Like I said I'm an amateur amateur machinist so I will attempt the 80 then, if successful proceed to the zero.
Every time I throw a ruined piece in the scrap bin I say, "Well I learned something and I can make something smaller out of it". The Wife is an advanced spinner and knitter. She often, after many hours of knitting, will unravel the work and start over and start over if it is not exactly to Her liking. She says that is necessary to get it right. Damn I wish I could that with metal.
Like I said I'm an amateur amateur machinist so I will attempt the 80 then, if successful proceed to the zero.
Every time I throw a ruined piece in the scrap bin I say, "Well I learned something and I can make something smaller out of it". The Wife is an advanced spinner and knitter. She often, after many hours of knitting, will unravel the work and start over and start over if it is not exactly to Her liking. She says that is necessary to get it right. Damn I wish I could that with metal.
Something else I forgot to mention. There is a half truth out there that dry firing a firearm will somehow damage it. With RIMFIRE cartridges like the 22 family and the newer 17 family of small caliber rimfire ammo, this is true. The firing pin actually contacts the edge of the barrel and can damage it, the firing pin of both. SO if you are building a rimfire AR don't get crazy dry firing it.
Center fire cartridges do not have the same issue. Because the primer is in the middle of the cartridge the firing ping design is different. The pin can't hit anything with the tip. and most center fire firearms have a well retained firing pin that has a large surface to strike when dry fired to spread the impact out and not land it all on the tip of the firing pin.
Jigs are for those who do not have lay-out skills
I've found the jig to be more of a hindrance than of benefit.