All cartridges are not the same...

[ChrisPackham]

Personally l think there is something drastically wrong here, even with the most exspensive cartridge verses the cheapest there should not be 30% difference in the score, especially with tried and tested cartridges like Eley and Gamebore, a session at the pattern plate would be interesting. l think you would be better off changing your gun not your cartridges!

Nothing wrong with the gun and the gun fit, I think I’ve just discovered the best and worst combinations...

 

[westley]

I understand where you're coming from but (as I feel certain you know perfectly well) the holes in a pattern don't necessarily mean a missed bird, at least not until you get a little past reasonable range. Before anyone says, I DO believe you can draw meaningful conclusions from a pattern plate and the relative density of one make against the other but it's also important to remember most of our shots are taken well inside the patterns usefulness. Remember for an actual  miss to occur the clay has to find itself in that actual void at the time. 

I have certainly shot fibre brands through my 682e and been surprised how near impossible it was to achieve smokes or crushing breaks but with plastic wads through standard guns 30% just seems a tad on the pessimistic side. I doubt you'd get that variance on even a difficult 60 yard Teal with the worst/best shell combo. 

The ONLY reason that I succumbed to the dreaded pattern plate, was, I used the gun on a driven game day, using my 2 usual brands of cartridges. Suffice it to say my dog was knackered ! 2 weeks later, after the pattern plate job, I switched cartridge brands and was at the same venue. Back to my usual performance, BUT, I was able to walk out and pick them all myself.  So, although I agree with a hole in the pattern is not the end, it can still down a hell of a lot of runners !