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

D

Duncan74

Inactive
I've been reloading for 7-8 years now. I know someone is laughing at me right now but what is the proper term for this measurement?

In my notes for my own personal info so I know what measurement it is I simply have been writing down B.S. O.A.L. for Bullet Shoulder(ogive) OAL.

But I know there must be a proper term for this measurement. What is it?

Thanks. Sorry for the dumb question.
 
Never a dumb question. When sizing the case, the distance from the shoulder or datum line to base of the case is headspace, its letting you know how much room is left between the head of the case & the bolt face. Over All Length, is the measurement from the head of the case to the tip of the bullet. Not the most accurate measurement but when loading into a magazine or chamber, its standard for the firearm to operate. Ogive measurement let's you know the amount or space to the rifling. Hope I helped.
 
Maybe there is no proper term, in which case we can invent one.

I suggest calling it the Duncan measurement after the one who posed the question.
 
If any thought had ever been put into a term to describe the distance from the rifling to the bolt face the information would be available from Sinclair and or Hornady. I make tools that allows me to transfer the measurement to a seating die, I call the tool a transfer; I know that is not very catchy but once I know the distance from the rifling to the bolt face I am not required to start over the next day.

We can talk about the tools that are made for measuring the distance from the beginning of the rifling to the bolt face. Most of the tools are made to be bullet friendly meaning the tools have radiuses instead of sharp edges. My tools imprint on the bullet.

F. Guffey
 
I saw in a publication stated as "Cartidge base to ogive" or "C.B.T.O." I've always used that to descibe it.
 
BTO sounds pretty good to me.
Click to expand...

If any thought had ever been put into a term to describe the distance from the rifling to the bolt face the information would be available from Sinclair and or Hornady.
Click to expand...

BTO is the measurement made by the Sinclair/Hornady tool because the ogive is on the bullet.

F. Guffey
 
I list both the case and chamber because that is what SAAMI does. Then there are reloaders that speak where SAAMI is silent. SAAMI does not identify head space for the case but reloaders managed to purchased case head space gages even thought 60 + years ago L.E. Wilson started selling case length gages complete with instructions dated 1954.

F. Guffey
 
Well, I ain't laughing! I started reloading in 1969 and I can't answer your question. I've done it a few times, and used the Hornady tools designed for the job, but I don't have a clue of the correct term...:o
 
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.
 
Never liked using initials instead on of words. BTO, BTR or BTU's. Sorry, that one is National Security.
 
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.
Click to expand...

Actually? I am the fan of transfers and standards.

F. Guffey
 
What SAAMI does not use is the ogive for any measurement. OAL is measured from the pointy bit to the flat bit of the cartridge.
The ogive is on a different part of nearly every bullet type with the same weight. Look at the .224" 55 grain bullets from Sierra.
https://www.sierrabullets.com/products/bullets/rifle.cfm
"...C.B.T.O. at .177 diam..." Is at least a standard. Isn't used by anybody, but it's a standard.
"...SAAMI does not identify head space for the case..." That's because headspace is a rifle manufacturing tolerance only. Cartridges do not have headspace.
"...60 + years ago..." 62. Last March. snicker.
 
Well this turned into a good thread. Someone was explaining all the measurements. I appriciate the time you took to do that but I completely understand all the measurements and how they are taken and I have all the tools to take the measurements.

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.

Then when I start working up loads for a gun I will then step back and load 5 shells to test at each length off the lands in .005" increments. .005", .010", .015", .020", and .025" to find out if the gun likes the bullet close to the lands or more bullet jump. Although a lot of bolt action rifles with a lot of throat wear the max OAL won't actually be the real max OAL because the cartridge won't fit in the magazine because the actual OAL is to long. So sometimes my max C.B.T.O. for certain rifles is simply the max length that the magazine will function with.

I was just curious if there was a proper term for this measurement from the back of the case to the bullets Ogive. As I said I personally for my own notes write these measurements down as B.S.O.A.L. For what I call the Bullet Shoulder(ogive) O.A.L.

I was just curious if there was a actual universal term for this measurement so that when discussing bullet seating lengths on this forum with everyone; people would know what I was talking about. I assumed or thought for sure their would be a definite term for this. It sounds like maybe the actual term is C.B.T.O for Cartridge Base To Ogive?!?

Thanks fellas. Good discussion!
 
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