I very much doubt the piston rod is longer. That would mean reworking one of the major parts in this assembly. They clearly have no intention in doing that.

They are mass producing these things to a minimum cost or there would have gone more effort into this than smashing them all together with a load of pressure.

It looks like they have realised that some problems have arisen re loose rods and the odd rod coming out. So the answer is to give it a second smash together.

Not engineering purity ... but if it works it works. They aren't looking to flog Olympic Match accuracy here in these type of rifles. Just mass produced samples that will give most of the world decent enough power from a simple break barrel airgun to pop some tins in the garden or some bushy tails in the trees out to about 40 yards.

Unlike the 'Tune them to the Nth to squeeze another 3% accuracy out of them' brigade on here ... Diana aren't interested in that.

A 2 lb hammer knocks nails in. It doesn't have to be engineered to a tolerance of 0.001". It doesn't have to be Gold plated. You just want it to knock nails in and the head doesn't fly off and kill the bloke behind you. If this extra crushing fixes the safety issue ... it's sorted.