GUNSMITHING SERVICES: 8-40 base hole receiver threading

An unfortunate side effect of production-grade receivers is the tendency for certain features to be machined slightly out of position.  Our 8-40 optic base hole upgrade is intended to resolve this issue, additionally, it can also add base holes to receivers that were not originally machined for them. (1903 Spgfld, Mauser, etc...) By aligning the receiver bore parallel to the machine's work environment, we can correct positional errors on existing holes already in the receiver.  The traditional process is to chase the existing holes with a drill and complete the job by tapping to the 8-40 thread pitch size. LRI does not follow the drill/tap process.  Instead, we bore the existing holes to size using an endmill.  Doing so ensures that the bore center is truly at the desired location.  Drills struggle to correct a positional error of an existing hole. Boring ensures ensures both the location and size.  Next, we use Thread Milling to machine the threads that the fastener will engage with