Forward thinking
Anyone following the complexities of the ongoing move away from lead shot and introduction of ecofriendly wads will have noticed the widely held concerns that steel shot might not provide all the performance we seek. There is a seemingly common misconception that I feel may be worth addressing and that is the part momentum plays in the performance of cartridges we can buy in the UK.
In discussion groups and on shooting forums it is quite common to see pressure being mentioned as the limiting factor regarding what cartridge makers can load for legal sale in the UK.
This is often linked to the higher performance cartridges one can read about in the USA. The question is sometimes raised as to “when is the CIP (the body responsible for setting the levels to which guns here are proof tested and the cartridges must remain within) going to raise the pressure limits to match the American SAAMI rules”.
Ironically, the pressure limits that guns must withstand and cartridges comply with are already higher under CIP high-performance steel than the SAAMI limits. This may confuse some but that’s because there has long been a misunderstanding about the correlation between pressure and velocity among many who shoot.
Higher velocities do not of themselves
