Nolo,
At 4000fps out of say a 16" barrel, the propellant has to have been effectively fully combusted in > ~ 1/3000 second. There will be markedly higher pressures due to faster and thermally hotter propellant
(I know in reality this is not exact but for discussions sake)
At these sort of velocities we are starting to move towards explosives and past propellants and the increased velocity leads to additional issues.
Spin rate has to be markedly adjusted else the round will be spinning so fast on exiting the barrel that centrifugal force can cause the round to mechanically "explode" within a few metres of the barrel. You can see examples of this with 40gr .223 rounds in a 1:7 twist barrel.
Higher speed rounds will tend to erode/wear the barrel faster as well as the higher pressures of the propellant causing additional mechanical stress on the gas system.
The bolt and chamber will be subject to markedly higher pressures and will need to be appropriately reinforced and probably re-engineered. There has already been a lot of work undertaken to increase the mechanical strength of the current bolt lugs with faster twist .223's and this will have to be re-asessed.
Just ramping up the velocity and reducing the mass will also mean re-engineering the round mechanics or else we end up with a round that is too unstable to be accurate or too fast and stable to do other than knitting needle punches in the target. Most of the energy will be lost down range as it will either simply be a through and through with some upleasant but survivable temporary cavitation in the wound channel or it will be moving so fast that yaw and tumble will start to occur as or after the round has exited.
It's meeting the sweet spot between Kinetic Energy, Ballistic Co-efficient, round stability and round cross section.
At 4000fps out of say a 16" barrel, the propellant has to have been effectively fully combusted in > ~ 1/3000 second. There will be markedly higher pressures due to faster and thermally hotter propellant
(I know in reality this is not exact but for discussions sake)
At these sort of velocities we are starting to move towards explosives and past propellants and the increased velocity leads to additional issues.
Spin rate has to be markedly adjusted else the round will be spinning so fast on exiting the barrel that centrifugal force can cause the round to mechanically "explode" within a few metres of the barrel. You can see examples of this with 40gr .223 rounds in a 1:7 twist barrel.
Higher speed rounds will tend to erode/wear the barrel faster as well as the higher pressures of the propellant causing additional mechanical stress on the gas system.
The bolt and chamber will be subject to markedly higher pressures and will need to be appropriately reinforced and probably re-engineered. There has already been a lot of work undertaken to increase the mechanical strength of the current bolt lugs with faster twist .223's and this will have to be re-asessed.
Just ramping up the velocity and reducing the mass will also mean re-engineering the round mechanics or else we end up with a round that is too unstable to be accurate or too fast and stable to do other than knitting needle punches in the target. Most of the energy will be lost down range as it will either simply be a through and through with some upleasant but survivable temporary cavitation in the wound channel or it will be moving so fast that yaw and tumble will start to occur as or after the round has exited.
It's meeting the sweet spot between Kinetic Energy, Ballistic Co-efficient, round stability and round cross section.
Seems like the 6.5Grendel/6.8 SPC, Etc. were made obsolete in 1895....
