This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.
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he also posted this...i dunno what the round on the far right is
I remember someone here claimed more info, basically the case was loaded with Rocket fuel and ran at 80-100k psi. Some of these proposals we are seeing... I wanted it scaled to 6mm or .257, but I am odd.
I would really like to know how thoroughly that round was tested. Was it fired only in test barrels, or were any machine guns and assault rifles converted?
I'm very skeptical that such a long, thin, un-tapered case would chamber and extract reliably in automatic weapons, especially after propellant residue has accumulated in the chamber.
I suspect it was tested just enough to get velocity readings... a slight taper should not have been impossible. perhaps with the new case designs we are seeing it could be revisited, though the comment I referred to earlier indicated the Propellant would have been hugely expensive.
For all the new case designs, I still think the one DTIC talked about years ago was very promising. It was an Aluminum head, thin stainless steel body.
It saved so much weight in the case that it was stated the loaded weight of the round was reduced enough to allow an extra round for IIRC every 5 rounds.
so 20% Cartridge savings.
With some of the high strength aluminum alloys, I wonder what pressures it could have handled, for the topic of this thread.
found some more recent information on the design. \ I forgot how much I liked NDIA
This particular presentation was about a .338 Norma case for the LW MMG concept. it is a little different from the previous one I had seen that was for 7.62x51mm.
now the aluminum head is on the outside, rather than being inside the stainless steel body. am I converting correctly, is 500 Mpa = 72518.9 PSI?
Im more interested in the claim of a 75percent heat reduction....what kind of wizardry were they applying to the propellants to achieve this
What were the particulars of that 75% heat reduction?
They said it was all down to the propellant...didnt talk about it much.
Strikes me as a good method to lower barrel wear with rounds like the 300win mag
Numerically, your MPa to PSI conversion is correct.
But keep in mind that there a several methods of measuring pressures in use (CIP, SAAMI, EPVAT, you name it; not to mention copper crusher versus piezo) which can yield very different results for thes ame cartridge. Any numeric conversion gives you only a ballpark value.