Potentially stupid 6 Dasher freebore/OAL question

[BoilerUP]

Let's say we have formed 6 Dasher brass that is 1.554" long.

Let's also say we are using a 6mm 105 Hybrid, with a nose length of 0.701", and our chamber has 0.104" freebore.

If we assume 1.554" long brass and 0.104" freebore, is it safe to say that the cartridge BTO is going to be 1.658" just touching the lands and with a 0.701" nose the cartridge COAL just touching the lands will be 2.359"?

I know one should use actual measurements...just want to make sure my math reasoning is sound.

Thanks in advance...

 

[rcw3]

Let's say we have formed 6 Dasher brass that is 1.554" long.

Let's also say we are using a 6mm 105 Hybrid, with a nose length of 0.701", and our chamber has 0.104" freebore.

If we assume 1.554" long brass and 0.104" freebore, is it safe to say that the cartridge BTO is going to be 1.658" just touching the lands and with a 0.701" nose the cartridge COAL just touching the lands will be 2.359"?

I know one should use actual measurements...just want to make sure my math reasoning is sound.

Thanks in advance...

Sorry - the math reasoning proposed is not sound.

Not sure you can ever do it the way you are proposing and have it come out within .030" or so of the math.

First off - - you're running off the brass (not the chamber) to the lands so that's an issue right there - - in a chamber you have from the end of your brass to the "max chamber" dimension that you would need to add on, plus you have the length of the 45˚ section forward of the end of the "max chamber" section to the place where the "freebore" then begins, plus you also may have the tolerance issues (go - no go lengths) and plus (usually +.005) reamer length tolerances. These are just a few of the variables, but if bore size or diameters vary a few tenths (which they do) that can skew things a lot when you only have a 1'30" throat angle (if that's what you have, and it could all be different if you have a different throat angle).

Bullets vary, tooling varies, bores vary so there's a whole lot of variables that the numbers don't factor in - - take an actual measurement.

Just guessing, but with some careful math and some more added in factors you might hit it within .030" or so.

 

[BoilerUP]

Thank you for that; I appreciate the education!

"Learning has occurred"...