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Bedding under the shank of a barrel?

Phil

Gold $$ Contributor
I have a TINY action with a #8 Pac Nor barrel on it.................Long story.

My question is about extending the bedding under the shank portion of the barrel to add surface area to the action.

The shank of the barrel is 1.2" and runs 4" forward of the action face / recoil lug.

Should i bed this area and free float the rest of the barrel, or should i free float the whole barrel????

Phil.
 
I BELIEVE tenon length to be 1.062, but i`d have to verify this to be 100% accurate.

Barrel length 26.25" in front of the action.
 
My long range gun, built by Al Warner, has a portion of the barrel, directly in front of the action, bedded.
 
IMHO, full free float. As the chamber heats up, the shank OD expands. It may be a miniscule amount, but it still is an added stress on the action screws that changes with barrel temp.(i.e. it will want to lift up from the shank/ bedding interface)
 
LHSmith said:
IMHO, full free float. As the chamber heats up, the shank OD expands. It may be a miniscule amount, but it still is an added stress on the action screws that changes with barrel temp.(i.e. it will want to lift up from the shank/ bedding interface)
Perhaps, you might consider teaching Al Warner the proper way to bed a rifle LH ::) BTW: The barrel will shrink with heat, not expand. We heat turbine shafts, to place the bearings over the shaft. Once the bearing is in place, the shaft cools, and expands to it's original diameter. Same thing happens with pipe that isn't straight. You heat it to cause it to shrink, then cool it to to allow it to move in the direction you want it to go. Once cool, it goes back to it's original size. Same thing with steel rivets. To place a 1" rivet in a 1" hole, the rivet is heated, which causes it to contract, allowing it to fit into the hole. Once it has cooled, it then expands to it's original diameter, giving it a pressed fit. Remember how king pins were removed? You heated them with a torch, they would shrink from the heat, allowing you to knock them out ;)
 
I've seen it plenty of times where the barrel shank is bedded. I'd give it a try and see how it shoots. Worse case it shoots poorly, its easy to take out. Is it right or wrong? This can be hashed out all day long, lol. If you bed and it shoots, is it wrong?
 
I'm with the last 2 guys, I hang a lot of heavy barrels off of 700 actions, and would never bed under a barrel for any reason...
 
The only reason i`m asking is that this particular action is .500" shorter than a Model 7 action.

I have a Cooper that is bedded, approx. 1.0" in front of the action, and it shoots pretty darn good.

This Cooper is the only gun that i have like this, the rest are fully free floated.

This beast of a barrel was initially for a different action, but plans changed, so here i am....lol...

Thanks for all the input and opinions so far.......

Phil.
 
Sorry JRS ;)

Your information is exactly 100% backwards. My job day in and day out is to install tungsten carbide and diamond cutting inserts into gas/ oil drill bits. To do this, I heat the bits via induction heating to approximately 550° to achieve a dimension change of .003- .0035" to allow me to install the inserts that are other wise an interference fit. Steel expands with heat. I see a total growth of .28-.35% at the temperatures I work with.

Dan
 
I know it's not the same thing; but replacing the cylinder sleeves in Diesel engines require the sleeves to be super cooled. I have no proof to offer, but I believe that steel will expand when heated.
 
dantiff2 said:
Sorry JRS ;)

Your information is exactly 100% backwards. My job day in and day out is to install tungsten carbide and diamond cutting inserts into gas/ oil drill bits. To do this, I heat the bits via induction heating to approximately 550° to achieve a dimension change of .003- .0035" to allow me to install the inserts that are other wise an interference fit. Steel expands with heat. I see a total growth of .28-.35% at the temperatures I work with.

Dan
Well Dan, I worked as an ironworker both in the field, and in the nuclear industry for many, many years.
Steel contracts with heat, and expands as it cools. Watch a long span steel bridge as it is being erected. When both halves are brought together to make the final connection, during the day, there is a gap of 18"-20"+. After the steel has cooled overnight, and has EXPANDED after cooling, the connection is made the following morning. Watch the slotted base plates during the day and night. Which way does the base plate move during the heat of the day? When we remove the reactor vessel heads, we can't do so until the reactor has cooled to the point that it has expand to the original diameter. Heat shrinks… cold expands. What does "heat shrink" tubing do? It shrinks, with heat!
 
I feel strongly both ways? Isn't the barrel screwed into the action? and aren't they both made of steel? so don't they both get hot at the same time and both swell? so shouldn't that become a mute point? However I would free float the entire barrel as to not affect harmonics. :o
 
mikegaiz said:
I feel strongly both ways? Isn't the barrel screwed into the action? and aren't they both made of steel? so don't they both get hot at the same time and both swell? so shouldn't that become a mute point? However I would free float the entire barrel as to not affect harmonics. :o
First the thread interface, will cut back on the heat transfer due to actual surface area contact, and 2nd, stainless steel is not a great thermal conductor, causing a wide temperature gradient along it's length.
 
JRS said:
Well Dan, I worked as an ironworker both in the field, and in the nuclear industry for many, many years.
Steel contracts with heat, and expands as it cools.
Well, Rich, I once was an application engineer in cryogenics. Simply put molecules get excited and expand when heated, when cooled they contract.
 
I never bed under the shank of the barrel. The USMC armorers always bed the first 1.5" of the barrel shank. Does it make a difference? I say no.
 

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