Navigating the world of shotgun cartridges can be confusing, especially when comparing UK and US standards. Shooters in the UK often encounter cartridges labeled with both English and European shot sizes, adding to the complexity. Furthermore, proof laws and speed measurement methods differ, leading to potential misunderstandings about advertised performance. This can result in shooters unknowingly using smaller shot sizes at speeds that may not match expectations.
In the UK, a preference for 1 1/8oz of English #5 shot is common. However, this is actually equivalent to a US #6. The consensus speed in the UK is often cited as 1300fps, but real-world velocities may be closer to 1200fps under typical conditions. This discrepancy means UK shooters might be using shells with smaller shot and potentially lower actual speeds than they anticipate based on advertised figures. The issue extends beyond shot size and speed, impacting the selection of appropriate cartridges for various shooting disciplines.
The antimony content in cheaper pigeon loads also plays a crucial role. Lower antimony levels result in softer lead, which, while ballistically similar in some respects, can lead to deformation at high velocities. Extremely soft lead combined with very high speeds like 1600fps can cause significant shot deformation within the barrel, effectively wasting a portion of the shot charge before it even leaves the gun. For a deeper understanding of shot size comparisons, resources like the Lyman guide offer valuable references to both European and American shot sizes, often recommending a 2% antimony content for standard loads.
Considering these factors, a standard pigeon load in the UK, using a #5 English shot size at a realistic 1200fps, might seem counterintuitive when aiming for optimal performance. It can be more costly to achieve seemingly lesser performance. However, in some scenarios, “less is more.” Many shooters find advantages in using slightly larger shot sizes than typically recommended, often going one size up. This allows for effective performance at slightly reduced velocities.
The rationale behind using a larger shot size at a lower velocity is compelling. Why choose a #6 shot at 1400fps when a #5 shot at 1100fps could potentially deliver superior results? The larger, slower shot can maintain more energy downrange and, when used with certain wad types like full cup wads, often produces improved patterns through various chokes. Anecdotal evidence from conversations with reloaders also suggests inconsistencies in actual shot sizes compared to labeled sizes, highlighting the importance of careful component selection and verification. In essence, understanding the nuances of UK shot sizes compared to US equivalents, alongside velocity considerations and component quality, is crucial for informed cartridge selection and achieving optimal shooting performance.
