I have gotten both good and bad repro parts from both Sarco and Numrich...
Sarco had some excellent repro artillery barrels a few years back (I came into possession of one) but OTOH Numrich had a nice looking sear spring for a C96 that only worked once...(Bad or no heat treat)...
Numrich also sells cast flash hiders for Enfield No5 carbines that come with an oversize sight blade dovetail - OEM front sights don't fit (way too loose) and no one seems to offer oversize blades to fit it, making them pretty much useless...
Unless you're able to machine your own...
Repro parts are a crap shoot...