RC7 cartridges on test – ‘The One’
Richard Atkins examines and tests the RC7 cartridges called ‘The One’, available in both plastic and fibre wads
RC7 The One cartridges
RC7 The One cartridges
We can be assured that any new product from Romagna Caccia, now RC EXIMPORT and known worldwide by the initials RC, will be of interest, so we thought we had better take a close look at the new RC7 The One cartridges.
Since the company was founded in 1970, RC has built up an impressive catalogue of successes in major international competitions, ever since Luciano Brunetti won gold in the Skeet World Championships in Seoul in 1978 using RC1 Skeet cartridges. (Read more about skeet shooting here.)
World and Olympic medals have followed to the present time. Perhaps most memorable was Michael Diamond taking the Olympic Trap gold medal at the Sydney Olympics in 2000, using RC4 Champion Excellence cartridges.
Closer to home, Peter Wilson won Double Trap Olympic gold at the London Olympic games using RC4 Champion cartridges and Giovanni Cernogoraz took Olympic Trap gold using the same cartridges.
The pedigree of RC products is well established and appreciated by the world’s leading shooters. Obviously, for most of us mere mortals, we don’t necessarily require the absolute ultimate in cartridges but it’s nice to know they are available.
- Configuration Target Load 28 gram 7.25 shot fibre wad
- Shot load 432 grains
- Pellet (count per oz) 318
- UK shot (size/CV) 6.5 / 24%
- Pellets in 30in dia (Av) 111
- Pellets in 20in to 30in 87
- Pattern 63%
- CD 56%
- Velocity 399m/sec (1309fps)
- SD 5.5
- Recoil (M) 11.2Ns
- Pressure (bar) 630 bar
High competition cartridges
These new RC7 The One cartridges sit just a shade under the ultimate RC rounds mentioned but are still pitched as high level competition cartridges. Indeed, the strap line on the RC web site describes them as “oltre la perfezione”, which translates from Italian to “beyond perfection”. That’s a bold claim and makes examining them extra interesting. We have the plastic and fibre wad 28 gram cartridges for review.
Quality cartridges require top grade components and meticulous assembly on state of the art loading equipment. RC prides itself on always being at the leading edge of technology and equipment.
The first thing you notice is the strikingly bold and smart design of the RC7 The One cartons of 25: the glossy red, white, black and grey boxes stand out, as well as protecting the contents. Shot weight and size, including the metric shot diameter, is clearly printed too.
The 70mm black plastic parallel tube cases have 20mm high, nickel plated steel, head. Loaded cases are closed with very tight, neat and uniform six point star crimps. Tight, consistent crimps are another requirement for maximum performance and consistency.
The specially selected primers have their flash hole sealed with lacquer which ensures the priming compound will not be affected by changing atmospheric conditions and no powder granules can enter the primer cup to affect ignition.
Propellant powders are both single base and from the Nobel Sport Italia range but of different types to suit the different wads. The plastic wad RC7 is loaded with 21.2 grains of the light green, small square cut laminate, C7 powder.
This is a high energy powder as the high velocity for a modest charge weight shows. It is fast burning too, which produces a fast pressure climb and swift pressure decay. This follows the principle I first experienced many years ago with Remington RXP cartridges.
This has the interesting characteristic of helping some shooters (not all) to perceive a smoother shooting experience with reduced perceived recoil.
The actual dynamic recoil must be the same as any other cartridge propelling this weight of shot at the same velocity as RC7; however, due to what has been explained as speed of pressure build up decay, some shooters find this formula smoother to shoot. I certainly did; all those years back when 32 grams was the standard Skeet shot load.
The fibre wad load uses the pink in colour and larger square cut flake laminate Vectan powder for 28 gram loads. This is a slightly more progressive burn powder, as the lower breech pressure indicates. The charge weight is higher, at 23.5 grains but this is always the case with fibre wad loads as they are less efficient than plastic wad loads.
The extra 2.3 grains produced a mean velocity which is nominally identical to the plastic wad load.
Both powders burned very cleanly, with minimal visible residue with the C7 perhaps a fraction more ‘mirror like’ in cleanness of the bore after firing.
The main driving wad is an 18mm tall Diana fibre wad with plastic laminate end faces to prevent shot pellets becoming embedded in the wad. It is lightly ring greased to improve gas obturation.
The plastic wad, which is patented, follows the ‘honeycomb’ design central section with solid support disc below. This gives good support to the gas sealing skirt at the base.
The shot cup is novel in that it has eight petals. These are knife-cut into the cup and not moulded in as most plastic cup wads with four petals are.
This should ensure that the shot cup opens rapidly and evenly on emerging from the muzzle and so remove any chance of the wad interfering with shot pattern development.
Examining recovered fired wads showed that this is what happens; the wads travelling straight and a very similar distance. The pattern pellet counts were among the most consistent, shot to shot, that I have ever recorded so all worked very well. And consistency is what you need when competing at high level.
The shot loads in both wad types is described as ‘selected tempered lead shot’. It is hardened with a high antimony content and precisely graded for evenness of shot size: that is what close examination confirmed.
The fibre wad is marked as 7¼/2.45mm diameter shot size and the plastic wad 7.5/2.40mm diameter, these being Italian sizes. I’m not entirely clear why the small difference in shot size, given that both types have very similar velocity, but it does of course affect the number of pellets in the shot load and hence the patterns.
My shot crush tester confirmed that the pellets are hard, with at least 4% antimony, and both sizes gave almost identical hardness CV results.
The lead mix is likely the same for both and it is just that the slightly larger pellets in the fibre load will give a marginally reduced crush percentage.
In both sizes the actual grading for size proved very close, which helps keep shot strings compressed. Pellets were all well polished with graphite.
Ballistic results were obtained from the Birmingham Proof Laboratory and the RC CIP regulated proof facility.
Pattern tests conducted at 40 yards from a 30in long, standard bore size (0.729in) barrel with 2¾in (70mm) chamber and standard length (short) forcing cone, bored Imp Mod (UK ¾) choke.
The results show that these are, indeed, very high performance cartridges. The velocities for both types are very close to 400 mps and consistent.
This is a figure many shooters and cartridge loaders consider a practical, effective speed. It gives all the pellet energy required to break long distance clays whilst keeping a balance with recoil so that concentration can be maintained. The momentum figure of around 11Ns gives a recoil energy that most will feel comfortable with in a good weight clay target gun.
The plastic wad load performed very well and produced a 69% average pellet density at 40 yards. This equates to a nominal tightening of the (nominally 65%) Imp Mod (¾) choke test barrel.
This is what quality shot and excellent wad can achieve, even when pushed to 400mps. As often the case the fibre wad load with the same hardness of shot, didn’t quite match up and pattern density just slipped below the nominal test barrel percentage at 63%.
Note the effect of the shot sizes too: the fibre wad put 198 pellets average count into the 30in circle at 40 yards to the plastic wad average of 246. Clearly there will be fewer gaps in the overall pattern with the higher pellet density.
This is something one can see when testing on clay targets. I set up my clay trap to throw DTL type trap targets but travelling a bit further and faster than DTL speeds. Both types coped well enough. As I moved back to stretch the distance, it became more noticeable that the plastic wad load was producing more positive smashes at range.
The fibre wad still broke targets at range but with larger pieces whereas the plastic wad was still crunching them. The bigger pellets had the energy but being hit with more pellets, with adequate energy, proved more positive.
No surprises really. This testing was to compare two different cartridges. It is highly likely that upping the choke would extend the range at which the fibre wad RC7 would give good breaks. And this is why it pays to pattern your gun with your chokes and the loads you intend using.
- Configuration RC7 THE ONE Target Load 28 gram 7.5 shot plastic wad
- Shot load 434.5 grains
- Pellet (count per oz) 361
- UK shot (size/CV) 7¼/25%
- Pellets in 30in dia (Av) 246
- Pellets in 20in to 30in 98
- Pattern 69%
- CD 60%
- Velocity 400m/sec (1,312fps)
- SD 4.4
- Recoil (M) 11.2Ns
- Pressure (bar) 708 bar