Could this new fibre cup wad cartridge offer the clay busting performance you’re looking for, asks Richard Atkins
The cartridge world is taking the move to becoming ‘eco-friendly’ very seriously, and new and smaller brands are getting very much involved. Last month we looked at the new Spanish brand, Bio Ammo, and this month we feature a pair of novel clay loads from Jocker: a 24 gram and a 28 gram, both in 7.5 shot size.
The Jocker brand has made a modest name for itself during recent years in UK. The cartridges are imported and distributed by Shooting Star Ltd, who are the long time importer and distributor for the well known RC ammo.
These standout feature in these new Jocker cartridges is the novel fibre cup wad. This wad has been in development for more than two years now. That might sound like a long time for something that looks fairly simple, but my engineering background helps me to understand the trials and tribulations, not to mention serious investment, that it takes to turn an idea into a reality that can be produced by the million.
Understanding the test results
- Velocity is measured at 2.5 metres from the muzzle.
- Pressure is the mean breech figure in Bar (as per CIP).
- SD is Standard Deviation (consistency).
- CD is the Central Density rating. This records the percentage of the total pellets landing in the 30-inch circle that were also within the inner 20-inch circle
- Shot size is derived from actual pellet count per ounce and is listed to the nearest UK size, with < and > symbols where shot is slightly larger or smaller than the nearest size. UK No.7 = 340 pellets/oz; UK No.7.5 = 400 pellets/oz; UK No.8 = 450/oz; UK No. 9 = 580/oz.
- Shot weight is the average actual shot load, measured in grains. 1 grain = 0.065 grams = 0.0023 oz. CV is Crush Value. This is the amount by which the shot is reduced in size when subjected to the standard crush test. A smaller value means harder lead, so a CV figure of 20% is harder than 30%, for pellets of similar size. Smaller shot crushes proportionately more than larger size.
- Choke boring Nominal pattern percentages at 40 yards are: Half Choke 60%; Imp/ Mod (three quarter) choke 65%; Full choke 70%.
Jocker Bio Sport Competition 24g 7.5 shot – specifications
|Shot load||368 grains|
|Pellet (count per oz)||338|
|UK shot (size / CV)||7 / 30%|
|Pellets in 30in dia (Av)||187|
|Pellets in 20-30in||79|
|Recoil (M) (unit= Ns)||9.4|
|Pressure (unit = bar)||530|
Jocker Bio Sport Competition 28g 7.5 Shot
|Shot load||434 grains|
|Pellet (count per oz)||340|
|UK shot (size / CV)||7 / 30%|
|Pellets in 30in dia (Av)||227|
|Pellets in 20-30in||102|
|Recoil (M) (unit= Ns)||10.8|
|Pressure (unit = bar)||595|
The Bio Sport shells are packaged in bright, smart, predominantly blue cartons of 25 with the name printed large in white on the front, and black on the top flap. These cartridges are very easy to identify! The
top flap also has details of calibre, length, metal head height, shot weight and size and wad type.
Both the 24 and 28 gram type are loaded into a strong, transparent, pale mauve plastic case with 12mm metal head. The case is made from conventional polyethylene, as are almost all cartridges today, with most clay shoots collecting fired cases, sometimes for recycling.
These cases are made for Jocker by Spanish company Maxam. Their surface finish is smooth and not longitudinally ribbed as Maxam cases often are. A novel feature is that these cases are not printed in the usual way. They are transparent, save for a mauve tint, allowing you to see the printing on the wad inside.
The loaded cartridges are closed with a well formed, tight, six-point star crimp which has been neatly rolled to create a smooth, regular crimp closure. This ensures easy feeding into the chamber and through semi-automatic guns.
The fired cases are completely clean and remain ‘see-through’; they also retain a strong crimp memory and a very firm case mouth. This denotes high grade cases; any home loaders take note as these should reload rather well!
The primer is of the paper covered flash hole type and also made by Maxam, as is the propellant powder. The powders are from the Maxam CSB single based propellant range.
They have been selected to give a clean burn with negligible residue while producing consistent ballistic performance within the relevant pressure limits; both gave quite brisk velocities with the 24 gram just a shade quicker than the 28 gram, although the difference is too small for the shooter to notice.
The propellants used are efficient too, producing the required energy with powder charges of just 23 grains (in 24 gram) and 24.3 grains in the 28 gram load.
The lead shot used in both was closer to UK 7 than 7.5 but is correct to the 2.37mm marked on each cartridge and confirmed by the pellet counts per ounce. Well polished and graded for size, the bulk of pellets were close to this size and the CV reading of 30% indicates a hard shot sample, in the mid-range competition region of 3% antimony.
The unique wad
So, on to the unique component that makes the Bio Sport cartridges special! The Jocker Bio wad is made of paper, fibre and cork, and is made up of four main components:
- A sturdy paper or cardboard tube
- A cupped cardboard gas seal
- A fibre wad with cork discs attached at each end
- A plain card disc between the gas seal and fibre wad
The main tube has the fibre wad glued inside its base. On occasions an odd pellet or two were found in recovered fired wads; these had, it seems, been held in place by a little excess glue. I gather that steps are already being taken to refine glue application and add some other ‘minor tweaks’ to further improve performance.
Different length fibre wads are used to adjust the internal capacity for the different shot load weights. This allows the same tube to be used for the 28 gram, 24 gram and other shot load cartridge wads.
I noted that the cardboard tube is thicker than that of the early prototype wad I saw. Jocker confirm that this is to ensure the tube is sufficiently strong to be used with steel shot cartridges.
Indeed, I’m told this is the wad used in the Jocker steel shot cartridges we fired at a recent ‘try steel shot cartridges’ day organised by BASC at Oakedge Shooting Ground. I can confirm that they worked very well that day!
With almost all plastic cup wads the shot cup typically comprises four separate ‘petals’; these are usually formed either by being injection moulded that way, or a complete cup subsequently cut with blades as the wads are loaded.
Lead shot loads mostly use moulded type shot cup petals and steel wads are cut. The difference being that there is virtually no gap between each petal when the cups are cut – but is an extra operation and blades must be kept sharp. It doesn’t matter if any lead pellets squeeze through the gaps in moulded petals but it might with steel shot.
At first glance the Jocker shot cup appears to have no petals at all; however, closer inspection reveals another novel approach that makes the shot cup suitable for use with lead or steel shot. The shot cups are internally cut, with eight partial depth cuts that leave the external surface unmarked.
This must be a very precise operation to perform; the result is eight potential segments to open up once the wad and shot has left the muzzle, retarding the wad so it falls away from the shot load. Recovered wads showed that it doesn’t always result in the petals opening evenly but rather strips of card are torn away.
Sometimes the wad is found entire; this also happens with some plastic wads too, especially if the bands holding the petals together for loading purposes do not break as intended.
The internal fibre wad has cork discs glued on at either end. This gives added cushioning to the shot and possibly a little extra compression to achieve good crimp closures. The shallow cup gas seal base is very important as it has a lot of work to do.
The prototype sample I first saw had a plain cup. I suggested that making the cup with a ‘corrugated’ form should allow it to expand better without tearing; I had seen this principle used in some Winchester Skeet cartridges many years ago and it worked well. I was therefore pleased to see the actual production version of the Jocker fibre wad has a corrugated gas seal.
It is quite a complex design and I admire the work that has gone into making this, seemingly simple but difficult to produce, wad in quantity. As you would expect, this Jocker design is protected by patent!
Jocker have also rather cleverly made use of the clear cartridge case and the white wad. All the information of make, type and shot size is printed onto the wad, not the cartridge case. It’s easy to read and will never rub off – how smart is that?
Can they perform?
Both were submitted to the Birmingham Proof Laboratory for pressure, velocity, momentum and consistency testing to CIP standards. Patterns were fired through a test gun with standard bore size barrel and conventional, short, forcing cones.
The Proof laboratory reports clearly show that these cartridges achieved ballistic performances that sit well within that expected of competition grade cartridges. Both produce sensibly brisk and consistent velocities right around the region also occupied by many established premium grade cartridges; plenty fast enough to do the job without being ultra fast.
Good consistency also indicates that the combination of fibre wad, tube and gas seal performed well together. Pressures are well under the limit. Momentum figures are moderate which helps with comfort; I found the 24 gram load particularly smooth.
Patterns for both also achieved average densities that slightly exceed the nominal (65%) choke boring of the test gun, the 28 gram by a slightly greater margin than the 24 gram.
The lighter shot loads with the same shot hardness, and similar speed usually gain a percent or two over the heavier shot load. This can close the gap in actual pellet count in the pattern, which is obviously reduced with lighter shot loads.
The recent outing at the steel shot trial day was fresh in my mind when these lead shot Bio Sport turned up for review. I had been well impressed by the 21 gram steel shot load Jocker Bio cartridges tried that day; others in my small group were impressed by them too, with convincing kills on driven and quartering clays.
I tried Bio Sport 24 and 28 on DTL and Sporting targets. The 24 gram broke first barrel DTL targets well, and some second barrels. The 28 gram, eligible in DTL, pulled second barrels back just that bit more convincingly.
I found much the same with Sporting clays; driven and incoming and away quartering clays all convincingly broken when properly centred. Again, on the longer, smaller profile quartering targets I found the 28 gram loads gave me a bit more distance.
A game changer
These new cartridges could be the game changer that clay shooters seek, especially if you’re one of those who feels at a disadvantage when having to use fibre wad cartridges.
As well as my normal gun, I tried the Jocker Bio Sport in a new gun with lengthened forcing cones. This gun had exhibited some shot load disturbance with conventional fibre wads, with patterns containing more pairs, triples and even occasional small shot balls.
There was no sign of such gas disruption with the Jocker Bio Sport cartridges, nor any heavy lead fouling. I intend conducting more tests on long cone guns in the future as it looks as though these could be helpful for those looking for a fibre wad load to use in their extended cone guns.
In summary these cartridges gave a very good account of themselves. Not only do they perform well, they have a very reasonable retail price, especially for ‘eco-friendly’ cartridges.
I can see a great many more Jocker cartridges appearing on clay ranges soon. There may be a small wait though; the importer had sold out of the first consignment when I enquired!
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