any other part of it to touch....unless your rifle recoils forward, to the sides or down and i don't think thats goin to happen. </div></div>

I bed the rear and front and relieve the sides and bottom. I see no harm in bedding the front, and can think of a positive or two.

Its a tight fit front to back. The lug will always be against the rear. And its probably an especially good idea to do to rifles bedded for the first 1.5" or so of barrel.



And that's one nice/expensive .22!

 

[phideaux]

Re: The Importance of bedding

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Keith at PCR</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: phideaux</div><div class="ubbcode-body">
same here....i only bed rear of lug, i see no reason for any other part of it to touch....unless your rifle recoils forward, to the sides or down and i don't think thats goin to happen. </div></div>

I bed the rear and front and relieve the sides and bottom. I see no harm in bedding the front, and can think of a positive or two.

Its a tight fit front to back. The lug will always be against the rear. And its probably an especially good idea to do to rifles bedded for the first 1.5" or so of barrel.



And that's one nice/expensive .22! </div></div>

if your screws are torqued properly the action won't move. doesn't really matter how one does it as long as the results are good on the target.

 

[SgtKope]

Re: The Importance of bedding

I have a dumb question on bedding:

With the new aluminum stocks (i.e. XLR, McRees, etc) I know they don't "require" bedding but would you still reccomend it? Also what bout stocks with an aluminum channel (HS Precision)?

 

[LRI]

Re: The Importance of bedding

Was able to sneak down to the shop for a couple hours this morning.

Couldn't stand looking at "ol girl" sitting there all slopped up in resin so I decided to get a head start on the makeover.

Hopefully this will exorcise the 9 ring demons out of this bugger.

All that's left is to spot the pillar holes, machine the trigger well, and assemble. I'd do it now but I have my 4th axis setup for engraving barrels. I loath moving that thing around so I'll knock those out first, then finish this up.

As you can see the pillar spots were retained. I'd hoped they'd mask/hide a little better but this isn't bad. It shouldn't hurt performance at all since it was contoured the action already and the minor dimensional change was made up with the new resin during the cast. Overall not too shabby for a "repair".

Going well!

Enjoy your Sunday Germs.

C.

Before:

Present:

 

[eddief]

Re: The Importance of bedding

Bottom line is it's best to bed after coating if you have the means, takes the middle man right out.

If you are farming your coating out, then yes as long as you taped the lug correctly when you bedded you shouldn't run into any problems with fitting, as long as your coater is correctly spraying.

Bed a lug tight (no tape), then coat. You will have problems with a tight fit, guaranteed. Some folks just don't use tape.

A big contributor to all this, is we generally are bedding and coating round Rem type receivers for the most part. These are much easier to deal with.

Bed up a Stolle Panda with no tape anywhere, have it coated with cerakote and then try and drop her back in. It won't do it, period.


So my final answer still holds. I prefer to bed after coating, but I do my own coating.

Always more than one way to skin a cat and in the end it's still a skinned cat.

 

[LRI]

Re: The Importance of bedding

Well the bedding job "remix" worked.

checked out at .0002" on both screws.

Well inside of the mess it was prior. So were boxing it up and getting it heck outa here so he makes his match this weekend.

Here's the before/after.

Before:

After:

 

[lw8]

Re: The Importance of bedding

Chad-

Are you turning out wood stocks from blanks? I didn't see that offered on your website. Just wondering...perhaps you have a stock duplication capability? I have a couple of older rifles that could use some new wood to replace the older oil soaked beat up factory stocks and gunsmiths that work in wood (competently) are a bit hard to come by these days.

 

[LRI]

Re: The Importance of bedding

Send em in.

CNC stock making isn't a problem.

C.

 

[mdesign]

Re: The Importance of bedding

Good looking work there Chad. CNC can do some amazing things.

 

[lw8]

Re: The Importance of bedding

Awesome to hear that you can turn a wooden blank into a finished stock.

When you get a minute, can you PM me some general ballpark pricing for your stockmaking work (shaping, inletting, finishing, checkering, etc). I can supply the blank...just need a skilled smith to turn it into a finished product.

Thanks!

 

[Keith Johns]

Re: The Importance of bedding

Mr. Dixon, or anyone else, how do you feel about having two or more areas oppose recoil forces?

The recoil lug being one, and the other being anything... the rear of the tang, an action screw, or even a bolt handle touching the stock.


I can see how having anything opposing recoil force(axial force) besides the intended area(recoil lug) may effect accuracy or POI.

Ive assumed that to be a rule and I think its a safe one to follow for an accurate and consistent POI rifle.

Im curious what others think about it.

 

[LRI]

Re: The Importance of bedding

Stack a line of people in a bus and slam on the brakes.

Your gun does the same thing in recoil with multiple lug surfaces.

Really bad w/ repeaters in spaghetti stocks chambered in magnum calibers.

Single shots-not so much.

Bolt handles should never touch the stock. That's amerture night for sure.

Isolate recoil to one surface whenever possible is a good rule of thumb.

 

[Keith Johns]

Re: The Importance of bedding

So when you have an action that by design has area other than the lug opposing recoil force, I assume just tape it off so there's a small even gap? Is that what is in the pic near the top?

Some Mausers for example, the tang is inlet into the stock, and takes recoil force if its not relieved. Might sound crazy but if you had a guy that wanted the utmost accuracy from his Mauser, would you relieve the tang so it's not taking any axial force?

 

[LRI]

Re: The Importance of bedding

Place your hands as if in prayer. Keep your palms/fingertips touching one another. Now bend at the knuckles so your hands part in the middle.

This is essentially what happens with a repeater in recoil. The sides of the stock bow out as the recoil lug transfers the energy to the stock. It's your "first" recoil pad so to speak as a significant portion of the energy generated is absorbed here. The remainder travels down the stock through the grip and on to your shoulder. We know this to be true because when we look at gross examples (big bore dangerous game safari rifles in wood stocks) we see the stock cross pinned ahead/behind the magazine box. Why is that?????

An interesting point to consider is whether its better to transfer the recoil here or through the tang of the receiver (on actions that have a good deal of surface area back there)

I've played with this at length. It does work but the conditions need to be right. A 22-250 I had was done this way. The tang was the "lug" as it was a large BR heavy style tang. The rifle shoots scary good. .098" groups@100 with factory ammunition.

One rifle doesn't tell the tale as it could just be a fluke, but I've done a few this way and the results have been pretty consistent. I suspect calibers has a lot to do with it. I personally wouldn't try it in a big magnum as it could very well break the stock.

Rule of thumb, isolate one surface as the one to transfer recoil. Ensure it has sufficient surface area to reliably transfer the energy safely. (meaning it won't fatigue/crack/break something over the long haul)

Pillar holes should be oversize, peripheral features in the stock should also be dealt with.

Winchester actions present interesting challenges as you have the back of the trigger boss, the trailing edge of the mag mortise, etc. Those should all be masked off imo. There's no need to "grunt" an action in/out of a stock. in the grand scheme of things it does more harm than good.


One topic I personally find interesting is the argument of flat bottom receivers over round actions. I've not seen where one clearly outshines the other. In the safari game your a chump if your rifle isn't built on a flat bottom action. It's essentially a 10 commandment. I personally challenge this because if I were negotiating a deal with a client for a big magnum (say 338LM) for a 1K yard bag gun I'd likely suggest a round receiver from any of the marquee action makers. It would never occur to me to build it on a Dakota 76, Stuart Mauser, or Winny CRF M70.

I'm guessing 99.99% here would arrive to the same conclusion. Yet if we take that same gun, lighten the barrel contour, stuff it in a nice piece of wood, and go to Africa, we'd be looked at cross eyed by the guide and the other guys in the camp.

As with many things in "gun world" I don't get it.



Hope this helps.

C.

 

[Mister Ridge]

Re: The Importance of bedding

Is it possible to re-use a stock that was bedded to a different action?

 

[Jrb572]

Re: The Importance of bedding

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RidgeAve. Rifleman</div><div class="ubbcode-body">Is it possible to re-use a stock that was bedded to a different action? </div></div>

Yes you just have to grind the bedding compound and re-bed for the different action.
.

 

[Mister Ridge]

Re: The Importance of bedding

So far I tried to use a file to remove material to get the action to fit.It is a snug fit but so tight as to be hard to remove.Will this work somewhat without breaking or damaging anything?

PS. not building a benchrest rifle.

edit:I meant to say not so tight as to be hard to remove.

 

[LRI]

Re: The Importance of bedding

There's no difference between bedding a BR gun (ignoring glue ins for the moment) a tac rifle, or a common every day can plinker.

Bedding is bedding. It should be a tension free casting/register for the action to sit in. If it's not then your only fooling yourself. Some rifles are inherently more sensitive about it than others. Rimfires for instance are quite fickle. This is because you have a horrible cartridge traveling 1/3rd the speed of any modern centerfire. That means 3x times longer in a given length barrel. Lots more time for crazy chit to happen.

If a rifle strings vertical and your standard deviation is under 10fps, you have known good optics, then it's likely your bedding is in need of attention. In the case of this rifle it didn't string vertical, it started walking left/right in a saucer shape. Since it pounded the X ring prior to the bluing fiasco it was pretty cut/dry on what was happening. Just wiggled back and forth in the stock. Enough to start catching the mid 9 ring at 1K yards.

Hope this helps.

C.

 

[LRI]

Re: The Importance of bedding

From an email I received yesterday:

I guess we "fixxed on it."

<span style="font-style: italic"><span style="font-weight: bold">"Not much wind. Temps. about 75 in the morning 82 by afternoon. Rain storm blew in and out quick during the last string.

1st. string: 198-14 Fireform loads Berger 105 VLD

2nd. string 198-10 Fireform loads Berger 105 non VLD. Never had much luck with this bullet but had 25 of them laying around so I used them up.

3rd. string 198-10 Match loads Berger 115 VLD. Wind had come up and the light was very bad .

I took 2nd. place overall. Nice to see 2 guy shooting sling and irons in all 3 matches take first and second. Glass in allowed in two of the three matches at this club. I am going to explore the Berger 105 VLD's a bit more. All in all I am very happy with how the gun shot, all 9's were my fault.

John"
</span></span>