Remington glass bed ?

[Waltech Jim]

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ok i just pulled the barrel out of the stock it come out exceptionally well no pin holes no excessive squese out of the bedding compund. it was about a 15 minute clean up with and exacto knife and sharp wood chisel . i used tge score high bedding compund it says it cured in 24 hours

one question how long should i let it sit before i shoot it its a 243 win. with a heavy barrel

thanks jim

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Hi Jim,

Sorry if I highjacked your thread.

It sounds like you got this bedding thing down pretty well. I have not used the bedding compound that you used but IIRC Acraglas is supposed to be given 24 hours to fully cure also. Well, its been way more than 24 hours since you posted the question but I will give you my thoughts anyway.

My gut reaction is to say shoot it, but................if you can wait the required time it might be the prudent thing to do.

I know Acraglas takes some time to get to its final hardness. And I have shot a couple within 24 hours of bedding with no problems at all, but they were small calibers and large barrels.

Jim

[Waltech Jim]

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The problem with using water to achieve thermal equilibrium - evaporation has a significant impact on temp (drop). A far better approach is to bake the object in the oven.

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If I would have used my wife's oven, the lug would have come out at about 400 F and would have been all black and crusty on the bottom. I know because everything she takes out of the oven is that way.

I used a beaker with water and a thermometer sitting on a hot plate. In this way I could regulate the temperature of the water quite well. Right or wrong I used 185 F instead of 180 F to allow for cooling due to evaporation.

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What's missing now is the length of the lug . The coefficient of linear expansion is well know. With the length of the lug we can see how well your measurements fit with established theory.

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The lug has a big hole in it. I don't know how to accomodate a hole when figuring out linear expansion. FWIW I was right on at 150 F and a little (.0002) over at 180 F if you figure about an inch of steel.

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What's also missing is the temp of the lug after heating the pipe/action - and how you measured temp.

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I was trying to duplicate shooting conditions where I know the temperature of the barrel and action, but have no idea what the temperature of the lug is because I can't get at it. It is buried in bedding compound in a stock.

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Good report.

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Thank you.

Jim

[Hired Gun]

So was the measurement taken across the lower solid portion or across the top to bottom of the whole thing? I would believe the bottom solid section is most important. I am curious as both Weatherby's and Ruger's must be bedded solid under the lug. For the life of me I don't see how the lug or action could ever get hot enough in 3-5 shots to change a point of impact. I would believe the barrel would warp slightly long before the actions is goint to get jacked out of the stock to affect impact. Second, if the scope is mounted to said action, it's relationship to the point of impact would not change if the action were to lift .0002". I am thinking this is getting blown way out of proportion for a long range gun.

[Waltech Jim]

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So was the measurement taken across the lower solid portion or across the top to bottom of the whole thing?

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The measurement was taken from the top (of the circle of steel) to the bottom of the recoil lug. I was trying to find out if the lug would expand and push up on the action.


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I would believe the bottom solid section is most important.

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That is my opinion also.


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For the life of me I don't see how the lug or action could ever get hot enough in 3-5 shots to change a point of impact.

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In the rifles I have, 3-5 shots is not going to change the temperature of the action and lug to the point of changing point of impact.


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Second, if the scope is mounted to said action, it's relationship to the point of impact would not change if the action were to lift .0002".

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The .0002 I think you are speaking of is the difference between my measurement of the lug at 180 F and the linear expansion of steel (using J E Customs: 5/8" per ft./100 F) when heated. IOW my figures indicate the lug expanded .0002 more than it should have at 180 F. The lug, measured from the top of the ring to the bottom of the lug expanded .0008 at 180 F and .0003 at 150 F. This is with the lug removed from the action.


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I am thinking this is getting blown way out of proportion for a long range gun.

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If we are talking a few shots, and only addressing heating of the action and lug, I would have to agree. However, the lug did expand so it can be argued that it could affect bedding/accuracy in some situation that I haven't thought of.

Jim

[Hired Gun]

I figured the .0002" would be the growth of the botton piece of the lug in the most extreme of heat situations. I believe that if the lug were to grow that hot and expand that much the stock would also expand with it. That would expand the recess and the support points. This would negate any lift from the lug.

I say bed that lug tight. Let the barrel sag down and be supported by it as well as the bedded action. If you want to bed so that only the rear of it touches I believe that this allows the action to bounce slightly forward and aft after each shot and will not be as consistant as the fully bedded lug.

On a Remington I don't see it would hurt anything to float just the very bottom of the lug. On actions that have the lug built in, I think it is imperative that the lug be fully supported/bedded.

[zingdingo]

Out of curiosity, why should the lug be bedded differently depending on its attachment method? (screwed on vs. integral)

[Hired Gun]

On the Ruger and Weatherby actions the forward action screw actually goes right into the bottom of the recoil lug. If left unsupported, it pull down on the front of the action and puts a downward bending tension on the front of the action.