Quote: No,no,no if you make the hole in your comparator .224, the same diameter of the bullet..
Read it again: Quote:...you want the hole diameter to be .224 at the point that the chamfer meets the flat surface of the comparator.
That's correct, you want a chamfer from the thru-hole (< .224) to equal .224 at the plane of the front surface.
Now you can zero out the comparator thickness and get the right reading regardless of ogive shape.
.219 for the thru-hole would work fine, but it's not critical. The bullet gets stopped by the chamfer and never touches the thru-hole anyway. So if I varied the thru-hole by several thou. either way, it would have no effect. Seriously.
Quote:...oh and if you want it accurate you need to hold those diameters to + or - .0005
The only critical dimension is the chamfer depth, actually. And yes, it's very critical that it equals the bullet body diameter when Z = zero.
That's what stops the bullet and is the only point where it will touch. As long as the thru-hole is large enough that it doesn't make contact with the ogive or tip (and prevent it from seating against the chamfer) it won't matter. Making the thru-hole bigger just reduces the depth of the chamfer before it quits cutting.
Quote:nothin like being a machinist !
Do you understand that concept ?
Yeah, actually, I do. 
I'm also sure, being a machinist, if you read exactly what I'm describing, you're going to agree. If not, show me the error in my math.
Quote:just funnin !
You better be! 
If I'm wrong on this, I'm going to be eating some major crow.
