Component Analysis
[TBC]
It was possible to recover some of the wads from the Eley cartridges after firing. They showed deep pellet impressions in the surface of the wad (although none were retained) and significant expansion of the wad outwards to seal the bore with associated scrubbing marks around the outside edge. These features suggest that the wads are relatively soft and pliable. Brittler fibre wads will often suffer damage, crack or disintegrate at the chamber edge or choke which may allow combustion gases to pass the wad and interfere with the shot. We suspect that this is not an issue with the Eley cartridges.
Pattern testing was performed on a particularly hot, late spring afternoon. The primer / brass of the fired cartridges were noticeably hot after firing – something which we hadn’t noticed when performing initial tests on a cold April afternoon. This suggests that the powder is particularly temperature-sensitive. An increase in recoil, heat generated and case expansion suggests higher pressures – not unexpected with a 10-15°C rise in temperature – and probably higher muzzle velocities. (See below for comments regarding muzzle velocity.)
Performance Data
| Date | Range | Choke (Nominal) | 30" Circle Impacts (Total) | Performance (Nominal) |
|---|---|---|---|---|
| 22/04/2017 | 20 Yards | 0.020" (Improved Modified) | 144 (148) | 97% (> Improved Cylinder) |
| 11/06/2017 | 30 Yards | 0.015" (Modified) | 109 (148) | 74% (Improved Cylinder) |
| 11/06/2017 | 30 Yards | 0.015" (Modified) | 115 (148) | 78% (Modified) |
| 22/04/2017 | 30 Yards | 0.020" (Improved Modified) | 106 (148) | 72% (Improved Cylinder) |
| 11/06/2017 | 30 Yards | 0.020" (Improved Modified) | 121 (148) | 82% (Modified) |
| 11/06/2017 | 30 Yards | 0.020" (Improved Modified) | 114 (148) | 77% (Modified) |
| 11/06/2017 | 40 Yards | 0.020" (Improved Modified) | 73 (148) | 49% (Improved Cylinder) |
| 11/06/2017 | 40 Yards | 0.020" (Improved Modified) | 79 (148) | 53% (Improved Cylinder) |
Performance Analysis
Considering the components which comprise the loading, the Eley “Fourlong” cartridge produces, in all respects, extremely impressive performance.
If we specify a minimum standard of 120 pellets in the standard circle, then the “Fourlong” cartridge is usable to a distance of around 28-29 yards on the basis of the data collected so far. Given the light loading of only 7/16oz., this is remarkable: other cartridges with 50% more shot tested by the SmallBoreShotguns team have failed to achieve this kind of usable range. Furthermore, the percentage performances of this cartridge generally exceed at all ranges those any other cartridge thus far tested.
Of possibly greatest significance to this cartridge’s performance over and above the others tested by SmallBoreShotguns is the low muzzle velocity. The cartridge is advertised as having a “V1” velocity of 1066fps on the Eley Hawk website. This suggests that the muzzle velocity is also subsonic, though due to the difficulties inherent in interpolating “V0” from “V1”, it could be marginally either side of the nominal speed of sound of 1116fps.
The question of muzzle velocity is further complicated by the fact that the pattern testing that produced much of the data presented above was performed on a particularly hot day: on the basis of the test gun’s report and noticeably increased recoil from previous testing, the cartridge was clearly projecting the shot column at supersonic velocity. This suggests that the powder used is somewhat temperature-sensitive and that best performance (and quietest report) will be obtained when the ambient temperature is low.
Nevertheless, when compared to commercial offerings in .410 and other gauges, this is a “slow” cartridge and the relatively high pattern percentages it produces fit in with the general trend we have seen in all of the data so far: high muzzle velocity tends to degrade patterns.
Also no doubt of significance in explaining the excellent percentage performance the Eley cartridge produces is the relative shortness of the shot column. In other 2½” loadings containing ½oz. of shot, the pellets will experience more crushing before the crimp gives way. The (apparently) relatively soft wads used in the cartridge probably cushion the acceleration of the column to some degree, also reducing pellet damage and consequently the number of “fliers”.
Furthermore, that wads from the cartridge are recovered deformed but intact (as opposed to disintegrating as they leave the barrel, producing “confetti”) suggests that obturation is good and that combustion gases are not able to pass the wad and reach the shot to interfere with it. This is also a boon to performance and perhaps a surprising one, given that the half-inch “jump” to the end of the chamber and the hard edge from chamber to bore could both conceivably damage the wad as it accelerates up the barrel.
Example Patterns
