Freebore measurement

[ratbuster]

Does freebore length include both the length of the throat and the additional approximately .015" long taper that starts at the end of the neck that transitions to the throat?

I want to make sure I'm reading reamer print dimesions correctly

Thanks

 

[Hopkins]

I think the definition may be open to opinion. To me, it means the distance between the end of the chamber relief for the neck to the point where the bullet engages lands which will include a portion of the leade.

 

[WSnyder]

No it would not use the 45° taper ahead of the neck as part of the freebore/lead dimension.

In my experience if you are communicating with a reamer manufacturer and say .199" freebore, that dimension will be understood as the lead dimension on a print.The lead dimension only includes the parallel (or close to parallel in some chambers) portion of the chamber between the end of the 45° after the neck to the beginning of tapered portion of the throat. If you use any other combination of dimensions and verbally use that number as freebore you will not get get what you think you'll get on your reamer. This is pretty universal with all of the reamer makers. That is also the reason reamer makers generally require an approved print for a custom reamer so there isn't any miscommunication. In the picture example the lead dimension for a SAAMI 6.5 Creedmoor is .199" and that is generally understood in communicating with a reamer maker as .199" freebore.

 

[ratbuster]

Thanks for the clarification Mr. Snyder.


Phil

 

[dmoran]

@WSnyder has it correct.
I deleted my reference, which was wrong.
Donovan

 

[ratbuster]

Donovan,

I have read many of your posts; you are quite knowledgeable. When I saw that I knew you knew better and were a little quick on the draw there.

Phil

 

[Dgd6mm]

I was just saying yesterday how I would like a better understanding of how to read reamer prints.