I remember the setup at Enfield for L1 production. Receiver forgings were brought in and a lot of the machining was done on a number of Weatherly Oilgear slab broaching machines brought in for the job, the installation for which can't have been cheap. The machines were upright and stood in pits with roughly half the height below ground. There was an overhead hoist system for fitting and removing the broach bars and a pumped cutting oil supply plus a special grinder used to resharpen the broachs.I have to apologise regarding the casting/forging.. I obviously had a brain fart at that point, however I suggest my contention still stands in that the setup cost for forging is high and is only economic for long production runs..