Basic Info every 80% builder should have:Front pivot pin - hole drilled with 1/4"
Rear takedown pin - hole drilled with 1/4"
Trigger pin - hole drilled 5/32
Hammer pin - hole drilled to 5/32
Selector - hole drilled to 3/8
Bolt hold-open plunger drilled with 5/32" to a depth of .470"
Trigger guard - left side - drilled with 1/8" through both ears
Trigger guard - right side - drilled with 1/8" through only one ear
Front pivot pin detent - hole drilled with 3/32" to 1.125" deep
Rear takedown pin detent - hole drilled with 3/32" through to detent pin hole
Selector detent - drilled through to selector with 1/8" then countersunk with 5/32"
Bolt hold-open pin - hole drilled to 3/32" with 6" aircraft bit
Stock index hole - drilled with 1/2"
Grip hole drilled - with 7/32"
Buffer stop plunger - hole drilled with 1/4" to .712" deep
Fire control well milled - by .030 with a 3/8" end mill - optionally shave down your parts to fit the undersized pocket.
Rear takedown well milled - by .030 with a 3/8" end mill - optionally shave down the rear lug of the upper receiver to fit the undersized pocket.
Buffer hole reaMed - to 1 1/8"
Buffer hole tapped to -1 3/16" with 16 tpi
Rear takedown pin relief - cut with a 3/8" end mill
Grip hole tapped - with 1/4" By 28 tpi
This site is very helpful:concealcarry.org/ar15/bs-home.htm