Neck sizing and clearances?

[SparkyHD1]

How much clearance do I need between my neck and chamber?
I have a 7mm with a .314 chamber and want to order a neck bushing, so my way of thinking is that I would need a .310 bushing to give me .002 clearance in the chamber and .002 neck tension?
Should I go with less clearance?
Or am i way off on my calculations?
This neck turning and bushing does are new to me. I would Appreciate any help i can get

 

[47guy]

You need to measure the neck on a loaded round for your measurements to get the correct bushing...if you want .002 tension go .002 less than your loaded neck size

 

[SparkyHD1]

You need to measure the neck on a loaded round for your measurements to get the correct bushing...if you want .002 tension go .002 less than your loaded neck size

I do understand that. I'm trying to figure out how much clearance I need between the neck and chamber?

 

[idahoorion]

Sparky, you need to load a round, with your chosen brass and bullet. then measure the neck in a few places. the bullets vary slightly from one to another but the brass especially between brands can vary a lot. if you have less than 2.5 to 3 K clearance between your chamber neck and your brass with a loaded bullet you may be needing to turn necks or to change brass. you can get by with less but you have to be clean and be careful. if you have less I would be consulting your gunsmith.

Idahoorion

 

[SparkyHD1]

Sparky, you need to load a round, with your chosen brass and bullet. then measure the neck in a few places. the bullets vary slightly from one to another but the brass especially between brands can vary a lot. if you have less than 2.5 to 3 K clearance between your chamber neck and your brass with a loaded bullet you may be needing to turn necks or to change brass. you can get by with less but you have to be clean and be careful. if you have less I would be consulting your gunsmith.

Idahoorion

Okay, so I'll
1) measure a loaded round
2) determine how much I have to turn the neck to achieve. 2 1/2 - 3 thousands clearance (Which should take the neck to .311)
3) then get a bushing .002 smaller to set neck tension, which should be. 309?

 

[SparkyHD1]

Sorry, I probably didn't do a very good job explaining that. I think I understand.
This is the first time owning a tight chambered rifle where I had to turn the necks. A loaded round is .316, so won't even fit in the chamber without neck turning.

 

[spife7980]

I think you understand it by what you said in post 5. Just realize the bushing is dependadnt on the loaded round diameter. As for how much clearance that will be dictated by how much you turn off.

.314-.284=.030/2=.015 of brass wall on each side for a press fit. For the .003 of minimum clearance (safe minimum amount imo) you would need to turn your brass to .0135. That will leave your loaded round at .311 like you said.

 

[47guy]

I do understand that. I'm trying to figure out how much clearance I need between the neck and chamber?

sorry i miss understood you but spife7980 has you covered and as Idahoorion said make sure you keep an eye on your necks.