The correct tools?

[Tangent]

When I'm measuring brass I have a hard time getting the measurements to make sense. I measure a seated bullet neck width, diameter of the bullet and calculate the neck wall thickness. That seems to come out at the same or larger than the mandrel diameter. However I can feel the mandrel doing its work so obviously my measurements aren't accurate.

What tools are you all using to do this?

 

[BoydAllen]

When I'm measuring brass I have a hard time getting the measurements to make sense. I measure a seated bullet neck width, diameter of the bullet and calculate the neck wall thickness. That seems to come out at the same or larger than the mandrel diameter. However I can feel the mandrel doing its work so obviously my measurements aren't accurate.

What tools are you all using to do this?

Do you have a 1" mic. that reads to /0001? If not, I picked up one last year that is both excellent and affordable.

 

[Tangent]

Do you have a 1" mic. that reads to /0001? If not, I picked up one last year that is both excellent and affordable.

No I don't, I suspect that's the issue. Which one did you buy?

 

[old_heli_logger]

There are better ones out there, but this one is working for me. It's a ball micrometer or tube micrometer...the anvil is round for measuring exactly what you're struggling with. Good luck!

Amazon.com

 

[SSL]

Done carefully , a blade type will also work. If I'm reading you right, you are seating the bullet, measuring the case, bullet combo and then deducting the diameter of the bullets...are you remembering to divide that result in half since you are measuring both sides of the neck at once in that instance? Not to be rude, but it is very easy to forget that.
Example - We'll say the measurement of a .223 case neck with a seated bullet mics as .248". Deduct the bullet diameter (.224") and you have .024". Now that includes both sides of the case neck. Now divide by 2 and the actual neck thickness reading is .012".

 

[old_heli_logger]

Done carefully , a blade type will also work. If I'm reading you right, you are seating the bullet, measuring the case, bullet combo and then deducting the diameter of the bullets...are you remembering to divide that result in half since you are measuring both sides of the neck at once in that instance? Not to be rude, but it is very easy to forget that.
Example - We'll say the measurement of a .223 case neck with a seated bullet mics as .248". Deduct the bullet diameter (.224") and you have ..024". Now that includes both sides of the case neck. Now divide by 2 and the actual thickness reading is .012".

After rereading this, you sir, are absolutely correct.

 

[SSL]

After rereading this, you sir, are absolutely correct.

Like with most things, there's usually more than one way to get there!
Have a great day.

 

[dellet]

Sounds kind of normal. The neck diameter will not set at the exact diameter of the mandrel, there is some sprig back. So a .224 mandrel will leave a 2225-223 inside diameter. Minimal neck tension. This can be from using a mandrel intended to be used to size a case for neck turning vs loading. Mandrels for neck tension will be smaller than bullet diameter.

Best way would be to measure neck diameter with the mandrel inserted and again with a bullet. That’s would likely give a better idea of the difference in diameter.

 

[Tangent]

Done carefully , a blade type will also work. If I'm reading you right, you are seating the bullet, measuring the case, bullet combo and then deducting the diameter of the bullets...are you remembering to divide that result in half since you are measuring both sides of the neck at once in that instance? Not to be rude, but it is very easy to forget that.
Example - We'll say the measurement of a .223 case neck with a seated bullet mics as .248". Deduct the bullet diameter (.224") and you have .024". Now that includes both sides of the case neck. Now divide by 2 and the actual neck thickness reading is .012".

Yes, that's exactly what I'm doing, dividing by two etc. I think the issue is the lack of precision in the measurement and as @dellet mentions, spring back. I'm using a .262" mandrel. If I'm out by 0.001", when I'm only looking for 0.002" interfere fit, it makes a big difference.

 

[JEFFPPC]

Good advice given above. A .0001 Mic opens up a whole new world of information. But don't get so wrapped up in numbers you forget the most important information you have which comes from, repeatable targets.

 

[Chubbs]

Done carefully , a blade type will also work. If I'm reading you right, you are seating the bullet, measuring the case, bullet combo and then deducting the diameter of the bullets...are you remembering to divide that result in half since you are measuring both sides of the neck at once in that instance? Not to be rude, but it is very easy to forget that.
Example - We'll say the measurement of a .223 case neck with a seated bullet mics as .248". Deduct the bullet diameter (.224") and you have .024". Now that includes both sides of the case neck. Now divide by 2 and the actual neck thickness reading is .012".

The blade type is not going to tell you if the neck walls are uneven. .024" could easily be .0125" and .0115" and so on. It just all depends on what you want out of your measurements.

 

[BoydAllen]

No I don't, I suspect that's the issue. Which one did you buy?

https://www.amazon.com/dp/B00B5HES1O?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

If you are not familiar with using one, there are some good videos on You Tube.

 

[Tangent]

https://www.amazon.com/dp/B00B5HES1O?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

If you are not familiar with using one, there are some good videos on You Tube.

Thanks, I'll have a look at that. I don't have any engineering background but I'm very aware there is a skill to taking accurate measurements.

 

[bozo699]

Thanks, I'll have a look at that. I don't have any engineering background but I'm very aware there is a skill to taking accurate measurements.

There’s a correct way of holding the mic , since your not use to doing it, it might be worth your time to buy a mic holder , there inexpensive and worth every penny especially with the smaller mic in my opinion.
Wayne

 

[Webster]

When I'm measuring brass I have a hard time getting the measurements to make sense. I measure a seated bullet neck width, diameter of the bullet and calculate the neck wall thickness. That seems to come out at the same or larger than the mandrel diameter. However I can feel the mandrel doing its work so obviously my measurements aren't accurate.

What tools are you all using to do this?

If you turn the necks you know what the wall thickness is. Your making it complicated.

 

[Tangent]

If you turn the necks you know what the wall thickness is. Your making it complicated.

Thanks. I'd rather avoid neck turning as I'm not a BR shooter. It would be useful to know how best to measure anything so I can get an accurate idea of how much next tension I'm applying. However if you want to know how improve your ammunition BR shooters are the people to ask

 

[Webster]

When I'm measuring brass I have a hard time getting the measurements to make sense. I measure a seated bullet neck width, diameter of the bullet and calculate the neck wall thickness. That seems to come out at the same or larger than the mandrel diameter. However I can feel the mandrel doing its work so obviously my measurements aren't accurate.

What tools are you all using to do this?

What do you mean the measurements are not accurate. Whatever you measure the numbers should be real? Without neck turning the neck thickness could vary by 1.5 thou around the diameter.

 

[precision1]

Forster and burst fire sell neck tension gauges also.
They run .001 under bullet diameter to .005 under.
The burst fire is actually pretty cheap also.can get whole set or buy per individual caliber

 

[DShortt]

So.....

Let's suppose you do get an accurate neck wall reading.

What exactly accounts for spring-back in this idea tossed about regarding neck tension?

Is someone here going to tell me there is no difference in the amount of pressure, or neck tension, applied to the projectile, no matter if the case is annealed, fired twice, fired 10 times, let alone the metallic structure/composition of the brass itself? And let's let that round sit for a month, or a year. What was the condition of the neck surface upon seating? Clean? Residue? Powder residue? Bullet surface?

At best, it's an educated SWAG.

You're going to get in the ballpark. But home plate every time?

I have serious doubts.

Just my opinion, and worth exactly what you paid for it.

 

[ELR LVR]

When I'm measuring brass I have a hard time getting the measurements to make sense. I measure a seated bullet neck width, diameter of the bullet and calculate the neck wall thickness. That seems to come out at the same or larger than the mandrel diameter. However I can feel the mandrel doing its work so obviously my measurements aren't accurate.

What tools are you all using to do this?

How are you "calculating"..............neck wall thickness?
You need to use a tubing/(Ball) micrometer for an accurate measurement of this.
Calipers are not the most accurate tool to use for this as the anvils of the face are flat and not round