What is the proper term for measuring from the bullet ogive?

SAAMI gives maximum and minimum measurements for case manufacture. That is all chamber specs do. I consider headspace the matching of the two. Without the standardization of the cartridge case, chamber headspace would be meaningless. The chamber specs actually dictate where the ammunition manufacturers place the ogive of the bullet. Some may fall way short of the rifling, but no loaded SAAMI spec ammo will exceed that point. You will just have a lot of "Freebore".
 
Duncan74
Looks like no one really answered the question. I guess what ever works for you to reference your notes is best. For me when I read just the initials, its like trying to figure whats on car vanity plates. I just wright the whole thing out. If it doesn't rain in the morning, I'll be trying some jump rounds. Be Safe. Chris
 
What is the proper term for measuring from the bullet ogive?
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From the bullet ogive TO WHERE????

Ogive is the curve of the bullet's forward portion. Hornady defines both a tangent and a secant ogive.

Your question is unclear to me, exactly what you are measuring, from where to where??
 
C.B.T.O for Cartridge Base To Ogive?!?
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The bullet has an ogive, somewhere along the ogive the bullet contacts the rifling meaning the chamber does not have an ogive.

I use the Hornady bullet comparator that goes on your calipers to take this measurement and the Hornady headspace comparator to check my head space. I use the Hornady OAL gauge to find my max OAL length and use the bullet comparator to take the measurement.
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Back to calling everything a head space tool and everything having head space. The Hornady tool is a comparator, if you measure before and again after you have just about mastered the comparator. The case does not have head space. Back to the Wilson case gage, it is a datum based tool, the complicated part about the Wilson case gage with a datum is the way they ZEROED the tool; Hornady has never caught on to that concept, the same goes for reloaders.

You are missing a measurement; I am the fan of transfers, I transfer the measurement from the chamber to the seating die. I know that makes no sense to anyone but I do not need the Hornady tool nor do I need to measure the length of the case from the rifling contact point on the bullet to the bolt face.

F. Guffey
 
The case has the chamber's specs as a dimension guide line. You could load a few of the wrong cartridges in a rimmed chamber and still pass the chamber headspace specs. The chamber DOES have a dimension to agree with the ogive on a bullet and bullet diameter. That little angle you grind on forward of the freebore varies with different cartridges. I suspect the angle helps the bullet stay concentric with the barrel because it agrees with the curve of the ogive.
 
Would anyone knowingly use a 17 caliber tool to measure a 30 caliber
round?:confused:

Reason for my post;
Actually base to ogive would be a comparative measurement dependent on the diameter of the measuring tool, i.e. The measuring tool diam. would have to be included in the specs.

Example: C.B.T.O. at .177 diam.
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Some of yalls comments are like outter space talk. Some of the comments have nothing to do with my question that I asked.

This thread is completely off subject now.
 
I use a comparator to take that measurement and refer to it in my notes as my comp measurement . I do how ever like the CBTO or even better BTO

Many , MANY guys use the term case/cartridge head space which distinguishes it from head space which is a chamber measurement .
 
I just simply call it "Ogive Measurement". Nothing fancy for me, I know what it means and how I came about such a measurement.

Some of you folks get way, way, way, way too wrapped up in simple semantics....
 
This answer your question,mikld, the .177 I gave was purely a hypothetical for illustration. My tool for measuring .30 cal is .296 diam. I believe.

My reasoning is that I want the measuring tool diam close to bore diam of the rifle so, say, .010 of meas. to ogive translates to .010 adjustment of my seating die. Or close,anyway.
 
CBTO

I like this abbreviation much better than what I was using in my notes. This is what I have decided to start using in my notes. Thanks.
 
This answer your question,mikld, the .177 I gave was purely a hypothetical for illustration. My tool for measuring .30 cal is .296 diam. I believe.
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If your .30 caliber is .296 it is too small in diameter, my 30 caliber barrels have two diameters one is supposed to be .300" and the other .308". Meaning the bullet will imprint on the rifling between the two diameters and then there is the bullet friendly bevel.

So when using a transfer I imprint the bullet, I know that makes them ugly but once I determine the beginning of the rifling I do not have to start over the next day.

F. Guffey
 
You misinterpreted his post. He's referring to his tool dimension, not his barrel dimension.
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This answer your question,mikld, the .177 I gave was purely a hypothetical for illustration. My tool for measuring .30 cal is .296 diam. I believe.
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There is no way to misinterprete if he finishes with "I believe" and I start with:

If your .30 caliber is .296 it is too small in diameter
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He believes means he does not know and if I start with if means if the diameter is .296" he could drop his tool thorough the barrel.

F. Guffey
 
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