how much case bullet contact do you need?

[lucho]

I have a 7BR and want to shoot the Sierra 175gn bullets. And I want to seat them long.

What is the minimum length of case to bullet contact I should have?


Is there a general rule about the length of the case to bullet contact? Maybe one diameter?

I'm not even sure what to call this length. It's not how far the bullet sticks out but how far it is in the case. Not including the boat tail, which doesn't contact the case.


Thanks
Lucho

 

[expiper]

You will have no choice on the seating depth ...make them as long as the freebore will allow......
Or are you wanting to know the freebore length for a new reamer which will allow the bullets to be seated long.???...
The old wives tale of one bullet dia. for seating depth is not always possible or practical.....my BR has seating depth lengths,shank) from .255" for the 107's to .120 for Bart 68's ...and they all shoot great...remember ...the bushing style dies only size aprox. 180 of the neck length...so the rest is just hangin out in outer space any way!!! ...Roger

 

[Jeffvn]

If I understand your question you are asking if there is a rule of thumb regarding how much of the bullet shank should be inside the neck of the case.

I have always heard one caliber is the optimum. ,For a 7mm chambering it would be .284"). But, milage will vary, expecially if you are going to seat the bullet into the lands.

JeffVN

 

[lucho]

Thanks JeffVN

That is what I was wondering.

Has anyone else heard any different?

Lucho

 

[billmo]

lucho, according to all that I have been able to read, that is pretty much the general, but as mentioned sometimes when trying to seat your bullet close or into the lands you would not be able to achieve both. Personally, I have loaded quite a bit for Rem. .308 SV rifles in the past and they all seem to have very long freebore areas. I have loaded many times and not have much over @ .100 of actual bearing surface of the bullet touching inside of the case neck and shoot some pretty good groups for a factory rifle so I don't think there is any penalty for loading as such. Just my opinion from past experience. Bill