Caliper case holders?

[Lone Hunter]

If I read your question correctly You are having problems measuring case length and OAL of the bullet. When measuring from base to tip the bullets are going to vary in length especially with the polymer tip. The case, as was said above twist or rotate it to square it up.

 

[cem]

Consider a Redding Instant Indicator. Notice that COAL measured to a datum line will be more consistent than measured to a flexible tip or to a hollow point. Uniform measurements may require uniforming the bullet tip with one of the available tools.

 

[Richard Jones]

I still am not sure that your questions have been answered satisfactorily, so I'll have another go at it and try to summarize:

1. You own and use some sort of headspace comparator.
2. You are having troubles with determining COAL with calipers.
3. You asked if there was a product that would help with determining COAL as you were having difficulty obtaining a measurement due to that slippery bullet tip.

If it were me, I would:
1. Determine base-to-ogive measurement using a stripped bolt.
2. Obtain a comparator for base-to-ogive measurement, or make your own, as I did.
This eliminates having to use COAL at all. Unless you're using a mag, COAL doesn't mean everything. That being said, it's still good to know what your base-to-ogive dimension is.

As discussed previously, practice/experience does come into play here. With either a headspace or base-to-ogive comparator, I do not use any sort of anvil for the base of the case, just the caliper blade. Rotate it, wobble it, etc., until it's square with the blade. Do not use undue pressure. You are looking for the shortest dimension. Make sure your primers are seated below the case head if measuring COAL, and removed if you're just determining your headspace dimension.

I have never seen or heard of anyone on this forum or anywhere else use a micrometer for either headspace or COAL, although it could surely be done.

The Hornady set of base-to-ogive comparators is as good as any for most purposes. There are more expensive/shinier ones on the market, but I believe those will do for most of us mortals.

There ARE some anvils that will attach to your caliper blades in order to be able to insert your case head, but I don't use them, and, as stated previously, they are sometimes misaligned, possibly adding to your stated problem. If you do get them, make sure they are fabricated correctly. Keep in mind that most of them are manufactured "for the masses" and may have the slot wider to accommodate more brands of calipers. This can result in being off center when attached to your caliper blade. That's food for another thread.

I hope this helps. Keep us posted.

 

[williepete]

Is this what you are talking about
Hornaday base anvil and a short actions customs comparator

 

[butchlambert]

Not for reloading but I have used 48" micrometers. Starret makes the best micrometers.

Nettle, Starrett was the cats meow pre 1960s. I only have them to 12".

 

[williepete]

Or is this what you want

Cartridge Overall Length Gauge | Frankford Arsenal

Cartridge Overall Length Gauge

www.frankfordarsenal.com

 

[K22]

I found that the Hornady anvil base as linked to above helps with getting a consistent feel and measurement.

Yea, these can help for sure however make sure the mating surface of the anvil is mill flat.

A friend was having trouble obtaining consistent bump readings with a Hornady tool using this anvil base. We traced it to the anvil being defective, i.e., the mating surface was not flat.

 

[Dr. Jay]

This is a shot in the dark, but google turned up nothing so thought maybe the experts here knew something I didn't.. I'm having a really hard time being consistent with my calipers measuring case length and bullet OAL. Between not always holding the case perfectly straight, and not always perfectly aligning the projectile tip to the caliper arm, I'm finding myself measuring multiple times and coming up with measurements as much as 0.0050 apart.

With my headspace gauge, that measurement is always dead-on, because the cartridge is always consistently held. Is there a simliar "holder" out there that clamps onto caliper arms for empty brass and assembled ammo? Even just something that makes the caliper arms wider, giving me more space to hold the bottom of my cartridge flat against them would do.

I have a set of 0 to2 inch mics and a set of 0 to 3 inch mics that I would sell if that would help you. PM me.

 

[Dave M.]

Is this what you are talking about
Hornaday base anvil and a short actions customs comparatorView attachment 1403230

The Hornady anvil base is often not square is what I found with 4 out of the 7 I checked in my reloading room just now.
Dave

 

[dcali]

Forget about micrometers. That’s not what is needed. You should be able to get repeatable measurements with regular old 6” calipers. Try pressing the base of the case square against the moving jaw and the holding it in place as you slowly close the jaws. Once you contact firmly enough to get a measurement, back off a hair and wiggle the case a little. The idea is to let it “settle” and take out any accidental tilt. As you’re wiggling the he case, put a little more pressure on it until you can hold the case just with the calipers, but no more than that.

With a little practice, you’ll be measuring oals in your sleep.

I have a couple of micrometers. Except for the tube mic to measure neck thickness, I don’t think I’ve ever used them for reloading. Not even once.

 

[Scott-ak]

IMO stop measuring COAL and get a comparator.