Too hot for bolt actions? I dont understand how any ammo could be loaded too hot for a bolt action, but be safe to shoot in a semi or fully automatic gun. I have heard before about some ammo being too hot for certain autos, because it would cause them to cycle too hard and risk breaking parts or at least premature wear. And automatics may have less chamber support, and apply a lot more stress to the brass when feeding.divernhunter said:if it is 50bmg you should not use it in anything other than a M2 full-auto. It is loaded too hot for bolt actions .
Well, I have seen specs for some US military ammo, like .30 M2 Ball, or M80 ball, and the specs listed did not mention that the spec was for machine guns only, or bolt action or semi auto rifles only. Neither is there more than one spec (in use at the same time) for ball ammo in each caliber.divernhunter said:I I have some 303brit that is delinked machine gun ammo and it is very hot in my bolt guns. To be honest with you I am not sure about the whys etc.
Having the brass expand more when fired from a full auto doesnt indicate a higher pressure;I do know that full-auto brass is expanded much more toward the base than semi or bolt fired brass. I had 6000+rounds of 5.56 full auto brass and some of it could not be resizeddue to that.The same thing has happened with some 50bmg I have.
I do know that full-auto brass is expanded much more toward the base than semi or bolt fired brass
That makes sense; I imagine the expanded cases are due to pressure remaining in the chamber when the cartridge begins to be extracted in the full auto. The logical conclusion to this is that the brass gets less support, and therefore is subject to greater stress in a semi or full auto than in a bolt action. In which case, the bolt action would be able to handle higher pressures than the auto, because after a certain point the cases would fail in the auto due to the lack of support before the end of the pressure cycle. Just like those Glock KB!s that are discussed on The Gun Zone forum all the time. So are you cant be basing your theory that MG ammo is loaded hotter than other ammo on the fact that the cases are stretched more, since you acknowledge that this is due to the way the MG works, not the properties of the ammo.The bolt guns confine all the energy(gas expansion) to the chamber and the machinegun does not.
Ahh, now that sounds like potential evidence. What other .303 ammo are you comparing the delinked machine gun ammo to? Did you chrono the delinked machine gun ammo and compare it to the other ammo? Of course any military ammo would be different from civilian ammo; I imagine if you are comparing the surplus stuff to new production civilian ammo then the new stuff is loaded real light because the manufacturers dont want to risk blowing up the almost hundred year old guns that it will probably be fired in, whereas the surplus ammo was designed to be full power and be fired from guns that were new, or at least had been inspected periodically by an armorer.I have some 303brit that is delinked machine gun ammo and it is very hot in my bolt guns.
Did yall discuss this over there? Do you have a link?For more info on the 50 stuff go to the biggerhammer board. They can inform you with the details better than I can.
I've got several US military manuals on MGs and their ammunition and find no documentation for that in US practice. Where is your documentation? The Brits, maybe. Due to so design features of some of their GPMGs.Ammo loaded for machine-guns is hotter than other ammo.
This has a lot more to do with the generous chamber specifications for machine guns and nothing to do with pressure. Chambers in military arms are generally more generous than those of sporting arms so they can function despite dust, mud, rain, high temperatures and other inclement conditions. The chambers of sustained fire weapons tend to be even more generous since accuracy-within generous limits- is actually not as important as functional reliability and no one cares about the condition of the brass..I do know that full-auto brass is expanded much more toward the base than semi or bolt fired brass. I had 6000+rounds of 5.56 full auto brass and some of it could not be resizeddue to that.The same thing has happened with some 50bmg I have.