Measure C.O.A.L. from Tip or Ogive?

[PTLaro]

It appears that loading manuals measurement C.O.A.L. from the tip. However the only reason I see for this is so the cartridge will fit in a magazine. Yes that is important.

However, it seems that it should be measured from the ogive when it comes to when the cartridge is in the chamber. That would help with headspace and accuracy?

I know every chamber and bullets are different but measuring from the ogive seems more accurate and helpful.

What is the point of measuring from the cartridge tip?

[JagerDog]

Well...there's no SAAMI spec for where the ogive is.

You're correct that how far off the lands (ogive it what touches) is often a consideration when loading for precision rifle and that will be individual to the rifle.

[LynnJr]

The only reason to measure to the tip is for magazine feeding.
The ogive is very consistent and you want to measure as close to the bores diameter as possible because that is what touches the bullets bearing surface.
Once you know the length it will be the same length no matter which bullet shape you choose.
If you measure from the tip it will change with every bullet type you use.

[micro911]

For a precision loading, I use ogive length. It is more consistent than measuring to the tip.

[TomReloaded]

With FMJ bullets, the variance bullet to bullet is smaller than the variance I get naturally from my press. I can do them one by one and shrink that variance inherent in the press, but I dont shoot far enough for that to actually help. It just takes a ton of time.

[JagerDog]

You seating die registers essentially on the ogive. eg your seating die is more consistent in relation to ogive than your calipers measuring COAL.

[bigdawg86]

Once you know the length it will be the same length no matter which bullet shape you choose.

Is this reliable practically speaking? It makes perfect sense but, I have used flat base bullets and VLD bullets and if I recall correctly my measurements were not universal between the two. I am using the Hornady OAL gauge.

[8mmFMJ]

You seating die registers essentially on the ogive. eg your seating die is more consistent in relation to ogive than your calipers measuring COAL.

This. I always get it close, tighten, and then press em all. I don't measure each finished bullet that would drive me crazy. The variances in projectiles can leave you thousandths apart on OAL without you touching the die. The OGIVE is always the same though.

[PTLaro]

Thanks for respones

[LynnJr]

Your seating stem doesn't seat the bullets off of the ogive unless it has the round sleeve inside of it and most don't.