Sniper Country Duty Roster collective wisdom


Technical - Bedding an Action:


Some of you guys, like Al O., are gunsmiths. Tell me if this would work. Receiver flexion seems to be somewhat of an issue from time to time. Why can't you start with a big diameter barrel blank and turn down about 3/4ths of the length to the muzzle to a normal diameter. Cut the receiver threads and chamber. Mill the breech quarter so that there is still a lot (I mean a big chunk) of metal on the underside of this section of the barrel. The top half of the barrel would appear normal after removing enough of the extra metal up there. Now drill and tap the extra metal on the bottom side of the barrel and remove any excess you don't feel is necessary. This extra metal is now your bedding surface. Screw on the action. Stress relieve the barreled action and pillar bed the barrel to the stock, leaving the receiver free-floating. The recoil lug would be huge. It seems like you would have many times the bedding surface and the joint between the receiver and barrel would not have to resist the same recoil forces as when the receiver is firmly attached and the barrel floats. Barrel harmonics? Try a BOSS-type attachment if necessary.

Paul J. Headlee <pheadlee@networksplus.net>
Ogden, KS USA - Thursday, November 12, 1998 at 17:42:16 (EST) 


To Paul: barrel bedding
A bedding method similar to the one that you described has been used to win the National Matches at Camp Perry. The only difference is that a bedding sleeve was made then slid on the barrel and glued in place. The receiver was then free floated, there was a big write up in American Rifleman a few years ago on exactly how to do it.

Steve <nato@bright.net>
S.C.D.H., Ohio USA - Thursday, November 12, 1998 at 19:12:27 (EST) 


Bedding; How do I do it? I've heard what to use and how it effects accuracy but what is the point? To cut out all of the possible wood touching the action only to be supported by devcon supported by the wood!? Does the bedding material need to be in full contact with the entire action or is it good enough to have just the screw sleeves contacting the action and nothing else.

tom <tom.scott@lmco.com>
here there, & everywhere USA - Saturday, November 28, 1998 at 12:00:16 (EST) 


Tom: bedding
The purpose of bedding the action is to get a better fit than possible with a wood chisel. The goal is to bed the action in such a way that there is no stress or twisting when the screws are tightened.
Different gunsmiths may bed a little different from one to another but most think that the recoil lug should be bedded, the area directly under the screws front and back should be bedded and the middle part where the cartridges feed thru should have clearance. Also the first couple of inches of the barrel under the chamber should be bedded to take some of the hanging weight off the receiver.

Steve <nato@bright.net>
S.C.D.H., Ohio USA - Saturday, November 28, 1998 at 19:27:40 (EST) 


Bedding: Now let me see. Steve, I completely agree with about complete bedding of the recoil area, and fore and aft, but the barrel channel I completely free float. An "easy" way of doing it is to put at least two layers of electrical tape going in the direction of the barrel. Put two layers on and use a rezor to remove any excess electrical tape around where the barrel is threaded into the receiver. Cover the complete barrel, cover all metal and taped parts with at least two coats of release agent. (Remember at least two coats.) Let it dry! and the place the bedding compound at the appropriate location. When it sets up and is almost cured (usually about 24 hours later), pop the barrelled action off and then using a barrel rasp., open up the barrel channel slightly. Remove the layers of electrical tape and you have a perfect fitting barrel that is also a free floater. Its not the only way to do this but it is primarily the way I do it.

Thank you for listening

al
Al Ostapowicz <aaostapowicz@worldnet.att.net>
I was Gone, But I'm Back Again in the Provincial Dictatorial State of , Ohio USA - Saturday, November 28, 1998 at 21:18:55 (EST) 


Re: Block or block type bedding (long)

Paul,
Saw your Nov. 12th , 1998 posting and thought that I would add a few thoughts on the subject. Others may not have heard of these techniques, …..or thought your thoughts.

Concerning the enlarged area at the rear of the barrel. I'm sure it would work, but getting it into play is another story. A lot of odd machining; …plus having an unequal amount of barrel steel around the bore may show up when the barrel heats.

Part 1, Overview:
Our rifle actions are not very good at supporting long heavy barrels due to the various cuts made for the ejection port, magazine well and trigger opening. There are various friction points in normal bedding which can stick when an action flexes during firing and prevent the action from returning to its former position. If it doesn't return each and every time then, inaccuracy is the result. Hard to describe this in print with few words. With block bedding, you can rule out this one big variable (the action floats), and you are left with only barrel and bullet quality to deal with. As a secondary benefit, by moving the bedding closer to the muzzle you are effectively shortening the barrel length. A relatively limber 25 inch barrel becomes a very rigid 17 inch barrel and this is always welcome. David Tubbs won several High Power Championships using this technique of bedding.

Part 2, Types of block bedding:
Type 1.) The first is to epoxy a properly bored aluminum tube (sleeve), 1.500" in diameter to the roughed up and degreased large end of the barrel. Drill and tap the underside with .250 by 28 tpi diameter holes and bed this sleeve into your stock making sure that the action, magazine, barrel, and recoil lug float. The rear shoulder of the sleeve will provide your recoil lug. When bedded this way action rigidity is a non issue and its only function is to hold the firing mechanism and bolt. It would simplify the process to have the large end of the barrel cylindrical in shape for 6 inches or so, before the taper started. I have bored an internally tapered sleeve and it was not a pleasant experience. The hole being tapered, small diameter, and six inches long. Double ear protection was needed because tool chattering occurred. This sleeved barrel was bedded into a wood 40-X stock which had been milled out to a shell in the desired sleeve location. A couple of pounds of Devcon provided an inert and strong area for the sleeve to lie in.

To forestall any question about the integrity of the sleeve/barrel bond, let me say that my partner and I once fired back-to-back Leech Cups on a hot August day. This is about 60 shots with a .308 Win. I did not rough the surface of this barrel, but only degreased it. The barrel/sleeve joint held fine. I admit to getting a queasy feeling midway through the second string concerning the said joint. My partner was shooting his first 1000 yard match and I didn't want anything to go wrong.
Safety was not an issue as I had left the receiver ring screw in as a back up. The screw itself touched nothing on the stock and only provided an emergency "stop" in case something went wrong.
The only downside I found to my block bedding was that when bench shooting I could detect a slight crosshair movement as I was pulling on the 4 lb. trigger. It wasn't very much, perhaps 1/8th minute or so, but it was very obvious with a 24X scope (action mounted). Pulling the trigger was actually causing the receiver or stock to bend. Hard to believe, but it is true. I went to a 2 oz. trigger and that solved any problems with flexing. The scope should be mounted on the block to alleviate this phenomena.

Type 2.) Another way to block bed is to use a square block. It is bored out to the barrel diameter and then drilled and tapped for several screws on each side. A slitting saw is then used to cut the top half off. The barreled action is then clamped into the split sleeve. There used to be some concern that the clamping would slightly distort the bore diameter, but this turned out not to be an issue.
Type 3.) In the early 1970s BR people would glue a section on the barrel directly into the stock. This method won many benchrest matches back when they were shooting 1/4" groups or so.

Type 4.) I use a Zelenak all aluminum stock which beds with a split clamp around the front action ring. Everything else floats. These have been sold for quite a few years for high power competition. Milosovich (long range shooter extraordinaire) uses one in official Palma competition. It has an adjustable buttstock, adjustable cheek piece, vertical hand grip, squarish ventilated forearm.

This about drains my brain of what I know on the subject of block or block type bedding. Please excuse my bandwidth use, but it was necessary explore this little known subject. Each paragraph could have been expanded to a full page.

Ron N. <rcn8@accnorwalk.com>
USA - Saturday, December 19, 1998 at 00:44:18 (EST) 


Pillars, what possible difference could STS vs. Aluminum be? Weight (measured in grains?) Both should be basically impervious to load compression at 65 inch pounds, Corrosion resistance? A most awesome Doubtful-Dude! The use of aircraft grade aluminums gotta be about equal for internal bedding applications and vastly easier on tooling to machine/final fit. Added cost?: Duuudde!

Most Dudely Mike, look at surfboards and their inner workings for true enlightenment. (non-California talk: get a H-S Precision)

peteR <PNGREIFF@AOL.COM>
WRAPPING PAPER CITY, BY-GAWD USA - Saturday, December 26, 1998 at 10:36:25 (EST) 


Mike: Sorry about our lack of wisdom. However, if you want to read a good article about pillar bedding, contact Brownell and ask them to send you a copy of the Spring 1998 issue of BenchTalk. It goes into specific detail about correct pillar bedding and aluminum vs SS. Guess I'll have to take the Military's Sensitivity Course again. Most times humor coupled with good instruction is the best teacher.

al
Al Ostapowicz <aaostapowicz@worldnet.att.net>
South of Lake Erie, Ohio USA - Sunday, December 27, 1998 at 02:00:23 (EST) 


Sarge and all the others : MY preference in stocks leans towards a laminate and the reasons go all the way back to the 70's shooting for Unc Sam. At Ft Bragg , we had M-21's with both fiberglass or laminate stocks and I seemed to shoot better with the laminate. Then again my shooting may have been tainted by the first fiberglass '21 having a ruined bedding...like taffy from someone letting solvent get in !!! The laminates also looked better !! Later on I shot on two other Post teams and I always Went looking for the laminate stock because (TO ME)I shot better.
That being said.....I currently have a Rem 700V in laminate and will soon have my grubby (though sterile) paws on a 700VSSF !! My plans are to swap the stocks...I have a shooting partner that has the PSS and I plan on looking at the differences between the PSS and the VSSF stocks. I would just like to find a quality laminate stock that is readily available, I'll do the bedding myself. Is there ANY any specific justification for SYNTHETIC ???? Interested shooters want to know!!
OUT HERE
Will <willadams@mindspring.com>
USA - Sunday, December 27, 1998 at 10:28:06 (EST) 
Duuuudes,
The only thing I can say about the laminated stocks is that they have to be bedded just like a fiberglass one. Why take a step back in technology when HS stocks are out there. I know some of you guys just like to play with gooey gloppy shit or with the pillars and bed your own which is cool. Unfortunatley there are guys out there who claim you don't have to bed fiberglass stocks. Billy Martin used to claim that his McMillan made LOD stock was a direct drop in. NOT. WHen you read his ad on the LOD rifle it mentions pillar bedding but I think thats only for the stock on the complete Sako actioned rifle. Buy the stock by itself and you don't get the pillars. I was talking to Bruce Robinson about this and that was how his LOD stock arrived, minus pillars. Decent LE stock but it has to be bedded somehow or like as Mr Bullet says you will crush it and get a bunch of fiberglass dust under the action as the stock material deteriorates. We put a M24 action in it without bedding as per Mr Martins instructions and it shot good. When I took it apart it had glass dust all under it. Not good. Failure waiting to happen.

Why screw with it? With the HS stocks you get a aluminum block which requires no bedding, aluminum through the forestock for the sling swivels to attach to, and no swelling under high humidity conditions (although most properly treated laminates are swell free too).

gooch <kdgooch@aol.com>
USA - Sunday, December 27, 1998 at 12:07:01 (EST) 


Re: HS Precision aluminum bedding blocks (longish)

To all,
There are valid reasons to bed the aluminum Vee type blocks. I'm going to repost a couple of my old writings on the subject(not verbatim), even though it has been covered before on this forum. Older members here will most likely remember bits and pieces.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xxxxx,
Let me give you my 2¢ on aluminum bedding blocks. I'm quite certain that the bedding blocks are perfectly machined on top because they are done in a single step by a precision manufacturer. However, our rifle actions are machined in their annealed state, and then heated and quenched. Of course distortion takes place and the action no longer is straight and true. A skim coat of epoxy is always a good thing to straighten up this mess in this case.

Many years ago in Precision Shooting Magazine someone asked Remington why the 40-XBR action didn't have roll impressed markings on the side. (They are etched or something similar.) Mike Walker (father of the 722,721,700 line of rifles) said that they are finish ground on the outside to true them up with the centerline of the bolt hole and it was because of heat treating distortion. The article hinted that it was quite a problem and needed to be solved. I'm pretty sure that only the receiver ring is heated inductively before quenching. The grinding is after hardening. The article was long ago, so don't quote me concerning the exact details. Something to think about.

Steel custom/benchrest actions are normally heat treated before any machining. Tough on tooling, but the results are near perfection.
------------------------------------------------
xxxxxx,
If it was my rifle, and I wanted to see if the action matched the V-blocks correctly, I would use the old benchrest technique with a dial indicator.

Let me explain. What I do is to position a dial indicator on the barrel at the end of the forestock and have its stem touch the underside of the stock where the bipod would be located. The rifle will be in the vertical position with my hand around the receiver and stock. Then I loosen and retighten the action screw under the receiver ring and watch for movement on the indicator. What I want to see is no more than .0015" or .002 of an inch movement at most. If everything looks good here, then I do the same to the rear action screw looking for the same amount of movement.

If you see more than .002 or .003 of movement that means that you are stressing your receiver to fit the stock. If you don't see any movement at all, that too is a bedding fault, and means that the action is constrained; and that is not what we want either. So keep movement between .0005" and .002" and you will have a good fit.

Actions wiggle around when a shot is fired, and you want them to "float" back to the exact position it was previously. Only in a perfect bedding condition will this happen.

One of the most critical bedding areas is the recoil lug fit. We know that stock recoil lugs need to be surface ground to get rid of thickness anomalies. Also, the front of the receivers need to be lightly faced-off to true it up with the centerline of the action. So if you have a stock Remington I would almost bet that the recoil lug is not perfectly vertical from the side view and not at perfect 90° angle to the centerline of the action from the top view. Most likely it is only partially bearing on it's vertical bedding surface.

This is just "food for thought", and that is enough for one night.
Ron N. <rcn8@accnorwalk.com>
USA - Monday, December 28, 1998 at 00:57:05 (EST) 


Ron N
I agree with you 100% on what you say. I have taken stock rifles and loosened the front screw and had it lift up out of the stock like a Cobra out of a basket!!! After bedding the action they always shot better and more consistant. H& S however does not recommend that you bed there stocks for what ever reason, but I have bedded all mine and with great results. I use the Devcon Plastic Steel and I believe its probably impervious to solvents too. I have had my old 308 bedded for nearly 10 years and it has been in and out of the stock many,many times and until the barrel finally went, it shot great. On the Shephard scope, forget it, its a great idea but after 600yds the circles are all so close in size its to hard to distinguish between them for the correct distance. The eye relief is another bad problem on the mags you will get kissed on the forehead.

Pat <mrbullet@hotmail.com>
USA - Monday, December 28, 1998 at 01:25:51 (EST) 


peteR,
Dude....What I found the problem was is most of the time the bedding block has one or more high spots in it and a little work with a Dremal will take care of this. Its usually the area around the safety or where the bolt is. When this area is ground down the action will fit in the stock a lot better. You can usually look at the underside of the action and see where the marks are on the action from the bedding block coming into contdact with it. I seen a 25-06 so bad that the bolt was starting to drag, now thats definately a bound up action!!! After cleaning it up the gun went from plus 1" to .6 and .7s with no other changes. I hope this answered your question if not try me again and I will try to confuse you some more(HA)

PAT <mrbulllet@hotmail.com>
USA - Monday, December 28, 1998 at 15:18:30 (EST) 


Stocks:

Some posts of late seem to be stockish in nature. HS Precision? McMillan? Laminant? Well,seems like a good subject. Of course, I'm not an expert by any stretch, but here's what I've done so far, and I'll certainly do more when I'm less financially challenged( can anyone relate?).

My 308 stock is a SA HS precision M24 style that's been bedded over the alum. block . The whole rifle was done by K & P. I've removed it from the barreled action a couple fo times to try and look at that *^&%*#& feeding problem. It ain't fixed, but I digress. Upon returning it to 65 in-lb w/ wrench, it shot exactly the same.The bedding was to give better action to stock fit as I've been told that the alum. blocks will sometimes not fit quite right, and can flex somehow. A bedover w/ devcon or marinetex, done properly, will correct this, I'm told. So that's what i did.

The 260 is bedded w/ devcon in a McMillan A2. It was done by Hook Boutin. He prefers opening up the action screw holes and filling w/ devcon to creat devcon "pillars" I suppose. He is generous w/ the devon, and claims this, if done properly, will make a durable and strong stock to action fit. I trust his wisdom on this. The rifle is now nice and heavy and shoots great.

The 6mmBR is devon bedded , by Hook, in a Richards Microfit laminant stock. I did multiple sandings, tung oilings, and steel woolings with idea in mind of taking care of the laminant. This rifle still needs load testing to see it's accuracy.

So, there it is. Three diff. approaches. How wishy washy can a guy get? Why these different ways? I don't know. Just seemed good at the time. I can't prove it but the HS and McMillan stocked rifles seem to be right sturdy. I kinda like the A-2 configuration as far as holdability (ergonomics) a little better than the HS at this point.

Jeff A.
Jeff A. <d1k2l3@aol.com>
Atlanta, Ga USA - Monday, December 28, 1998 at 21:00:56 (EST) 


Bedding with JB Weld
I recently re-bedded my stainless 26" varmint 308 with JB
and I found that it was a lot less runny than Plastic Steel
[it does't run down the barrel channel as bad]. Be carefull
of what you use as a release agent: Brownell's spray works well.
I once repaired a 2" x 6" hole in the transfer case of my
4x4 suburban with it (JBl Weld) and it is still leak free.
Merlyn <Merlynh@dtgnet.com>
Pierre, sd USA - Saturday, January 02, 1999 at 15:43:49 (EST) 
Fantastic site, I visit often. Has anyone out there heard of bedding the first 1 3/4 inches of the underside of the barrel on a sniper rifle? The U.S. Marines do this on their M40A1's as well as the folks at Texas Brigade Armory. They call it a barrel pad. Mike Lau says in his book that this is done because the Remington Action can flex a few thousands because of the weight of a heavy barrel. I was told by a friend in the USMC that Remington actually did a test long ago and found that they acheived the best accuracy from the M40A1's when bedding the first 1 3/4" of the barrel. I am currently building up a rifle with a McMillan stock and I'm considering having it bedded this way. I'm a little worried about barrel harmonics since I've previously read that nothing should touch any part of the barrel.

Pat <Autothority@Erols.com>
Ashburn, VA USA - Tuesday, January 05, 1999 at 19:16:42 (EST) 


Pat,
There are several schools of thought on bedding actions. Some bed out under the barrel and some don't. I like to bed under the barrel for an inch or two with the heavy barrel's because I believe that the heavy barrel can put a bind on the action. I also only bed the recoil lug area and the rear tang some people bed the entire action. I leave the area between the front of the action and the tang "Free floated" and this is a lot the same way an action is when its pillar bedded. It sets on the area of bedding at the screws and the rest of the action is not touching anything. I have found no difference in accuracy doing it one way or the other with a pad or with out a pad. I think if you have a good job of bedding and you have a good rifle it will shoot better than most of us can hold it. The Marine Tex is very good bedding materal bu expensive. Devcon Plastic steel works just as well. Hope this helps to answer your question there probably isn't a right or wrong just what ever you smith perfers. Maybe Ron can give you a better answer.
Pat <mrbullet@hotmail.com>
USA - Wednesday, January 06, 1999 at 09:33:08 (EST) 
Pat: I do attempt to bed a couple inches ahead of the lug for the reasons Pat Bullet gave you! but I must say it is almost impossible to tell the difference given that other factors have so much bearing.
I do one thing a little different though. Mr. Bullet seems to bed first whereas I do everything else I can do to stabilize the system before I bed it. I frankly don't know which way is best. I'm sure that Pat's method is faster and results in a good shooting gun quicker than mine. Often I do things that are nullified by the bedding later so it would be hard to argue my method is correct except that I hopefully might find some unknown problem that might indeed be hidden and reduced by the bedding process to the point I wouldn't know about it.
B.Rogers <brogers@elkhart.com>
USA - Wednesday, January 06, 1999 at 10:48:28 (EST) 
Speaking of bedding, has anyone used marine tex to bed a stock before? McMillan uses the stuff exclusively and so does the USMC.
Any comments would be welcome.

Pat <Autothority@Erols.com>
Ashburn, VA USA - Tuesday, January 05, 1999 at 19:16:42 (EST) 


To who asked about Marine Tex and who said it was expensive. It is a great bedding compound and cost $6.00 for 1/2 pint in Calif. That seems cheap to me. You can do alot of rifles with 1/2 pint. A quart is $13.00 and that will go bad before it is used. Mike
Mike M. <DMMDNLN@AOL.COM>
Calif USA - Thursday, January 07, 1999 at 11:33:52 (EST) 
Mike M: Your comments re: MarineTex were right on target. This is an outstanding product that has incredible versatility. I would not hesitate to use it for bedding compound on actions, pillars, etc. The only limiting factor for it in some areas is the high viscosity and its thixotropic (ability to retain form in an uncured state) nature. This can make it difficult to flow and eliminate air pockets depending on where it is applied. It can be filled with powdered metal additives if desired, drilled, filed, sanded, etc. Besides that, it is reasonably priced and available in virtually any marine supply store. Great stuff. Great tip.
Fred Fischer
People's Rep. of, MD USA - Thursday, January 07, 1999 at 13:29:03 (EST) 
Gunsmithing question: what's the difference between standard bedding, pillar bedding, and using aluminum bedding blocks? What are the advantages and disadvantages to each?
Bach Melick <tmelick@monbar.com>
New Orleans, LA, USA - Wednesday, February 17, 1999 at 16:29:11 (ZULU) 
Bach,
The first type of bedding or the standard bedding is done with a mixture called ACCU Glass and basicly you grind out around the recoil lug and the action and lay a layer of "Glass" for the action to lay in, which in turn should be stress free. The problem is that form use and the torquing of the action screw smoetimes the area between the floor plate and the action will start to "crush" and this can cause problems with the action staying tight. Someone then designed aluminum pillars to be installed in the area where the screws go through the stock into the action, thus preventing the stock crush and making for a more stable bedding job. The aluminum bedding block is on the same principal, in that the action lays on an aluminum bed and it can't be crushed by over torquing the action screws. Pillar bedding is thought to be better in that it lasts much longer.
Pat <mrbullet@hotmail.com>
USA - Wednesday, February 17, 1999 at 17:23:42 (ZULU) 

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