I've heard this mentioned in many articles for precision rifles and was wondering what does glass bedding in a stock actually do. From what I can gather it sounds like it may have something to do with the barrels harmonics perhaps and reducing interferance caused when firing between the barrel and the stock it's fitted to. Please correct me if I'm wrong.
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What does glass bedding actually do?
- Thread starter Kimio
- Start date
When actions are mated to stocks there has to be some room for individual variances between the parts. You never get a perfect fit. By glass bedding you pour a bedding compound into the stock where the recoil lug fits into he mortise in the stock. Some full length bed the entire barrel channel, others just the 1st inch or 2 of barrel. You put a release agent on the action and barrel and reassemble your rifle. After the bedding compound dries you have a perfect fit between barreled action and stock. If your release agent works you can take them apart, if not you have glued your stock to your rifle.
This MAY improve accuracy. As long as it is done right it won't hurt though. I've glass bedded several rifles with quality synthetic stocks that were already very accurate. It helped none, but didn't hurt either.
I think it is more helpful with wood stocked rifles. No matter what you do to a wood stock you will never completeley seal the wood. As temperature, humidity and altitude change a wood stock will expand and contract causing differnt pressure points on the barrel and action. Glass bedding and free floating the barrel minimize the effects of the wood's changing diminsions.
This MAY improve accuracy. As long as it is done right it won't hurt though. I've glass bedded several rifles with quality synthetic stocks that were already very accurate. It helped none, but didn't hurt either.
I think it is more helpful with wood stocked rifles. No matter what you do to a wood stock you will never completeley seal the wood. As temperature, humidity and altitude change a wood stock will expand and contract causing differnt pressure points on the barrel and action. Glass bedding and free floating the barrel minimize the effects of the wood's changing diminsions.
It can also work with synthetic stock - particularly cheap stocks that aren't machined properly. One of my hunting buddies had a brand new rifle that just wouldn't group. Our other hunting buddy (who happens to be a pretty good garage gunsmith) took it apart and found that the factory bedding pillars were misshaped allowing too much wiggle room. A little judicious sanding and a glass bed made the fit perfect. The groups instantly tightened up to where they were supposed to be.
"During firing, the ultraslow-motion video showed that the receiver squirms
and wiggles inside the stock like a snake with its tail caught under a leg of
Grandma’s rocking chair. If the stock bolts are tight and the fit between the
stock and the receiver is precise, the barreled action will likely settle down in
its same relationship with the stock with no ill effect on accuracy.
But if everything is not just right, it may or may not settle in the same between shots,..."
Read more: http://www.shootingtimes.com/2010/09/23/gunsmithing_st_bedarifle_200904/
and wiggles inside the stock like a snake with its tail caught under a leg of
Grandma’s rocking chair. If the stock bolts are tight and the fit between the
stock and the receiver is precise, the barreled action will likely settle down in
its same relationship with the stock with no ill effect on accuracy.
But if everything is not just right, it may or may not settle in the same between shots,..."
Read more: http://www.shootingtimes.com/2010/09/23/gunsmithing_st_bedarifle_200904/
zincwarrior
New member
Excellent question and information!
It makes the stock/receiver connections rigid and rigidity is a key factor in accuracy.
It mimimizes the warping that may occur when wood expands and contracts with changes in temperature and humidity .
I bed the entire receiver and just 2" of barrel. That gives a free floating barrel that doesn' interfere with barrel vibrations when the gun is fired.
It mimimizes the warping that may occur when wood expands and contracts with changes in temperature and humidity .
I bed the entire receiver and just 2" of barrel. That gives a free floating barrel that doesn' interfere with barrel vibrations when the gun is fired.
The key concept is CONSISTENCY. That is essentially what the term "accuracy" refers to - the ability of the rifle to put each round into the target with consistency. Consistency is impossible to achieve if the barreled action of the rifle can move about in the stock. In that circumstance, each time the rifle is fired, the action will move - and not always exactly the same amount. So, glass bedding allows the fit to be as perfect as possible - and shot-to-shot consistency to be achieved.
Whether to free-float a barrel is another matter. Contrary to popular opinion, free-floating does NOT always improve accuracy....and CAN ruin it in some circumstances. As ronz mentioned, pencil thin barrels often do not respond well to free-floating. Some heavier barrels don't either. So don't EVER fall into the trap of assuming that FF is always better.
Free floating should ALWAYS be approached as a secondary consideration. If the action is not bedded properly, then free-floating WILL harm accuracy, period. So, the fit and bedding of the action should be addressed first, always. I always bed the complete action, the bottom metal (such as the magazine box and trigger guard on Mausers, for example).....and the first 1.5 - 2" of the barrel.
After ensuring proper bedding of the action, THEN test to find if FF works best. Pressure point bedding of the barrel, or full-length barrel bedding, etc. just MIGHT work better, in some cases. My Mauser sporter, with a medium - weight short barrel (17.5") does best with rather large pressure point (over 1 sq. inch total) bedding in the fore end. Free-floating produced very much inferior results. This runs counter to conventional thought on the subject, which assumes that a short, stout barrel will work better if FF (with the action properly bedded and a stiff stock, of course). Ain't always so.
I've bedded at least 50 rifles over the years, including full military-stocked ones (like Mausers, for example), complete with barrel bands, bayonet lugs and hand guards (I developed a way to make bedding work in these rifles, very much against "conventional wisdom"). I know of what I speak.
Whether to free-float a barrel is another matter. Contrary to popular opinion, free-floating does NOT always improve accuracy....and CAN ruin it in some circumstances. As ronz mentioned, pencil thin barrels often do not respond well to free-floating. Some heavier barrels don't either. So don't EVER fall into the trap of assuming that FF is always better.
Free floating should ALWAYS be approached as a secondary consideration. If the action is not bedded properly, then free-floating WILL harm accuracy, period. So, the fit and bedding of the action should be addressed first, always. I always bed the complete action, the bottom metal (such as the magazine box and trigger guard on Mausers, for example).....and the first 1.5 - 2" of the barrel.
After ensuring proper bedding of the action, THEN test to find if FF works best. Pressure point bedding of the barrel, or full-length barrel bedding, etc. just MIGHT work better, in some cases. My Mauser sporter, with a medium - weight short barrel (17.5") does best with rather large pressure point (over 1 sq. inch total) bedding in the fore end. Free-floating produced very much inferior results. This runs counter to conventional thought on the subject, which assumes that a short, stout barrel will work better if FF (with the action properly bedded and a stiff stock, of course). Ain't always so.
I've bedded at least 50 rifles over the years, including full military-stocked ones (like Mausers, for example), complete with barrel bands, bayonet lugs and hand guards (I developed a way to make bedding work in these rifles, very much against "conventional wisdom"). I know of what I speak.
4runnerman
New member
If yor rifle is not pillar bedded do that first and see what happens. Bedding is not always benificial to your rifle. If your rifle is shooting good right now,don't mess with it. Bedding can mess up a rifle,even if done right. If it is not shooting good after you pilar bed it,then and only then look at glass bedding it.
It IS possible to both pillar bed and glass-bed a stock at the same time. However, why would you want to do so ? No reason to do this - so, it's generally considered a "one or the other" proposition.
As to which is better - neither. Done correctly, both will produce equal results. Pillar bedding does help somewhat to prevent stock compression over time. This is not a really big issue in most cases, however.
Pillar bedding IS more difficult to get right than conventional glass bedding. More alteration (irreversible because large holes for the pillars must be drilled) to the stock must be done. Mess it up and the stock might be junk. This method also produces more localized stress on a stock. With wooden stocks, in SOME circumstances (such as weak areas of lower density wood), pillar bedding can lead to cracking. For these reasons, I prefer conventional bedding.
I would NOT recommend doing both on the same stock. I would also respectfully disagree with 4runnerman about trying pillar bedding first. As I said, this method is more difficult to get right and can be problematical if one has little or no experience with it. Once the stock is drilled for the pillars, there is no going back (unless filling mis-drilled holes with epoxy or plugs is acceptable to you). Conventional bedding is easier and takes advantage of the inlet areas already existing. As these inlet areas are designed to spread the recoil forces throughout the structure, rather than only through narrow localized portions (as with pillar bedding), conventional bedding tends to put less localized stress on a stock. So, there is a lower chance of inducing cracks, etc.
Often, if the action has a stout, relatively large recoil lug already and if the fit of the action to the stock is good (already), glass bedding can often be limited to the recoil lug pocket (on modern actions) - with acceptable results. (This does not apply to older style actions, such as Mausers, which require more extensive bedding.)
As I said, either type of bedding will produce good results, if done correctly. Oh and I would tend to agree with 4runnerman in that, if the rifle is shooting really well now, it may not need bedding. Most rifles can benefit from some work in this area, but, as I alluded, it is possible to get good results with an abbreviated bedding job, depending on the type of action and the (existing) fit in the stock. It is always best to start small and work up - and this is true of bedding projects as well.
As to which is better - neither. Done correctly, both will produce equal results. Pillar bedding does help somewhat to prevent stock compression over time. This is not a really big issue in most cases, however.
Pillar bedding IS more difficult to get right than conventional glass bedding. More alteration (irreversible because large holes for the pillars must be drilled) to the stock must be done. Mess it up and the stock might be junk. This method also produces more localized stress on a stock. With wooden stocks, in SOME circumstances (such as weak areas of lower density wood), pillar bedding can lead to cracking. For these reasons, I prefer conventional bedding.
I would NOT recommend doing both on the same stock. I would also respectfully disagree with 4runnerman about trying pillar bedding first. As I said, this method is more difficult to get right and can be problematical if one has little or no experience with it. Once the stock is drilled for the pillars, there is no going back (unless filling mis-drilled holes with epoxy or plugs is acceptable to you). Conventional bedding is easier and takes advantage of the inlet areas already existing. As these inlet areas are designed to spread the recoil forces throughout the structure, rather than only through narrow localized portions (as with pillar bedding), conventional bedding tends to put less localized stress on a stock. So, there is a lower chance of inducing cracks, etc.
Often, if the action has a stout, relatively large recoil lug already and if the fit of the action to the stock is good (already), glass bedding can often be limited to the recoil lug pocket (on modern actions) - with acceptable results. (This does not apply to older style actions, such as Mausers, which require more extensive bedding.)
As I said, either type of bedding will produce good results, if done correctly. Oh and I would tend to agree with 4runnerman in that, if the rifle is shooting really well now, it may not need bedding. Most rifles can benefit from some work in this area, but, as I alluded, it is possible to get good results with an abbreviated bedding job, depending on the type of action and the (existing) fit in the stock. It is always best to start small and work up - and this is true of bedding projects as well.
FiveInADime
New member
It IS possible to both pillar bed and glass-bed a stock at the same time. However, why would you want to do so ? No reason to do this - so, it's generally considered a "one or the other" proposition.
As to which is better - neither. Done correctly, both will produce equal results. Pillar bedding does help somewhat to prevent stock compression over time. This is not a really big issue in most cases, however.
Pillar bedding IS more difficult to get right than conventional glass bedding. More alteration (irreversible because large holes for the pillars must be drilled) to the stock must be done. Mess it up and the stock might be junk. This method also produces more localized stress on a stock. With wooden stocks, in SOME circumstances (such as weak areas of lower density wood), pillar bedding can lead to cracking. For these reasons, I prefer conventional bedding.
I would NOT recommend doing both on the same stock. I would also respectfully disagree with 4runnerman about trying pillar bedding first. As I said, this method is more difficult to get right and can be problematical if one has little or no experience with it. Once the stock is drilled for the pillars, there is no going back (unless filling mis-drilled holes with epoxy or plugs is acceptable to you). Conventional bedding is easier and takes advantage of the inlet areas already existing. As these inlet areas are designed to spread the recoil forces throughout the structure, rather than only through narrow localized portions (as with pillar bedding), conventional bedding tends to put less localized stress on a stock. So, there is a lower chance of inducing cracks, etc.
Often, if the action has a stout, relatively large recoil lug already and if the fit of the action to the stock is good (already), glass bedding can often be limited to the recoil lug pocket (on modern actions) - with acceptable results. (This does not apply to older style actions, such as Mausers, which require more extensive bedding.)
As I said, either type of bedding will produce good results, if done correctly. Oh and I would tend to agree with 4runnerman in that, if the rifle is shooting really well now, it may not need bedding. Most rifles can benefit from some work in this area, but, as I alluded, it is possible to get good results with an abbreviated bedding job, depending on the type of action and the (existing) fit in the stock. It is always best to start small and work up - and this is true of bedding projects as well.
I have seen many gunsmiths recommend pillar-bedding along with bedding the recoil lug area. I have no experience in this matter but it seems you're contradicting that notion. From what I hear the biggest benefit to pillars is consistent clamping force from the action screws. Traditional bedding doesn't help with that right? I may attempt bedding one of my rifles in the future and I had it in my head that I would use pillars and epoxy bed the recoil lug area, as well.
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I do both for customers. If I pillar bed, I always glass the recoil shield and the rear tang as well. Might as well, you are epoxying the pillars in.It IS possible to both pillar bed and glass-bed a stock at the same time. However, why would you want to do so ? No reason to do this - so, it's generally considered a "one or the other" proposition.
Actually, it is a big issue. 100 years ago people realized it. Wood compression is why Mausers came from the factory with a ferrule (steel pillar) in the tang area, because wood tends to compress when screws are tightened, and some wood compresses more than other wood. Pillar bedding takes that variable out of the equation. A well-done glass-bedding job does little to protect against wood compression from overtightening screws.Done correctly, both will produce equal results. Pillar bedding does help somewhat to prevent stock compression over time. This is not a really big issue in most cases, however.
I definitely agree.As I said, this method is more difficult to get right and can be problematical if one has little or no experience with it.
Pillar bedding does not localize stresses, it simply keeps the stock from compressing if done correctly.these inlet areas are designed to spread the recoil forces throughout the structure, rather than only through narrow localized portions (as with pillar bedding), conventional bedding tends to put less localized stress on a stock. So, there is a lower chance of inducing cracks, etc.
One of the most often overlooked rules in the gun world. If it ain't broke, don't fix it.If your rifle is shooting good right now,don't mess with it.
WPS,
I'll respectfully disagree...
Every rifle we own is receiver and pillar bedded.
Done properly, without inducing stress into the receiver during the process, I have never known it to be detrimental to accuracy.
However, done improperly, can certainly screw things up...
Every high end stock I am aware of- has pillars or integral aluminum bedding blocks that serve the purpose.
I'll respectfully disagree...
Every rifle we own is receiver and pillar bedded.
Done properly, without inducing stress into the receiver during the process, I have never known it to be detrimental to accuracy.
However, done improperly, can certainly screw things up...
Every high end stock I am aware of- has pillars or integral aluminum bedding blocks that serve the purpose.
madcratebuilder
New member
It IS possible to both pillar bed and glass-bed a stock at the same time. However, why would you want to do so ? No reason to do this - so, it's generally considered a "one or the other" proposition.
I do both for customers. If I pillar bed, I always glass the recoil shield and the rear tang as well. Might as well, you are epoxying the pillars in.
Done correctly, both will produce equal results. Pillar bedding does help somewhat to prevent stock compression over time. This is not a really big issue in most cases, however.
Actually, it is a big issue. 100 years ago people realized it. Wood compression is why Mausers came from the factory with a ferrule (steel pillar) in the tang area, because wood tends to compress when screws are tightened, and some wood compresses more than other wood. Pillar bedding takes that variable out of the equation. A well-done glass-bedding job does little to protect against wood compression from overtightening screws.
+1000
Many military bolt rifles from the past century have the steel ferrules that act as a pillar to eliminate wood compression.
4runnerman
New member
Every high end stock I am aware of- has pillars or integral aluminum bedding blocks that serve the purpose
Plus 1 on that. Every rifle i have bought in the last 8 years has been pillar bedded right from the factory
Plus 1 on that. Every rifle i have bought in the last 8 years has been pillar bedded right from the factory