bedding chamber area in front of recoil lug

C

chino69

New member
I know this subject has been beat up many times so please forgive me asking again. I am basically looking for a concensus from some of those who have experience with both methods and results. The topic is whether to bed the chamber area in front of the recoil lug to give added support to heavier barrels. I have a Bartlein barrel 1.250" X 5.000 Straight tapering to .940 approx. 26" long. The action is pillar bedded in an aluminum chassis stock. I've heard it done both ways but would appreciate hearing from those who can provide some data, i.e. (forces acting on unsupported beam) to help in my understanding.
 
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what cartridge, what is the function of the rifle ?
glued in action, and bbl changed in place, then no.
hunting rifle why not
 
bed chamber area

retired said:
what cartridge, what is the function of the rifle ?
glued in action, and bbl changed in place, then no.
hunting rifle why not
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Sorry for lack of info.. Switch barrel rifle for varmint hunting, target shooting, informal matches. Borden single shot Alpine action with pinned recoil lug. Action pillar bedded. Barrels run from .243 AI, .308 to 6mm BR.
 
bedding chamber area

jackie schmidt said:
Exactly.

Bedding the chamber area used to be popular with old military actions, which are quite flimsy with all of the cut always.
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Jackie,
It is a Borden single shot Alpine action with pinned recoil lug. Switch barrel rifle with barrels chambered in .243 AI, .308 & 6mm BR. Action is pillar bedded into stock, not a glue in. Used for varmint, target and informal matches. My question is there enough weight hanging unsupported to be a concern or is that configuration enough not to be a concern? I have seen it done by some gunsmiths who build accurate rifles.
 
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bedding chamber area

alinwa said:
maybe because the chamber area swells when subjected to 50,000psi?
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Al,
Interesting; the chamber swelling that is. How much are we talking about? I assume because of that the answer is not to bed the chamber area. My real question relates to how much weight is hanging out there unsupported and whether it is a concern or not. We're talking about a 7 lb. barrel. My only reason for asking is I have seen it done by some gunsmiths who build accurate rifles.
 
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chino69 said:
Al,
Interesting; the chamber swelling that is. How much are we talking about? I assume because of that the answer is not to bed the chamber area. My real question relates to how much weight is hanging out there unsupported and whether it is a concern or not. We're talking about a 7 lb. barrel. My only reason for asking is I have seen it done by some gunsmiths who build accurate rifles.
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OK..... As with things like the size of our galaxy, or the number of dollar bills in our national debt, I like to "put things into perspective I can grasp"

So we've got a threaded barrel tenon over an inch in diameter threaded into an action at near an inch three fifty, seems we're talking about "hundreds of pounds" here, maybe thousands..... maybe TONS.......but we don't have PERSPECTIVE yet.......

So.....


We take the barreled action out of the stock and we hold it, like a pool cue, or like a sword. And we shake it around....swish, swish......


Seriously??? We're worried about WEIGHT on the joint? Bending or lifting the action center?

ennyways,

That's my perspective.....
 
I just got back up from the shop, bedding some guns, lapping and mounting and gluing scopes..... and I tried a little test. (I got guilty thinking my swishing the sword around analogy might seem flippant)

Big 30" live varmint barrel on a Rem 700. 1.250 shank for 3" then tapered to just over an inch at the muzzle. Dunno if it's 7lb but it's heavy. Wide open freefloat around the barrel and for once, some play in the recoil bedding...... this is one I did back when I taped the front and sides of the lugs.

I installed the front action screw leaving the back or tang screw out.

Now, when the front screw is loosened and tightened the barrel falls down into the forend channel.....the rear tang lifts. And what I'm saying is ON THE REM700 it doesn't take much pressure to suck the screw down, in fact with an inletting screw in place you can pull it down with your fingers.

One of the things that became apparent to me while fiddling with this is, this is a good design! Some actions, like the Weatherby's have the front screw actually in the lug, ALL of the bending forces are absorbed by the action rails and body.

So, I stand by my contention that there's no reason to bed the barrel on a Rem700 or modern custom action. Your Borden is wikkid fine....

And I realized another thing. I hadn't really thought about this for 20+yrs, back when I was asking the same question! And guys like Jim Borden were telling me "don't bed the barrel"

Nowadays I'm more worried about other forces, resistance to uplift, feedback and stock flex thru the magazine area, I hadn't taken the time to think this thru for quite some time.
 
bedding chamber area

alinwa said:
I just got back up from the shop, bedding some guns, lapping and mounting and gluing scopes..... and I tried a little test. (I got guilty thinking my swishing the sword around analogy might seem flippant)

Big 30" live varmint barrel on a Rem 700. 1.250 shank for 3" then tapered to just over an inch at the muzzle. Dunno if it's 7lb but it's heavy. Wide open freefloat around the barrel and for once, some play in the recoil bedding...... this is one I did back when I taped the front and sides of the lugs.

I installed the front action screw leaving the back or tang screw out.

Now, when the front screw is loosened and tightened the barrel falls down into the forend channel.....the rear tang lifts. And what I'm saying is ON THE REM700 it doesn't take much pressure to suck the screw down, in fact with an inletting screw in place you can pull it down with your fingers.

One of the things that became apparent to me while fiddling with this is, this is a good design! Some actions, like the Weatherby's have the front screw actually in the lug, ALL of the bending forces are absorbed by the action rails and body.

So, I stand by my contention that there's no reason to bed the barrel on a Rem700 or modern custom action. Your Borden is wikkid fine....

And I realized another thing. I hadn't really thought about this for 20+yrs, back when I was asking the same question! And guys like Jim Borden were telling me "don't bed the barrel"

Nowadays I'm more worried about other forces, resistance to uplift, feedback and stock flex thru the magazine area, I hadn't taken the time to think this thru for quite some time.
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Al,
I appreciate you taking the time to perform this little test and to satisfy the answer to my question. As far as your 1st analogy about the sword swishing around I liken it to the use of spices when making food dishes; it sets it apart from a bland response. Actually I follow your posts as I enjoy your wit and experience. I can now sleep a bit easier at night and only worry myself about the current state of humanity. Thanks again.

p.s.: You no longer tape the sides and front of the recoil lug when bedding? What is the reason for that?
 
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Bedding in front of lug . Leverage Effect?

Bedding in front of the recoil lug may act as a wedge? The barrels weight becomes the lever. This may increase force on the action?

How the barrel is bedded may make a difference?
1.Barrel, If bedded while free hanging, under its own weight, there should not be any leverage applied? And no benifit from the bedding?

2. Applying bedding with 9 lbs up pressure on the muzzle of the barrel , when the up pressure is withdrawn, would seem to apply a leverage effect on the action? Or more stress on tne action? https://www.omnicalculator.com/physics/mechanical-advantage#simple

The above is very interesting to look at online. Now if someone a lot smarter then i , would comment, might be more interesting.

My first rebarrel on a M70 by paul jaeger gunsmith jenkintown pa in the 70s, had about 2" of bedding in front of the lug. Had some problems with the work and accuracy. I ended up removing the bedding in front of the lug myself.

With the bedding remove, the heavy barrel drooped a lot. Requiring a lot of wood to be removed from the forearm.

I agree , no bedding in front of the lug.. Metal does expand on firing, even more so with some modern cartridges running at 65,000 PSI.
 
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chino69 said:
Jackie,
It is a Borden single shot Alpine action with pinned recoil lug. Switch barrel rifle with barrels chambered in .243 AI, .308 & 6mm BR. Action is pillar bedded into stock, not a glue in. Used for varmint, target and informal matches. My question is there enough weight hanging unsupported to be a concern or is that configuration enough not to be a concern? I have seen it done by some gunsmiths who build accurate rifles.
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One reason you would NEVER bed the chamber area of a switch barrel gun is the OO of the barrel will not be exactly like the one before, either in exact diameter or how true it runs with the thread. A good bedding job is an exact mold of the action. If the change barrel ran out any at all, it would no longer be a “perfect” bedding job.

Your Borden Alpine is certainly capable of supporting what amounts to a Heavy Varmint Profile.
 
bedding chamber area

jackie schmidt said:
One reason you would NEVER bed the chamber area of a switch barrel gun is the OO of the barrel will not be exactly like the one before, either in exact diameter or how true it runs with the thread. A good bedding job is an exact mold of the action. If the change barrel ran out any at all, it would no longer be a “perfect” bedding job.

Your Borden Alpine is certainly capable of supporting what amounts to a Heavy Varmint Profile.
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Jackie,
Thanks for the response. I knew that the OD issue was one reason but I wanted to hear the recommendation(s) from several seasoned shooters and the informed concensus is not to bed. Understand I come from an engineering background which can be a blessing and a curse, depending on the circumstances. When I look at a barrel supported on one end my engineering brain sees a cantilevered beam with deflection, which is why I reach out to those with some real world common sense experience. It happens all the time. Thanks again.
 
chino69 said:
p.s.: You no longer tape the sides and front of the recoil lug when bedding? What is the reason for that?
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Ohhh man, a TON of reasons all based on my re-assessment of what bedding actually DOES in the system and on analysis of the forces acting during recoil.

To see it from my side, start with my belief that the action is kinda' like just as you pull the trigger Hank Aaron connects with your ogive trying to send the whole apparatus over the left field fence....... while the bullet is still in the barrel......

Probably safer to stick with the old "bed for compression" and "recoil straight back" so "riding the bags is important" models LOL!!!
 
bedding chamber area

alinwa said:
Ohhh man, a TON of reasons all based on my re-assessment of what bedding actually DOES in the system and on analysis of the forces acting during recoil.

To see it from my side, start with my belief that the action is kinda' like just as you pull the trigger Hank Aaron connects with your ogive trying to send the whole apparatus over the left field fence....... while the bullet is still in the barrel......

Probably safer to stick with the old "bed for compression" and "recoil straight back" so "riding the bags is important" models LOL!!!
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Al,
I was just getting back to getting a good night's sleep over the answers to my bedding under the chamber question and now you introduce this. Time for the Maalox! O.K., I see your point. From hence forth, I will keep that in mind but for that which is already bedded should this be a concern? Or should I just leave well enough alone? Christ, here goes another restless night.
 
chino69 said:
Al,
I was just getting back to getting a good night's sleep over the answers to my bedding under the chamber question and now you introduce this. Time for the Maalox! O.K., I see your point. From hence forth, I will keep that in mind but for that which is already bedded should this be a concern? Or should I just leave well enough alone? Christ, here goes another restless night.
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Glue-ins work because they make the action and stock into basically one unit...... gluing makes them act together, consistently.

Gluing and screwing is arguably even better.

But making a screwed gun shoot like a glued gun.... acchhh, for this schlemiel 'ZAT is hard't..... but doable.
 
bedding chamber area

alinwa said:
Glue-ins work because they make the action and stock into basically one unit...... gluing makes them act together, consistently.

Gluing and screwing is arguably even better.

But making a screwed gun shoot like a glued gun.... acchhh, for this schlemiel 'ZAT is hard't..... but doable.
Click to expand...

Al,
That I can understand and ensures the consistency required in competitive shooting. I just don't think it warrants me going through that process for what I do; varmint hunting, groundhog matches and shooting in general. The action is properly pillar bedded and it would requiring going through a whole new process. I have Jewell triggers on all four of my switch barrel rifles and hose them down bout once a year with lighter fluid and action out of stock. Thanks for the reply, knowledge and insight.
 
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I wouldn't worry a lot

chino69 said:
Al,
I appreciate you taking the time to perform this little test and to satisfy the answer to my question. As far as your 1st analogy about the sword swishing around I liken it to the use of spices when making food dishes; it sets it apart from a bland response. Actually I follow your posts as I enjoy your wit and experience. I can now sleep a bit easier at night and only worry myself about the current state of humanity. Thanks again.

p.s.: You no longer tape the sides and front of the recoil lug when bedding? What is the reason for that?
Click to expand...

about action flex and scores. If you look at the IBS records, Al Kogoy Jr holds the Hunter record for 100 yds with a 250-24X. I think what this tells one is that it's what happens out ahead of the bolt face that matters and should be thought about. I wouldn't go so far as to worry about any of it.

Pete
 
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