Punching above their weight

These two 21gram clay cartridges from Rio offer tremendous performance and value for money, says Richard Atkins.

The cartridges put through their paces this month are the lighter shot load versions of the Rio 28 gram Target Load cartridges we reviewed last year. Offering lighter recoil and budget pricing, they are well presented in the same sturdy, bright blue cartons of 25. As we will discover, the shot load may be less, but these are certainly no slouches in the velocity department!

We’re looking at the fibre and plastic wad types. Both are loaded into the same bright blue parallel tube plastic and lightly ribbed Maxam cases, with 12mm high brass plated steel heads, as in the 28gram version.

One difference is that the case length is reduced to 67mm (from 70mm) for the fibre wad load. Shot load weight, case length and velocity are all clearly printed on each cartridge.

The loaded cases are closed with six-point star crimp closures, with the plastic wad version very crisply formed with a smooth, tight, turnover. The fibre wad crimp proved a little less precisely formed than the plastic wad version; something that can happen with fibre wad cartridges as they are more technically difficult to load. The Proof Laboratory reports revealed that this had no detrimental effect upon ballistics.

The shot size is stated as 7.5 and, as a rule, Spanish shot sizes are very similar to UK sizes in this size range (whereas Italian cartridge shot sizes are typically half a size larger).

This is, however, an area where confusion can arise because some conversion charts compare UK shot sizes to ‘Continental’ sizes, and not all ‘Continental’ sizes are equal!

It might, therefore, be an idea for Rio to add the actual shot diameter, alongside the size designation, as many Italian brands do. This is one reason why we always check shot size in our test procedure.

Plastic wads

The wad in the plastic wad Target Load is the highly regarded Maxam ‘A’ type 28 series wad. Design is essentially the same as the 28 gram version but with a shorter shot cup. The shot cup has pre-formed leaves lightly joined with fine tabs to prevent cups becoming tangled during the wad loading process.

The plastic wad’s multi-layer tubular honeycomb centre section has the same number of cushioning layers (four) as the 28gram wad, but with larger diameter lateral tubes, each layer separated by a thin disc to produce the multi-layer shock absorbing centre section.

This gives extra height for the lighter shot load in the 70mm long case. It also provides a lot of shock absorption to reduce compressive deformation damage to the lead shot pellets upon acceleration, and helps reduce felt recoil. This wad design is used in other Maxam stable cartridges, including Eley, who use it in their premium Titanium range.

The fibre wad cartridge is loaded with the widely used Diana one-piece fibre wad. This one is 20mm long (against 18mm in the 28 gram load) with a vegetable fibre main body, with black laminate coating at each end which prevents pellets becoming embedded into the wad.

A strong, 4mm thick card wad is seated under the main wad for better gas seal, and preventing ingress of wad lubrication affecting the propellant powder.

Rio Target Load 21 Gram 7.5 Plastic

Shot load: 323 grains
Pellet (count per oz): 363
UK shot (size/cv): <7 / 29%
Pellets in 30in Circle (avg): 178
Pellets in 20-30in: 78
Pattern: 66%
CD: 55%
Velocity: 416m/s (1,365 fps)
recoil: 8.7 Ns
Pressure: 490 bar

Rio Target Load 21 Gram 7.5 Fibre

Shot load: 325 grains
Pellet (counter per oz): 335
UK shot (size/cv): 7 / 34%
Pellets in 30in dia (av): 48
Pellets in 20-30in: 64
Pattern: 59%
CD: 57%
Velocity: 421 m/s (1,381 fps)
Recoil: 8.8 Ns
Pressure: 622 bar

Powder and shot

Propellant powders in both wad type cartridges are from Maxam’s CSB range. These are single base, disc flake, high energy nitro cellulose propellants designed to give clean and consistent burning with minimal smoke and residues.

Powder charge weights averaged 19.7 grains in the plastic wad type and 21.4 grains in the fibre wad load. The velocities printed on the cartons indicate that the plastic wad gives 420 metres/second and the fibre wad 415 metres/second: these figures are well into the ‘High Velocity’ category.

A shock-absorbing centre section in the plastic wad helps reduce felt recoil
The fibre wad is the Diana type, with a card wad underneath for a better gas seal

These 21gram Target Load cartridges are currently offered only in shot size 7.5. Pellet counts revealed that the sizes were not quite the same in each cartridge type – which is why pellet count should always be checked when undertaking meaningful pattern testing.

The 363 pellets per ounce in the plastic wad load is about half way between UK size 7 and 7.5 (UK 7¼). The 335 per ounce in the fibre wad load is very close to UK size 7 – so both proved larger than UK shot size.

The hardness or Crush Values were similar to each other, at 29% for the plastic wad load and 34% (slightly softer) in the fibre wad load. These are close to the figures for the 28 gram loads and indicate around 2% to 3% antimony content.

Pellets were reasonably well graded for size, with size variation for both samples mainly within 0.005in. All were well polished with graphite for a shiny black surface.

These Rio Target Load cartridges were submitted to the Birmingham CIP Proof Laboratory for pressure, velocity and momentum testing. Pattern tests were conducted at 40 yards from a 30in long, standard bore size barrel with 2¾in (70mm) chamber with standard length (short) forcing cone and bored Imp Mod choke (UK three quarters). Additionally, patterns were also tested at 30 yards. 

Performance

The laboratory reports confirmed that velocities are indeed high. In fact, the fibre wad load gave the slightly higher velocity of the two, which was unexpected.

These velocities still gave very modest felt recoil thanks to the low momentum figure with the lighter shot load. Note that the pressure in the plastic wad load was significantly lower than the fibre result, possibly indicating a slower burning CSB powder.

At the standard 40 yards, the plastic wad load slightly exceeded the nominal Imp Mod pattern
At a closer range of 30 yards, the plastic wad placed an impressive 264 pellets in the 30in circle

The lower sectional density of a 21gram shot load helps reduce compressive pellet deformation and hence tends to keep more pellets within the useful pattern; this is why lighter shot loads often perform ‘above their weight’.

The modest pellet hardness and high velocities appear to have counterbalanced the low sectional density effect to a degree, but would have been less noticeable if the pellet count per load was higher. 

Nonetheless the plastic wad load still managed to slightly exceed the nominal Imp Mod (65%) pellet density result at 40 yards, with a 66% average density.

The average fibre wad result was more open, at 59%, which is nominally a Mod (half) choke pattern density. The high velocity was no doubt a contributing factor.

This helped confirm my personal preference for UK size 8 shot in 21gram cartridges. This is because pattern density will increase, and while pellet energy will be lower, it should prove adequate for the types of target most likely to be tackled with lighter shot loads.

I shot some Sporting clays with the fibre loads and both Sporting and DTL (first barrel) with the plastic wad – and got on rather well with them. The reason is quite simple: the majority of the targets I tackled were less than 40 yards away.

At 40 yards the fibre wad shells gave a half choke pattern from the Imp Mod barrel
At 30 yards the fibre wad gave an even pattern with 215 pellets in the 30in circle

Clays are often closer than many shooters perceive, and for this reason I also did some 30 yard patterns before rain stopped play. These obviously produced much more dense patterns. The fibre wad achieved an average of 215 pellets in the 30in circle and the plastic wad an impressive 264 average.

These equate to Mod choke and almost Full choke results respectively from the same test barrel, and helps explain why breaks were positive. It was interesting to see the considerable difference that 10 yards makes – probably more than those who don’t pattern their gun and cartridge combination might expect.

Give ’em a go

I can confirm that these light loads, with their combination of low recoil and high speed, give a very pleasant shooting experience with good feedback and effective results. Some 28gram loads, even those 20 metres/second slower than these, definitely feel more ‘punchy’.

You could easily shoot 100 or more of these and feel no after effects in a typical clay target O/U. Even in a side-by-side or light O/U they will make for a comfortable day’s clay shooting. They also cycled reliably in my Winchester Super X gas operated test gun.

If you like a cartridge that gives a crisp, fast response with minimal recoil, all for a budget price, you might well like these light Rio Target Loads. The only way to know for sure is to try some.

The plastic wads are the same design as those used in some Eley shells, including the Titanium
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