It wouldn't hurt to have Holland look at it. The gun being in the UK it has to be in proof to make a sale, no? Personally I wouldn't want a paradox with wall thickness at.022. I haven't tried the H&H ammo but have heard mixed reviews on it. The date of the gun would make one think a standard paradox load would shoot well in the gun and perhaps the H&H load as well which is said to mimic 30gr cordite load.. With a paradox, the magic is all in the barrels.