I am following this topic with interest as there is much excellent information here. I well remember the debate over the LGU TP and how it was best to open it out to 3.2mm for a better performance and, if I remember correctly, to avoid stress on the factory fitted mainsprings.
But I digress. In reading these posts, someone could be forgiven for thinking that manufacturers have got it all wrong ... usually using TPs that are too narrow or, in some cases, too wide for peak efficiency. I have been pondering why this is ... There are several explanations amongst which is the possibility that the manufacturer chooses a TP size without any real research into its performance; a case of 'oh, that'll do'. Or the chosen size may be a production based compromise to use one size for different markets rather than matching a size to a particular market. Did not Walther do that with the LGU with the TP for the USA market being larger than that for Germany (and the UK)? Or maybe the manufacturer tries to provide a solution by using a TP restrictor (K98?).

Thank heaven for people like those on here who do the hard work for us.

Cheers, Phil