Darius137 wrote:Notice that what we believe is not always what is true? I recommend many of you go out there and challenge what you have as beliefs to sound reasoning. You'll find that many of what you used to think are beliefs--even core beliefs--are just opinions you've had long enough to make you think they are based in reality.
The airsoft community at large believes that because we've been using 330 or 350fps as our standard because of some sort of safety reasoning.
That's because it
is inherently safer than a 400FPS standard. Basic physics shows us that two objects of identical mass traveling at different velocities will have different kinetic energies. There is a clear and direct correlation between the amount of kinetic energy an BB possesses and the amount of damage that BB will inflict when it meets its target.
One could argue that the difference in the velocity of a projectile at 330FPS versus the same projectile at 400FPS is not great enough to be considered a safety liability. However, I think a strong argument could be made the other way. Strictly speaking on the basis of anecdotal evidence, people in this community, at large, seem to think that 400FPS is not a limit, but a
goal. There are consistently discussions surrounding getting guns to shoot at their respective limit. This alone is enough to warrant a serious examination of the safety of certain velocities when event promoters exercise their right to promote games that are not in adherence to community guidelines (my own games included).
Let's play with numbers.
Simple math tells us that force F is equal to mass M times acceleration A.
To do this equation we must find acceleration. Acceleration can be defined as the change in velocity V divided by time T.
A= Change in V/T
First we convert FPS into m/s.
400FPS x 0.305 = 122m/s
330FPS x 0.305 = 100m/s
For time we must consider the environment at hand. In my experience with strict CQC environments (within structures) , most engagements happen at 5m or under. So:
5m / 122m/s = 0.041s
5m / 100m/s = 0.05s
Back to acceleration:
122/0.041 = 2975 m/s^2
100/0.05 = 2000 m/s^2
Now to force:
0.0002kg x 2975 m/s^2 = 0.595N
0.0002kg x 2000 m/s^2 = 0.4N
So, in very simplified terms, the difference in impact force of our 0.2g projectile is 1.95N between 330FPS and 400FPS. In other words:
A BB traveling at 400FPS carries 33% more force than the same BB at 330 FPS
I don't know about you, but that seems like a pretty big difference to me. Please keep in mind that my equations do not account for negative acceleration as a result of drag or other forces acting on the BB. However, the effects of those parameters should apply roughly equally to both projectiles.
I'm not going to get in to the amount of force required to break skin, because there are far too many important variables to consider when it comes to kinetic energy impacting an elastic object (skin), especially when the elastic force that skin will exert on the BB will vary widely depending upon the amount of collagen in the skin, the location on the body, etc.
However, with a 33% difference in the impact force involved between BBs at the two different FPS limits, it is a pretty safe statement to say that a 330FPS limit will yield consistently safer gameplay than a 400FPS limit, at least when engagement distances are close enough for the BBs to be traveling near their initial velocity when they impact their target.
Therefore, Dan, I will readily buy that your decision to not establish separate FPS limits for the MOUT scenarios is one made for convenience, but please don't claim that there is not a substantial difference in the safety of using a lower velocity.
