I have a question on stock bedding. I've talked to several other smiths and a few shooters and as usual opinions seem to vary greatly. When bedding an action to the stock should one bed 2" or so forward of the recoil lug or should you keep the bedding compound behind the lug. I've had some guys say that you'll kill the harmonics of the barrel if you go forward and I've had others say that it will not and that you need the 2" for support of heavier profile barrels. Just wanted to see what everyone here thought. Thanks for the feedback.
Gunsmithing Stock Bedding?
- Thread starter CCA70
- Start date
As defined by Wikipedia. (just to create even more drama that this is sure to stir up)
"The key to an accurate firearm is consistency. Getting everything to happen the same way for every shot is key to producing small groups, and there are a large number of issues to be addressed in achieving an accurate firearm.[SUP][3][/SUP][SUP][4][/SUP][SUP][5][/SUP][SUP][6][/SUP] The keys to firing an accurate shot are a firm but not overtight grip, the ability to get a good sight picture, and a controlled squeeze of the trigger. The ability to manage recoil is also important in heavily recoiling calibers, both to aid in possible additional shots, and to prevent the user from developing a fear of the recoil.[SUP][7]"
[/SUP][SUP]Lets assume for the moment that the bold print is an accurate description. As people, we don't have strain gauges built into our bodies. Sure, we have nerves to provide feedback, but everybody's calibration is a little different. For my example I'll use a shooting discipline I'm familiar with and one that jades my argument in my favor.
Smallbore Position prone shooting. Anyone who's done it, will tell you it's a bitch. Them little 22 shells will humble you every chance they get. This "harmonic" everyone rants about is around roughly 3x longer with a 22LR. Why? The bullet is traveling roughly 1/3rd the speed of anything centerfire that's cool.
So, it's taking 3x as long to get out of the barrel. -Means stuff has more time to screw with it.
We could lay blame to off call shots on ammunition, but I've velocity tested enough premium 22LR ammo to know its good chit. Eley, Lapua, RWS, and the holy grail (old Soviet made "Olymp") is extremely consistent. -so good it borders on the absurd.
With two hands and one shoulder on the gun and our "calibrated" feel for knowing when stuff is right, we break the shot. With experience and natural talent we can predict (call) where the shot went. So, the top .1% of shooters can make a position repeat for the course of fire.
What about us mortals?
There could be an extra lb or ounce of stock well from one shot to the next. Arms/shoulders get sore and positions go to hell. All of this means the loading (compression, torsion, etc) placed on the stock is going to start to fluctuate as the shot string progresses along.
With a pad under the barrel, you have a direct point of contact with the device that has direct ties to accelerating and directing the bullet. If we simulate this by clamping the action to a 10,000lb object and shoot one shot after another while hanging a variety of weights off the barrel we can easily image groups that resemble planetariums rather than little black holes.
So with that, I support that notion that a barrel for a precision rifle should be floated completely. It's how I've done it for over 15 years and it's worked quite well.
Just my humble opinion after building lots of bang sticks.
C.[/SUP]
"The key to an accurate firearm is consistency. Getting everything to happen the same way for every shot is key to producing small groups, and there are a large number of issues to be addressed in achieving an accurate firearm.[SUP][3][/SUP][SUP][4][/SUP][SUP][5][/SUP][SUP][6][/SUP] The keys to firing an accurate shot are a firm but not overtight grip, the ability to get a good sight picture, and a controlled squeeze of the trigger. The ability to manage recoil is also important in heavily recoiling calibers, both to aid in possible additional shots, and to prevent the user from developing a fear of the recoil.[SUP][7]"
[/SUP][SUP]Lets assume for the moment that the bold print is an accurate description. As people, we don't have strain gauges built into our bodies. Sure, we have nerves to provide feedback, but everybody's calibration is a little different. For my example I'll use a shooting discipline I'm familiar with and one that jades my argument in my favor.
Smallbore Position prone shooting. Anyone who's done it, will tell you it's a bitch. Them little 22 shells will humble you every chance they get. This "harmonic" everyone rants about is around roughly 3x longer with a 22LR. Why? The bullet is traveling roughly 1/3rd the speed of anything centerfire that's cool.
So, it's taking 3x as long to get out of the barrel. -Means stuff has more time to screw with it.
We could lay blame to off call shots on ammunition, but I've velocity tested enough premium 22LR ammo to know its good chit. Eley, Lapua, RWS, and the holy grail (old Soviet made "Olymp") is extremely consistent. -so good it borders on the absurd.
With two hands and one shoulder on the gun and our "calibrated" feel for knowing when stuff is right, we break the shot. With experience and natural talent we can predict (call) where the shot went. So, the top .1% of shooters can make a position repeat for the course of fire.
What about us mortals?
There could be an extra lb or ounce of stock well from one shot to the next. Arms/shoulders get sore and positions go to hell. All of this means the loading (compression, torsion, etc) placed on the stock is going to start to fluctuate as the shot string progresses along.
With a pad under the barrel, you have a direct point of contact with the device that has direct ties to accelerating and directing the bullet. If we simulate this by clamping the action to a 10,000lb object and shoot one shot after another while hanging a variety of weights off the barrel we can easily image groups that resemble planetariums rather than little black holes.
So with that, I support that notion that a barrel for a precision rifle should be floated completely. It's how I've done it for over 15 years and it's worked quite well.
Just my humble opinion after building lots of bang sticks.
C.[/SUP]
I always leave a pad under the shank. All my rifles, and the rifles I've bedded that way, shoot.
The guys that mill out the squeeze out build rifles that shoot...i.e. Chad and others.
I really wonder if it makes a difference, one way or the other.
The guys that mill out the squeeze out build rifles that shoot...i.e. Chad and others.
I really wonder if it makes a difference, one way or the other.
To support a couple of inches forward of the lug makes sense to me especially for heavy barrels. On the same hand I've noticed that some of the chassis systems out there (A.I., Cadex, Rem. RAC, and others) all end their support at the lug leaving the barrel fully free floating. Was just curious to see what others thought and if there was any definitive evidence out there one way or the other. I work with two other smiths, one says nope don't do it you'll kill the harmonics, the other says yes definitely support the chamber area to reduce stresses. I also have a friend of mine that's an ex-military sniper who also says to support the chamber. I truly wonder if it makes a difference one way or the other or if one is better than the other?
I have tried bedding the first inch of the barrel and tried not doing it. Both seem to be ok, so I have stopped bedding everywhere but the rear pillar, the front pillar, and behind the recoil lug. Fewer places for dirt to get in and increase the compliance in the action to stock connection.
My vote is for the 1.5in barrel bed in front of the recoil lug (.308 bull barrel). In a matter of opinion of course, the reason to bed a stock is to create a tight syemtrical in relation to the contour/radius of the action to improve accuracy. Addtionally with that notion you would also use pillars to free float the action in the stock avoiding all unnecessary contact, in turn the only points of contact on the action is the pillars. Thus the barrel is completely free floating, until your fire that well place shot and the barrel "whips", on the downward motion instead of it moving radicaly or making contact with an uneven surface it has a perfectly contoured surface for it to fall into allowing the barrel to return to its original position creating mechanical repeatability.
This depends on a couple of variables, the most important being how heavy/long is your barrel and how strong is your action? I wouldn't hang an 1.250x30 cylinder off the front of a Remington 700, but i would consider it on a BAT or similar action that is stronger, heavier, and has a longer barrel tenon..
I routinely spec my custom barrels with a 5 to 6" cylinder if possible in at the breech.
I attach a dial indicator to a jig on the stock, install the barrelled action, put the gu in a vertical position, and read the dial. When I actually start bedding, I get the glue in place, and then shim the barrel between the stock until the indicator is zeroed in the horizontal position with the bedding T-screws lightly tightened. I also work my pillars until the action rests passively on them so if the bedding material starts to soften when the barrel gets warm, I know the action won't move.
I think it was Lone Wolf, now Proof Research, that started this. It was very controversial. Every gunsmith on the planet now has sheets of carbon fiber they incorporate somewhere in the bedding process. As far as "killing harmonics" goes, that sounds like a good thing to me, but more likely you are changing the harmonics, which is one of a myriad of reasons why some guns shoot well an others don't. And as if filial/paternal relationships aren't hard enough to manage, my father insists on full length bedding, won't even consider anything else, says "free floating" barrels are just cheap gunsmithing, an he has a point - when Remington and Winchester started offering "free floating" barrels in the late 60's/early 70s, it was basically to save them money on inletting the barrel channel.
Dad beds his with Acraglas so glass is just over the barrel contour and the barrel snaps into place.. sorry to say, his jobs are brually accurate, but he is only interested in the first two rounds out of the barrel of a hunting rifle. To further muddy thee water, he will only use wood stocks. Gotta love him.
Disclaimer: objects in mirror are closer than they seem, your results may vary.
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I just realized I left out an obvious but crucial step in this bedding process: the recoil lug. The front, bottom, and sides should be covered with two layers of masking tape; only the rear of the lug should be bedded - at least in my world
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