I am curious as to what everyone's opinions are as to what causes the death of the SXS double. Stress calculations would indicate that in fact a properly designed double is as strong or stronger than a Mauser (on paper anyway).

I promise not to be an egomaniac elitist. Just thought this might make an interesting thread and bring forth some good discussion.

One thing I would like everyone to keep in mind is, if the fit is good initially and the stresses are well below the yield point (say 70% of yield strength) then the steel shouldn't be moving (permanently anyway)!

Todd E

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Alf,

Thanks for the information. Believe it or not I agree with it. The principals are all based on solid engineering. How does the flexing wear down the action? Is there any experimentation documented in your sources?

To provide some additional detail on some of the topics covered.

Young's Modulus (aka the modulus of elasticity) for all steels ranges between 29.4E6 psi to 30E6 psi. It is typically designated "E". It is a basic mechanical property of a material.

The basic equation for deflection is defined as: the second integral of the forcing function divided by the product of Young's Modulus (E) and the Area Moment of Interia (I).

Young's Modulus, as Alf's reference material indicates is a function of the material. It is in reality practically constant for all steels. Some of the stainless varieties will make it to 30E6 psi.

The Area Moment of Inertia (I) is a function of the cross section itself.

Therefore, for all practical purposes it will be the cross section, more than the steel used (Young's Modulus), that will determine the stiffness of the action as a whole.

Steel is an elastic material. It will have a spring rate, but should return back to it's original shape/position upon relaxation of the load without any permanent set. This is true as long as you do not load the steel (or any material for that matter) above it's yield strength (elastic limit).

Todd E

In my opinion, outside the warping, or cracking of the action by excessive pressure, which I do not consider to be "WEAR". I think poor care in cleaning, and lubrication are the grimlens that eat away precious steel on mateing surfaces. This wear is the most damageing on the slideing bar/bite surfaces, and henge pin/lumphook surfaces. My .02 cents

If the calculations show that a double is stronger than a bolt, then there is something wrong with the calculations.

Overwhelming evidence from 150 years of double rifles shows them to be far weaker than bolts and not suitable for high pressure modern cartridges.

Amen, 500grains!

500grains,

Before you go off regarding the strengths of various actions you should study more about what you speak. Just to determine if you have done your homework could you please answer the following questions:
1.) Thrust force from a 300 Win Mag loaded to 51500 CUP?

2.) Thrust force from a 470 NE loaded to 38500 CUP?

Mac, I agree 100% with your post.

Todd E