Grant and all - back in the 90's, when I used to take my students to the MoD Pattern Room, first at Enfield, then at Nottingham, I was lucky enought to make a firm friend of the curator, the late and much-missed Herbie Woodend, so I was often able to make visits there without a tail of studes. It was on one of these occasions that Herbie invited me to help him to open a large box that had been sent from Parker-Hale, then in the process of winding up. To my astonishment, it was the original set of pattern gauges for the P53 rifled musket, used by P-H to replicate the entire series of rifles based on that basic action and stock dimensions. Parker-Hale had finally been pursuaded to return them to the Pattern Room. Needless to say, a lot of counting and checking went on that day - P-H had had them for well over 20 years - 'on temporary loan'. And of course we played with the priceless bits. Taking one of P-H fine replications out of the store, we set the lock in the original gauge, which had hardened steel pegs where all the various bolts fitted. It was a perfect fit - not a pretty good fit, but a perfect fit. As, in indeed, was every other piece of the P-H version. A few years later, we tried the same exercise with one or other of the Italian replicas, made after P-H had sold all the bits on to stave off bankrupcy.
Not one of the parts was anything more than a reasonably good fit, but the lockplate did not fit anywhere. Production creep is what it is called in industry.
tac
