Best way to measure inside neck dimension

[Bang4theBuck]

Good Morning. I am a long time reloader, but have never taken the time to come up with a way to measure the inside diameter of my case necks. I have over the years purchased various tools like a ball-end micrometer to accurately measure the case neck thickness and such, but all methods arrive at a dimension by taking multiple dimensions and doing math (i.e. neck thickness x 2 minus the outside diameter of the case neck). Not that I can't do math, but looing for a simple accurate means to measure inside neck dimension. I am not opposed to buying a measuring device, if that is the answer, but what type of device would it be.

Please advise.

Thanks

 

[Barrelnut]

Check these Forster neck tension gages out. They just came out this year. I would like to have a set.

 

[parshal]

Watched the above video. That's a nice set of tools. But, you can get gauge pins in the size you want much cheaper and even in .0005" increments. You can buy them individually or a whole kit on Amazon.

 

[Pdyson]

a machinist pin guage set works but it's hard to find a kit that will cover .22 through 308"

 

[Taylorbok]

Is there a reason you care to measure ID? From my knowledge and experience it doesn't overly matter as long as it is consistent. Obviously with in reason, it has to provide enough tension to hold the bullet but large enough to allow seating of projectile.

 

[Petey308]

Is there a reason you care to measure ID? From my knowledge and experience it doesn't overly matter as long as it is consistent. Obviously with in reason, it has to provide enough tension to hold the bullet but large enough to allow seating of projectile.

Agreed. Consistency is key and as long as the tension is uniform throughout the neck and in contact with the bullet, and as long as it's sufficient to hold the bullet from moving under recoil, it doesn't really matter what the ID is and to try to chase a certain dimension.

I just properly anneal every firing, size the brass and use a mandrel to set my final neck size and I'm good. I know it's a sufficient amount and is consistent and uniform.

To answer the OP though, I agree with using gauge pins for the most cost effective method.

 

[parshal]

They are useful for determining the amount of springback. More importantly, though, you can easily confirm presence of a donut.

 

[Bang4theBuck]

To answer the questions on why I care about inside diameter.....Well, my experience is that control of neck tension is a significant accuracy contributor, as well as a velocity control contributor. I have evolved into not doing any part of my reloading blindly, or with reduced attention to anything, dimensionally. To me, reloading is all about cause and effect, and if I take good notes and take good dimensions, I can often find problems in the details that are keeping me from achieving my goals.

It sounds like pin gauges are the way to go. I made a set of go/no gauges for primer pockets out of pin gauges, and never even thought about using them for this...makes total sense. Thanks.

 

[338 dude]

Good Morning. I am a long time reloader, but have never taken the time to come up with a way to measure the inside diameter of my case necks. I have over the years purchased various tools like a ball-end micrometer to accurately measure the case neck thickness and such, but all methods arrive at a dimension by taking multiple dimensions and doing math (i.e. neck thickness x 2 minus the outside diameter of the case neck). Not that I can't do math, but looing for a simple accurate means to measure inside neck dimension. I am not opposed to buying a measuring device, if that is the answer, but what type of device would it be.

Please advise.

Thanks

 

[Mikecr]

I have evolved into not doing any part of my reloading blindly, or with reduced attention to anything, dimensionally.

You're not blind, but you are lost.
Tension is not an interference dimension. Tension is a force. It's measure would be expressed in pounds per square inch (PSI).
So measuring neck IDs will not provide tension information.
Waste of time

 

[Bang4theBuck]

I've gotten what I need from previous posts. Thanks to those with suggestions.

 

[Taylorbok]

You're not blind, but you are lost.
Tension is not an interference dimension. Tension is a force. It's measure would be expressed in pounds per square inch (PSI).
So measuring neck IDs will not provide tension information.
Waste of time

I mean this could all be measured but you can assume a consistent neck thickness with a consistent ID will produce the same neck tension. He isn't actually trying to find the force exerted on the projectile he is still just aiming for consistency.

 

[newmexkid]

If I heard correctly the video dude said the case he measured was in between .262 and .263. Well, I can get that close with my calipers!

 

[JuddL]

Use a micrometer, measure total diameter of the neck…then subtract both sides thickness of the brass neck. That will give you inside diameter and likely not need to buy any additional tools.

Pin gauges are the answer but not cheap and you need a bunch of them.