Found The Dimension Answer

[Sparky_NY]

I found out why so many different dimensions are found for .40 case diameter. Case gauges, reload manual data, size die, Fee FCD, factory ammo, ALL different diameters!

I ordered a die from lee yesterday and spoke to one of their tech guys. SAAMI specs are constantly mentioned (.424) BUT the tolerance is almost never mentioned. Per the Lee tech, Case Diameter SAAMI spec,,,,, +0 -.008

Chamber Diameter -0 +.008

That explains it!!!!! Makes sense!

Case gauges are usually .001 under max

Cartridges "try" to run -.003 under max (about middle of the range)

LEE FCD about middle of the range (.421)

My STI chamber +.0005

Worst case Loose tolerances for barrel and cartridge .016 cartridge-barrel clearance

Everyone talks about SAAMI specs, but never mentions the tolerance that goes with the spec!