Originally Posted by anphelproject
now my local field is a 400FPS field but they reconize that the guns comming into Canada are shooting hotter then this so they are asking for chrono to be done with .25 thus making most guns shoot around the 400 FPS mark.
That's completely moronic and defeats the purpose of chronying.
As others have explained, it amounts to saying "The speed limit is 100 and you're driving over that limit at 150kph, but we'll just measure your speed in MPH instead so you're still under 100."
Whatever field that is needs to pull their head out of their ass and unfuck themselves.
Originally Posted by slink182
In Canada, the momentum limit was determined by the RCMP, and enforced by the CBSA (more or less). The RCMP's determination is based on the energy requirements to break skin, which is about 1.5 Joules. Therefore, working backwards and solving for velocity, this is where the 400 fps limit comes from (based on a 0.20 g BB). Increasing velocity with a 0.20 round, or increasing BB weight with a 400 fps limit, will result in the energy value increasing above the "skin break" threshold (i.e., greater than 1.5 J).
The original limits, back in the day, came more from trial and error