Neck Measurement(s) Questions

[Gargoyle]

The difference between the OD of a fired case neck and the OD of a loaded round case neck is called____________?

The difference between the ID of a sized case neck in relation to caliber size of bullet is called_______________?

Subtracting case neck thickness and caliber size from OD of sized case neck is called______________?

 

[jds holler]

Hmmmm... Sounds like a trick to me. jd

 

[wildcat3d]

Hmmmm... Sounds like a trick to me. jd

Agreed, But?

 

[Bc'z]

Clearance
Interference
A waste of time

 

[Pres100]

Delta

 

[Ned Ludd]

The term I suspect many would use for question #1 above would be "neck clearance". Technically, "neck clearance" would be the difference between the neck diameter of a loaded round and the chamber neck diameter, as the neck diameter of a fired round is slightly smaller than the chamber due to spring-back of the brass.

I believe the correct term for questions 2 & 3 above is "interference fit", as noted above, the difference being in how the measurement was taken/estimated. The term you will likely most often hear is "neck tension". Although not correct; i.e. we're not measuring "neck tension" using differential diametral measurements, the term "neck tension" is strongly ingrained in the reloading community. In other words, when one provides a diametral difference such as .002" and calls it neck tension, most everyone knows exactly what is meant, even if it is technically incorrect. Likewise, seating force is not a measure of neck tension, even though it should be proportional to neck tension with a couple caveats. There is no easy way to measure a true neck "tension" value, in addition to the fact that such a value is affected by many variables. The term "neck tension" is commonly used simply because it is easy to measure diametral differences, to which true "neck tension" should be proportional, again with a couple caveats. So we determine differential diametral measurement, call it "neck tension", and most know exactly what is meant by that term, even if incorrect.

 

[358WCF]

The difference between the OD of a fired case neck and the OD of a loaded round case neck is called____________?

The difference between the ID of a sized case neck in relation to caliber size of bullet is called_______________?

Subtracting case neck thickness and caliber size from OD of sized case neck is called______________?

Slip fit

Press fit

Zero/null.

 

[Benchrest Braxton]

Can you drop a bullet into your fired cases yet @Gargoyle ?

 

[762plinker]

poor questions not based on real life....

 

[Gargoyle]

Can you drop a bullet into your fired cases yet @Gargoyle ?

Every gun I own. I still need to research what that practice is all about.

 

[Gargoyle]

poor questions not based on real life....

What is real life then?

 

[Benchrest Braxton]

Every gun I own. I still need to research what that practice is all about.

i thought you were one of the ones that couldn’t hahaha.

 

[Dave M.]

Can you be more specific with exactly what you are trying to discern here?? You can choose to call these metrics whatever you want but at the end of the day, what is your goal??

 

[gunsandgunsmithing]

The difference between the OD of a fired case neck and the OD of a loaded round case neck is called____________?

The difference between the ID of a sized case neck in relation to caliber size of bullet is called_______________?

Subtracting case neck thickness and caliber size from OD of sized case neck is called______________?

Three numbers are all you need. Sized neck diameter BEFORE and AFTER seating a bullet.. And chamber neck diameter. You know the answers if you have those 3 dimensions. While common, it also itroduces the most room for error as well as costing more money...stay away from brass thickness measurements. The measurements that matter are all acheiveable and more accurately by measuring the case neck before and after seating a bullet....with a MICROMETER, not a set of calipers. Wrong tool for precision measuring. Beats a tape measure though.

 

[Andy Work]

The difference between the OD of a fired case neck and the OD of a loaded round case neck is called____________?

The difference between the ID of a sized case neck in relation to caliber size of bullet is called_______________?

Subtracting case neck thickness and caliber size from OD of sized case neck is called______________?

I didn't know that there was going to be a test!

 

[Gargoyle]

I didn't know that there was going to be a test!

There's always the one throw away question that's obvious!

 

[Gargoyle]

And chamber neck diameter.

How do you measure that and why does that matter?

 

[Bc'z]

How do you measure that and why does that matter?

Reamer print is easiest way, cerosafe and make a cast of chamber.
Why it matters is the answer to your 1st question.

Clearance

 

[Ned Ludd]

poor questions not based on real life....

The OP is trying to learn. We should be helping to facilitate that process.

 

[Gargoyle]

ID of sized neck .305"
Bullets OD .3085"
.3085" minus .305" = Difference .0035"

OD sized neck .3375"
OD with bullet .3395"
.3395 minus .3375" = Difference .002"

In popular terms of "neck tension" which do I say is my neck tension?