I recently did some maintenance on my Retal, and aside from all the dirt, I found one slight issue with the long term use of stock internals, which that the bolt eventually crushes the edges of the webbing inside the front of the piston head where it makes contact. Bit a design flaw if you ask me, it's an extremely small area to take the full spring force on priming and even with a stock spring the loading there is bound to cause plastic deformation of the edges of that webbing, and eventual trouble as that is a critical dimension.
In this instance, the catch engagement had started to get a bit less certain as the webbing collapsed and the bolt carrier hit the end of its travel.
I Devconned a disc of approximately 1/32" scrap ABS in there on top of the webbing. Problem solved. No more of the bolt end munching into that webbing and a little extra margin for catch engagement than stock.
I haven't chrono'd it yet, but the amount of added mass is very small and some dead volume (inside the webbed area) is also eliminated since I made sure it was sealed around the edges.