Overall Case Length

[Hunter]

Using standard RCBS seating dies and a run-of-the-mill digital caliper, I get inconsistent OAL measurements on my reloads (measuring from cartridge base to the tip of the bullet). I don't know if the problem is in the seating die, the caliper, or the actual bullets. I measured some 69 grain, .224 Sierra Match bullets (bullet-base-to-tip) and got inconsistent readings on the actual bullets -- as much as .005+. If the problem is in the bullets, I wonder if the bullet-base-to-ogive measurements are also inconsistent. Thoughts?

Another question for those of you who use a comparator, do you notice any wobble between the comparator and the bullet that would give inconsistent readings? Which comparator do y'all use -- the nut or the insert-type?

 

[HovisKM]

What you are seeing is very common and is why a comparator is used. I use the nut type and have been very happy.

Hovis

 

[zippy06]

Aka. All the above.
Everything moves. Lead core moves, jacket moves, brass moves, etc.
Everything is made just a little different. Different temp, diff. make up of material, diff. measurements, etc.
What you measure with a 1" mic. Will be different than what I measure with a 1" mic.
6" calipers are the worst.
Every time you shoot your rifle. All conditions will be different. Why worry about some measurements.

"The Old Guy" says.
Buy the best equipment, you can buy. Or you are paying for it twice.
And he says "Just shoot em' ".
The Old Guy has more HOF points then I do.......

 

[Hunter]

Why worry about some measurements.

"The Old Guy" says.
Buy the best equipment, you can buy. Or you are paying for it twice.
And he says "Just shoot em' ".
The Old Guy has more HOF points then I do.......

I'm puzzled over which measurements to worry about -- Exactness of powder charge? OAL? Consistency of brass weight? Consistency of bullet weight? Concentricity of the neck? I'm sure there are others. Basically, I like the second part of "The Old Guy's" advice -- I just keep getting beat by guys who talk about doing all the measuring.

 

[lefty o]

your die seats the bullet at the ogive, therefore most likely that dimension cartridge base to ogive is most likely spot on. measuring from cartridge base to bullet tip is giving you varying lengths because of the bullets are inconsistent.

 

[alinwa]

I'm puzzled over which measurements to worry about -- Exactness of powder charge? OAL? Consistency of brass weight? Consistency of bullet weight? Concentricity of the neck? I'm sure there are others. Basically, I like the second part of "The Old Guy's" advice -- I just keep getting beat by guys who talk about doing all the measuring.

Measuring is good, you must know how to measure and to gauge for the purpose of assessing your system but there's a lot to learn about measuring In your case the measurement you're taking is meaningless. As Hovis has stated, you must measure from a consistent point.... NOT the point of the bullet (pun intended)

Bullet TIPS vary a lot.

al