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Gunsmithing Level action to stock in glass bedding?

goodgorilla

Sergeant
Full Member
Minuteman
Nov 16, 2013
425
1
Lecanto, FL
In most videos I see people just eyeballing the ejection port on the action and make sure it is level with the stock. In another case a gunsmith told me I need to use a micrometer. How do you do it? Also I am pretty sure you check the level before and after you apply the tape to the end of the barrel.
 
When I'm bedding an action to a stock I pay more attention to how the action lines up with the action screw holes in the aluminum action block. I make sure that he screws are centered both at the top and bottom of their bore throught the block. I'll either wrap the screws (or use alignment rods) so there is little or no gap between the od of the screw and the id of the hole in the block. This will hold the action in the proper "rotation" as well as forcing the action into "fore/aft" level. I can always alter the ejection port at a later time if it's a problem but I don't want an action cocked to the point that the action screws come in contact with the action block.

If boring a stock to add pillars then go ahead and line up with the ejection "port" but it's also a good idea to use the bottom metal to help make sure the action isn't rotated in the stock.

Micrometer???? Why?
 
I'll call the gunsmith back today and ask him about the micrometer. I was planning on using the taped screws to guide the action into the stock, but never having done this procedure, I don't know if the screws are enough.
 
The angle of your dangle is going to be determined by the forward portion of your barrel being centered in the barrel channel + elevating the action to produce a flush fit on your bottom metal.

If this didn't land you where you wanted to be in the ejection area I suppose you could lower or raise the action a wee bit. As far as ANGLE, I'm not sure you could change that too dramatically without it being noticeable in your barrel/barrel channel alignment, which is far more noticeable.

In the end, if all had to line up perfectly, I'd suggest building up or sanding down your stock/show-line to match the bedded action. I wouldn't put $ on the likelihood of your ejection port inlet being 100% parallel with the top of the barrel channel in the first place though.
 
I talked to the gunsmith again, and he didn't say anything about using a micrometer. I'm now wondering if I should tape the front part of the barrel before or after removing the stock material.
 
You can use a parallel on the lug raceways to level the action. ....but the stock is still a wild card on anything that's not flat.
 
Ok just what I have done. Pulled out a sling stud from the front of the stock. Cut a block of wood to use as say a bipod type rest. Run a wood screw thru the hole for the stud into the block of wood. Make the wood say 12" long so the stock is stable and high enough so the top of the stock is flat. Now set this setup on a flat surface like say a table saw cast iron top. Use an indicator to level the stock left to right. You may have to use a shim under the contact point to the wood to get the top square. And its your call if you reference top or bottom as datum. Then confirm that the action and top rail are square. Again use an indicator and place the action on flat surface laying on the rail and indicate the lugs. Ok all is good. Now dry test fit the action in the stock with bedding screws and see if it pulls square. Check with indicator on top of rail or lugs. Rail is easier but go square across so the angle in the base doesn't affect measurement. I have found stocks that the inletting was so far off on the bottom that the action was twisted in the stock and you could see it by the naked eye. I try to get them with in .005 across the top rail not easy. And like mentioned earlier if the stock isn't flat than good luck there isn't anything to square the action to. Hope this is clear.
 
Ok just what I have done. Pulled out a sling stud from the front of the stock. Cut a block of wood to use as say a bipod type rest. Run a wood screw thru the hole for the stud into the block of wood. Make the wood say 12" long so the stock is stable and high enough so the top of the stock is flat. Now set this setup on a flat surface like say a table saw cast iron top. Use an indicator to level the stock left to right. You may have to use a shim under the contact point to the wood to get the top square. And its your call if you reference top or bottom as datum. Then confirm that the action and top rail are square. Again use an indicator and place the action on flat surface laying on the rail and indicate the lugs. Ok all is good. Now dry test fit the action in the stock with bedding screws and see if it pulls square. Check with indicator on top of rail or lugs. Rail is easier but go square across so the angle in the base doesn't affect measurement. I have found stocks that the inletting was so far off on the bottom that the action was twisted in the stock and you could see it by the naked eye. I try to get them with in .005 across the top rail not easy. And like mentioned earlier if the stock isn't flat than good luck there isn't anything to square the action to. Hope this is clear.

very clear. What kind of measuring tool do you use? Micrometer? Only tool I have right now is level level scope leveling tools.
 
very clear. What kind of measuring tool do you use? Micrometer? Only tool I have right now is level level scope leveling tools.

Micrometers are usually used only for measuring diameters or depths. Can't see how anything other than maybe a level or a good "eyeball" would be needed.

Just out of curiosity, how much is already installed in your stock? Pillars? Action Block? Is the stock inletted for bottom metal? Those will be the determining factors in how your action sits in the stock. Even if just the bottom of the stock is inletted for your bottom metal, THAT will be what you have to build on.
 
I use what is called a test indicator and a surface gauge to hold it. A 1" dial indicator and a magnetic base would work. Stick the magnetic base to a steel block that is flat and use that to slide on flat surface. I square the action to the stock with the pillars installed and all bottom metal inletting done. If your pillars are jacked up or your inletting is then that has to be fixed. Once bedded the recoil lug will make sure the action is square to the stock. And I haven't seen a tactical stock yet that is dead strait and true so there is some splitting the difference going on. You want the action level to the stock from front to back you want the barrel to be strait to the sides and the top rail or raceways square to the bottom of the stock . This is just all my thoughts and yes I think it makes a difference. And yes it takes some screwing around.
 
Interesting reading! I never care much about all of that. As long as the trigger is centered in the slot in the guard, it's all good!
 
Micrometers are usually used only for measuring diameters or depths. Can't see how anything other than maybe a level or a good "eyeball" would be needed.

Just out of curiosity, how much is already installed in your stock? Pillars? Action Block? Is the stock inletted for bottom metal? Those will be the determining factors in how your action sits in the stock. Even if just the bottom of the stock is inletted for your bottom metal, THAT will be what you have to build on.

I'm just doing research right now. But my stock is being made by McMillan(a5), which they are modifying to my action, barrel, and bottom metal. I will be using their installed pillars, I will probably have to dremmel them down a little while removing stock material.
 
Interesting reading! I never care much about all of that. As long as the trigger is centered in the slot in the guard, it's all good!

Did you ever see the YouTube video where some guy merely duck taped (or wired) his barreled action to a piece of 'dunnage" and shot some really tight groups? The dunnage was a piece of wood that had a milled slot for heavy steel banding so he use that side for the barrel channel.
 
Saw the video. And yes it did shoot ok. My goal is to have a rifle that shoots in the same spot today and next month. And in any condition. Poor bedding will never let the rifle show its true potential and every time the weather changes so will your point of impact. Is all this necessary? I think so. Others may not agree. If your content with 1moa groups at 100 yrds and never shoot past 300 yrds this is all a waist of time. Just because the pillars are installed doesn't mean there in the correct spot. We would like to think so. Your dealing with one of the better stock makers so odds are they will be correct. And the OP asked how to check if an action is square in the stock I told him my method that works. I don't want to get in a debate of if this matters or not. You will only bed the rifle once take your time and make sure it is right!!!!
 
bedding stock

I level very simlar to the way bertshortmag does. I use the top of the stock in the front of reciever for my datam point to level the stock.You can use parallel[ground bars] and indicator or quality levels parallel method is most acurate but using either method you must level side to side and front to rear in other words the top of stock is level in all directions, it will save some head aches as you go. I like to put a square up the back of the butt for a double check, its done by eye ball but if it is out of wack it does show. Make sure you dont have material touching the bbl any where and seat your action the I go across the rails and the top of stock to the center line of bbl to check action. Like bptactical says go by your bbl not ejection port, your ejection port is 3-4 in long your forarm is 12in if its not right everyone "will" notice its not right!
 
I sent message a little early, I use very small shims to level and just a dab of epoxy to secrure them to keep them in place. As far as keeping your bbl centered I will put just enough tape on bbl at front of forarm to just touch the sides [some times you must shave material instead of shims ,every stock is differnt]. Next check mag well bottom mettal depths, clearance, ect.. adjust things if nesesary. Now I spot bed the action in the tang and recoil lug area, not much just enough to for the action to return to level and alinment every time. Remove tape from front of bbl. Now I drill the holes for the pillars over size so they can "float". I keap the ID of the pillars to bolt size for alinment they are drilled oversize when job is all finished. Next I bed the pillars and then action and floor plate. You can do this all at once or one at a time starting with pillars...this how I go about my basic beding, mystock and forarm renforcing method is more complicated....on the hide you wil find diff methods this is just mine maybe you can incoporate it with ideas from others... hope some it helps....steve
 
I read the post more carfully and i take it Mcmillian is already going to have your pillars already set. If this is the case and they have already inletted or fit your bottom metal your alinment problems are should be null they are a reputable co. and every thing "should" be alined real well.
 
I will review what I have in mind so you guys can show me where I am going wrong. Here are some givens:
1. The stock will already have had the material removed to accept epoxy.
2. The barrel has not received tape on the 2nd contact point.
3. The stock has an installed by pod

I need to find a flat surface somewhere, and if I am going to be so specific with the rest of the gun I may as well use a level indicator to make sure the surface is level. Now I will attempt to level the stock from front to rear by using a level indicator. I can adjust the side angle using the bipod, and front to rear by propping the butt of the stock on something (not sure what to use). Somehow I need to make sure the stock is locked into place. Next I add or remove tape to the 2nd contact point at the end of the barrel, then add more or less tape to make sure the barreled action is level to the stock. Then I can continue with the rest of the bedding, but I need to use the level after dropping the action into the epoxy to make sure it is still level.
 
That isn't how I would go about it. Take the bipod off the rifle. The setup has to be rock solid. If the back of the rifle rests on the recoil pad that isn't good either. Needs to set on hard surface. It could be a block of wood on the pistol grip. If it isn't a hard surface you will never get the think level. Now you don't want the barrel to dictate level you want the action to be level. The action should sit on top of the pillars and be level to the stock. You do want the barrel centered in the stock. Note I didn't say barrel channel because the barrel channel may not be in the center. Measure the outside of the stock to the barrel on each side to get it centered then open barrel channel if necessary.
 
:) :) :)

By the time people go through all the various "setups" recommended I've had my rifle bedded and have been shooting for two or three days.

Just remember, if there is already a pair of pillars installed, the stock is inletted for the bottom metal, or some combination thereof, where and how you are going to mount and bed the action/barrel is already pre-determined.

If you're starting with an "empty stock", no pillars, no action block, just lots of room for bedding compound, then maybe farting around with levels, etc, might make sense.

But if you can't relocate the bottom metal and thus the screw holes, that's where you have to build from.

Some of the best jobs I've seen involve nothing more than a big O-ring around the front of the barrel where it meets the front of the stock (after check fitting to see that there is plenty of clearance), a piece of tape under the last 1/4" of the tang, and then just bedding the whole mess, making sure that the ejection port lines up and the action screws are finger tight in the botom metal. If there are no pillars in the stock yet, get a set and fit them to the action, bottom metal, and stock before bedding. Then Bed the entire assembly at the same time. Use some stock fitting pins instead of action screws and hold the pillars in place by either wrapping the pins with tape or use o-rings that keep the pillars centered on the pins. When you have it all cured, after wrapping bottom metal, action, etc with surgical tubing or elastic banding, when the pins are removed the action screws will be dead center to the pillars with no chance of contact under recoil or heat expansion.

For pins just take some 1/4" rod stock and get an inexpensive 1/4" X 28 die to cut threads on one end.
 
:) :) :)

Just remember, if there is already a pair of pillars installed, the stock is inletted for the bottom metal, or some combination thereof, where and how you are going to mount and bed the action/barrel is already pre-determined.

That's the scenario I am in, but I have a feeling that I should get the right amount of tape wrapped around the 2nd contact point at the end of the stock forearm. Also, I think it couldn't hurt to have a solid level base the stock can rest on. I am starting to get the urge to build the base out of wood. Say a wide long board that has a few other boards nailed into it that are cut and sanded to make a leveled base.

About centering the barrel in the barrel channel: I didn't even think to measure to see if it was centered before centering the action to it. Suppose it is centered, how much tape to I wrap around the 2nd contact point near the forearm? I have this idea that the bore of the barrel should be parallel with the stock, but the barrel contour is not flat or parallel with the stock. These may seem like stupid concerns, but I have several months before I even get the rifle in my hands.

Edit also, feel free to tell me it's the pillar's job to make sure the bore is parallel with the stock. I am still a newbie.
 
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Don't go grinding on the pillars.

In all honesty, I wouldn't bother with trying to make the old pillars work, considering the cost of a new set of pillars or the ease of making a pair, I'd cut the old ones out and start fresh. You will get a better end result and less time/effort invested with new pillars.
 
They will be new when I get my hands on the stock. So then, I should leave the pillar height alone when removing the stock material? On one of Nathan foster's bedding videos, his wife ground down the pillars the same depth as the rest of the material she removed from the stock. Uh, or grind down the pillars then get new ones after bedding?
 
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Let me see if i got this correct. You bought a McMillan Stock, right?

If so I'd assemble the action and barrel in the stock and if everything fits, you have good clearance the full length of the barrel in the barrel channel, then don't $%^k with the pillars. If you're all wrapped up in making sure that you have the right thickness of bedding material here, there, and everywhere, then go ahead and fart around with a dremel but don't $%^k with the pillars.

Last I heard, McMillan has made a stock or two and probably, by now, have figured out how to place a pair of pillars for any given action. They probably use a barreled action as a jig to set them when they bond them to the stock.

I have kids and grand kids that I tell, when they get to this level of "over-thinking", just follow the manufacturer/supplier's instructions.

Now if your stock was something carved out of an old maple tree stump by some "swamp dweller" that sell's them for $75 at gun shows around the boondocks, your concern about all these little items may have merit. For a McMillan Stock? I seriously doubt it.

From where I see it, you're doing yourself some serious brain damage worrying about "micrometers", "levels" etc. You will do your stock some serious damage if you grab that dremel without knowing what you're doing, especially if you grind down the pillars without first just assembling the action/barrel/stock and checking for clearances.
 
Pillars come from the MFG at the length they are for a very important reason. The spacing between your floor metal and action is critical for the feeding and functioning of your rifle, not to mention your ability to operate the trigger within the trigger guard. You or anyone's wife that goes grinding on pillars with what ever is only going to FUBAR those pillars.

Secondly, what is the point of installing aluminum pillars if you are putting glass bedding over them? Pillars are there for stable, vertical load bearing...
 
Secondly, what is the point of installing aluminum pillars if you are putting glass bedding over them? Pillars are there for stable, vertical load bearing...

It's not unusual to bed the rest of the area around the pillars. If you look at the good bedding jobs, depending on whether flat faced pillars or the pillars were radiused to fit the action, they will be free of any bedding material or just a straight line of the metal will show. This will provide additional support to the action existentially making it a more firm mount for the barrel by filling any voids between stock and action. Pillar bedding has its' roots in the need to prevent wood stocks from being crushed under the pressures attained by torquing the action screws. The wood would expand and contract with heat, moisture, or just plain time, and the damping effect on the action would vary, likewise accuracy.

In reality, pillars by themselves are merely large spacers that fit, as you sad, between bottom metal and action. Due to their larger diameter they can be epoxied to the stock. Take a look at some old Mausers or 1903 Springfields. They only used one 'pillar" and it was a small piece of tubing for the rear action screw, installed to keep the tang from burrowing into the stock. The front action screw held the bottom metal directly against the bottom of the action and this big rectangular box magazine kept the whole action from rotating in the stock.
 
Maybe I wasn't clear, I'm familiar with how they work and what they do.

My comment was geared toward what the OP said regarding a video he watched where someone ground down the pillars and presumably bedded ON TOP of them. That is pointless.
 
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If you look at the good bedding jobs, depending on whether flat faced pillars or the pillars were radiused to fit the action, they will be free of any bedding material or just a straight line of the metal will show.

In reality, pillars by themselves are merely large spacers that fit, as you sad, between bottom metal and action.

Agreed 100%
Glass between the pillars and action wouldn't make much sense as....
1. The "spacer" isn't setting the space. It's now spacer + layer of glass.
2. Glass thin enough to lay between the action and pillar is weaker than that pillar, so you're left with a more likely to crack bedding job...

http://www.snipershide.com/shooting...253-m40a3-build-happening-pws-quantico-3.html

How I do it...
 
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I agree with all the last posts. You can still glass bed your action but do not grind on the pillars or shim the action so it no longer is coming in direct contact with them. If you are going to reposition the action the existing pillars need to removed and new pillars set when you reposition the action this is going to require more stock work top and bottom!.....But for right now I wouldn't sweat it, you will likely just need to give it proper bedding job and go shoot it!!
 
An anser for a question you asked earlyier you can remove some material in the pillar area just make sure you leave a couple small contact points, one on each side of each pillar
 
Maybe I wasn't clear, I'm familiar with how they work and what they do.

My comment was geared toward what the OP said regarding a video he watched where someone ground down the pillars and presumably bedded ON TOP of them. That is pointless.

McMillan believes the best way to bed an action is to put bedding material on top of the pillars.

http://www.mcmfamily.com/pdfs/Pillar Bedding_Article.pdf

Agreed 100%
Glass between the pillars and action wouldn't make much sense as....
1. The "spacer" isn't setting the space. It's now spacer + layer of glass.
2. Glass thin enough to lay between the action and pillar is weaker than that pillar, so you're left with a more likely to crack bedding job...

http://www.snipershide.com/shooting...253-m40a3-build-happening-pws-quantico-3.html

How I do it...

My post was meant for the OP, primarily.

As for putting "glass bedding" on top of a pillar, first I don't use "glass". Most don't. Devcon or Marine-Tex is usually the choice for bedding material because of their compressive strengths. Even the new bedding agents are not the "glass" of old but epoxy resins that are filled with various materials that provide the compressive strength.

If you put bedding agent on top of a pillar, especially a flat one, the excess bedding agent is squeezed out and what remains is only in any irregularities of he pillar surface. This provides for 100% contact between the pillar and action rather than a lesser percentage due to the mating surfaces not matching.

Even the "radiused" pillars don't fit perfectly and in some cases it preferred that they don't. The idea being that there are two contact points at the edge of the pillar that center the action when tied in with the surgical tubing and the bedding fills the void at the bottom of the radius.

If you put any Devcon or Marine-Tex on top of a pillar, secure it with elastic, then let it cure, you'll have a perfect match and the epoxies mentioned have compressive strengths near 10,000 psi. Consider that the action screws on a Remington, torqued to 63-65 in/lbs pulls the action down with a pull ~1200 lbs, the bedding agent is more than up to the task.

On the note of YouTube how to bed your rifle videos, you have to have to be real careful which one you decide is gospel. There are a lot of them that are pure bull-crap.

For the beginners, try the videos posted on Midway USA's site or Brownells instructional videos. Those are two sources that have good "bullshit filters" installed. There are others but if I were to run across a video showing someones wife grinding down the top of the pillars, I wouldn't be able to find the Stop and Delete button fast enough.
 
If I was going to let the pillars support a round action, I don't think I would want a flat top pillar that has a narrow N/S contact line. I would want one that provides support against rocking sideways too, like the ones LRI uses.
 
Here is the video:


Nathan foster is a badass, but I am still unclear about the pillars. One thing that confuses me is that the two contact points are suppose to be at the end of the stock forarm, and the tang. If I leave the pillars alone, won't they create another contact point? I have several months to learn about bedding before I attempt it.

I just emailed Nathan, hopefully I will get a response so you guys can read it. Not saying is right or wrong, I really don't know how to go about the pillars right now. I think I will call McMillan.
 
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Your video is one way of bedding your action, not that is wrong but it is not what we have been trying to explain as far as pillar bedding. You want the action supported by the pillars not the end of your forarm as it would put stress in every thing. You need to sit down with somone who is familar with pillar bedding and have them point out the what where and whys with the your stock and action right there, videos are a help but from where you are starting from it is real hard to try to explain in just words here. I'm not trying to nock you in any way, we all started at ground zero I just believe if somone could point out the fundamentals of the mechanics of what your trying to accomplish it would be alot less stressful.....good luck, once you get figured you will do fine!
 
thinking more about your situation and I probabley live a long ways off but I would be happy to look at things with you. I dont know it all, but have built several rifles from the ground up I do all my own bbling, machine work ect.. all my rifles have shot very well and yes pillar bedding. If you would like give me a pm....steve
 
If I was going to let the pillars support a round action, I don't think I would want a flat top pillar that has a narrow N/S contact line. I would want one that provides support against rocking sideways too, like the ones LRI uses.

The "sideways rocking" when pillar bedding is controlled by the action screws themselves and the bedding material you shouls be using in conjunction with the pillars. Pillars pretty much require bedding while "action blocks" can be used without, although most will skim bed them as well.

If you bed flat top pilars with a product like Devcon, they are no longer 'flat topped". The added epoxy/metal putty continues that contact point all the way around the action to the part line with the stock.

If you have a recoil lug with square sides as opposed to one of the "keystone" shaped lugs, you can bed the sides as well. This will add anti-rotation support. If you bed the sides of a "keystone shaped" recoil lug then heat will increase the upward force at that point increasing stress in the action.

Back to the OP, I'm still puzzled why someone would buy a McMillan Stock and then go out to the world of YouTube to figure out how to bed it rather than just following McMillan's instructions. To me that's kind of like buying a Jack Roush built engine and then asking your local shade-tree mechanic for instructions on how to tune it.

Forgive me but the needle on my "Troll Detector" is starting to come off the peg. Getting hard to tell if someone is genuinely asking for suggestions and help or -------
 
I'm just confused because over the past few days I have had people here and everywhere tell me to do completely different things. I'm probably going to do what McMillan says.
 
Just bed over the pillars like Mcm says to do. Use the two point of contact method, headless screws, and don't put any damn bungees or tape around the action while it cures and you will be fine.
 
Just bed over the pillars like Mcm says to do. Use the two point of contact method, headless screws, and don't put any damn bungees or tape around the action while it cures and you will be fine.

How do you propose to hold the action against the top of the pillars while the bedding material is curing?
 
How do you propose to hold the action against the top of the pillars while the bedding material is curing?

GRAVITY. He said the pillars were being installed by Mcm. 1.Tape around the barrel at the end of the barrel channel and 2. the tang touching the stock behind the rear action screw, everything else floats, i.e. 2 points of contact. Tape or anything else over the action induces stress.
 
GRAVITY. He said the pillars were being installed by Mcm. 1.Tape around the barrel at the end of the barrel channel and 2. the tang touching the stock behind the rear action screw, everything else floats, i.e. 2 points of contact. Tape or anything else over the action induces stress.


I've found that an old "exercise band" which is a wide piece of rubber about 6 mils or so thick, wrapped around the action and stock does a better job of creating positive contact at the pillar top/action interface. Maximum "force" is about 5-6 lbs, evenly distributed across the action itself. When working with a piece of steel that has a yield strengths exceeding 100,000 psi, I seriously doubt you could measure ANY stess whatever in any action I've bedded. Now for those that like to torque down the action screws, that's another story.

Like I said, that's what I've found works best for me. I'll often put the bedded action and stock "muzzle down" in a rack so there's no barrel weight on the assembly. I also don't use any "runny" or "Pourable" epoxies to bed actions. Devcon Steel or Titanium putty, period.

Results speak for themselves as the rifles I've done shoot the same on the first shot as they do on the last. Nice and accurate cold, hot, or anything in between.