Having seen any number of rebuilt military arms with new action bodies, from G3 type rifles, 1 STGW 57, AK variants what I see is a fair number of them are pretty poor.
In the case of the roller hesitation lock rifles, three defects appear:
1) worn trunions, so they are not unlocking correctly point. In the case of the STGW-57, to the point it was shooting itself to pieces.
2) misaligned trunions, so they do not zero in the adjustment range of the sights (or barely do)
3) poorly heat treated trigger components, which were replaced to allow the arm to sell.
In the case of AK variant, the number of misaligned truinon blocks seems to be pretty high, rarely does one see an AK here in the US that does not have a problem with the point of aim moving as it heats up. I have been told this is due to the need to individually set up each trunion with the associated receiver, but when the manufacturers have made their own trunions form new (like century) there have been numerous cases of heat treatment issues.
The really successful arms were those made by the original factories, with the military quality control NRE covered by the large military contracts for commercial sale. Those are the ones that show up on the range and seem to work well enough to be used in some kind of actual semi match use.
Reading the "last Enfield" it seems that a lot of the defects of the original rifle had to do with the closing of the Enfield facility and the movement of the design to Nottingham, in the point of development where normally new rifles deployed are found to have defects, which are then rectified in the original facility. Added to the difficulties was the cost to manufacturer and the cost charged to the government were out of kilter, so that all sorts of short cuts were made. Had the L85A1 been made in one factory where a long term contract was assured, with a price to match, you would have likely seen a lot of the defects worked out in short order.
The story kind of reminded me of the M14 saga here in the US, which saw the design perfected between 1959 and 1961, by which time the rifles were pretty good. Unfortunately the damage was done that the design was canceled a few years early, with only 1.38 million made by 4 manufacturers. It seems with a service rifle, no matter how much testing occurs ahead of time, it generally takes a few years of production to work out the bugs. The AK, the AR, the M14 and the L85A1 all seem to have had issues on initial deployment, the L85A1
