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Banned
The .40's SAAMI spec maximum pressure is 35,000 PSI. It drives a 180 grain bullet around 1000 fps.
The 10mm maxes out at 37,500 psi. But it runs that same bullet at 1300, for much more power than the .40. 400 foot pounds vs close to 700.
How does 10mm manage that, with such a small increase in pressure?
Last edited by Uni-Vibe; 01-19-21 at 23:52.
Senior Member
Larger case capacity allows relatively slower and more powder to be used. The identical situation exists with the 30-06 and 308 Winchester (for example).
Andy
Last edited by AndyLate; 01-20-21 at 08:18.
Senior Member
Same with 38 and 357. 44spl and 44mag
38spl has a case length of 29.3mm (9x29R) while the 357 is 33mm (9x33)
44spl (10.9x29R) and the 44mag (10.9x33R)
40sw had a case length of 21.6mm (10x22) while the 10 is 25.2mm (10x25)
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Last edited by Arik; 01-20-21 at 08:58.
Senior Member
Thats not really a valid comparison - the magnums have both increased capacity and a higher allowed pressure.Originally Posted by Arik
38 Super vs 9mm is similar to 10mm vs .40. The Super has more case capacity, lower allowed pressure, and produces about 100 fps higher velocity than the 9x19.
In their defense, smaller cases are more efficient. A 10mm uses more powder to produce the same velocity as the 40 S&W.
Andy
Senior Member
If you know automobile engines you can compare it somewhat to cubic inches / litres and compression.
(I mean mechanical compression from combustion chamber size, not turbos and such)
Manufacturer
Total energy is about more than just peak pressure.
Total energy is related to pressure over time, or the total area under the pressure-time curve.
Simply put, more powder provides more.energy.
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There is no substitute for displacement.
"Freedom is never more than one generation away from extinction. It has to be fought for and defended by each generation."
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Even in the car world, technology is making that statement a thing of the past..
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No it’s not. Apply the technology to a large displacement engine and you get the same gains in horsepower and torque per unit of swept displacement.
Just because automakers elect not to offer something like a DI twin turbo 7.0L V8 with 4 valve heads with variable cam timing and valve lift, doesn’t mean that such an engine wouldn’t match the HP/L of a smaller engine.
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^ Agreed. Technology doesn't change physics. It attains greater efficiency.
As far as chamber pressure like Clint mentioned total area under the pressure curve is key.
I.E. If you take "traction" out of the equation (because this is pretty constant in a barrel) a car will accelerate a whole lot more if you can mash the throttle vs slowly roll on to it. The "chamber pressure" would be exactly the same but performance totally different.
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