I've just stripped one of the later Paratroopers as the spring was feeling pretty feeble compared to another one that I have. The existing spring is 19.4/13.3 3.1 30 coils. Its 210mm long but looks quite compressed towards one end.

I bought a Titan XS No.13 for it but its too small. On paper the ID looks to be too tight for the spring guide and the actual item is a little smaller in OD than the published specs. Bit disappointing as its listed for the Paratrooper.

Any other sources for a spring please?