doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com The effects of higher pressures

I was comparing reloading recipes recently, and was surprised at the extent to which using different wads can affect load pressures. Which led to this question: Assuming you are shooting a gun with modern steel barrels, and using loads within the gun's proof, is there any benefit to shooting lower pressure loads? If a gun is proved to 13,000 psi, does shooting 8,000 psi loads instead 10,000 psi loads (assuming the fps and shot charge are the same) extend the time before a gun shoots loose?

Put another way, is it worth spending extra money on higher quality wads to reduce the pressure in my reloads 1500-2000 psi?

Thanks in advance, Doverham

Given two loads with equal velocity, but one which is 8000 psi vs the other at 13,000 psi, it would stand to reason that recoil should be equal, but wear on bolting and jointing surfaces would be accelerated with the higher pressure load.

Pretty much any mechanical device wears out or breaks quicker as you run it near or beyond its' design limits. Indy and NASCAR cars go like hell, but they sure don't go 200,000+ miles between engine rebuilds.

There are so many variables that must be answered in order to answer the original question intelligently, I'm not going to really try. If the peak pressure pulse is very brief, it may actually cause less wear and tear. Note, I said may.

and, the more you shoot high pressure loads the sooner the wood will crack.

Say what ED ????????

bill

Virginian - I would be curious to hear what are some of the more important variables needed to answer the question.

Thanks, Doverham

bill: the theory is that the weakest part of a gun is the wood. so, the more you stress the wood the sooner it will crack. high pressure loads generate lots of recoil. recoil stresses wood...

If the weight and velocity of the shot of a high pressure load and a low pressure load are the same then the recoil is the same.

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100% correct, pressure does not enter in the formula for calculating recoil. Max chamber pressure is but one component of the total barrel pressure. Pressure is applied from ignition, before the load starts to move, until the load exits the barrel. It is of course not a constant, but a curve. If you push the same load (include everything that goes out the barrel, shot wads & powder) to the same velocity then you have done the same amount of work. While the peak/max chamber pressure may vary widely depending upon the burning rate of the powder, the total pressure under the curve for the length of the barrel will for all practical purposes be the same. Thus recoil & the force against both the wood & the shooter will be equal.
A quick perusal of a loading manual shows I can easily find a 1oz load with 1200 FPS velocity @ a max pressure of 10,600 PSI. I can just as easily find a 1�oz load with 1275 FPS velocity @ max pressure of 8,200 PSI. Fire them both out of a 6-6� lb 12ga & then tell me which pounds both you & the wood the most.