Home Forums Reloading Big Game Rifles OACL Question

That wont work if you have fully sized the neck. Too much pressure and you will only jam the bullet into the lands and frustrate yourself.

If you want to try that idea, set up your die so you size only about 1/4 of the neck. Just enough to hold the bullet. If it works out well for you, you will have the distance to the lands.

Put that dummy in your seater die for initial set up, then remove that round and spin the die in about 1/8 of a turn and seat a bullet. Try it in your chamber and if all is good then load up a few at that length.

Do some searching and get some tools: bullet comparator, headspace gauge, etc...

I have the Hornady tool and use it periodically but prefer to use a once fired case from the rifle in question and either slightly size the neck or press the side of the mouth in just enough to grasp the bullet so it doesn't slip. It doesn't take much.
The idea is that the bullet will make contact with the rifling and slide back into the case and stay put without jamming into the lands .003 to .005 thousandths or more and throwing your measurement off or becoming stuck in the rifling.
It sometimes takes a little fussing but once you done it a few times it will become pretty easy.
I would suggest repeating the process a few times and check your measurements to verify a consistent measurement.
IME, a Hornady or Sinclair tool with the correct comparator parts to measure dummy cartridges to the ogive of a seated bullet is an indispensable piece of reloading kit and will give you additional info to produce accurate and safe ammo.
BD

This is a hunting rifle using a full length sizing die. If you shoot and make a reference measurement on an expanded case and then go and RESIZE it to seat the bullet, by very definition you are changing the dimensions you just set as a reference. The bullet is always seated into a resized case so that should also be your reference for measurements. Hornady cases are shoulder sized to unfired dimensions same as the sizing die that will be used.

If you're going to build your own then it should be under the same conditions as the bullet that will actually be seated. But really! it's $6! VERY widely used for decades.

Trimming it is irrelevant unless it is over length, it is the shoulder dimension that is important.

You can fully neck size the case then split it with a small dremel wheel as well.

Shoulder location doesn't mean jack. OAL means the over all length of the cartridge. Think about that for a second. Fancy gadgets are overrated. Just use a piece of once fired brass from that chamber, bump the first .005" of the neck with the sizing die or press the side of the neck up against the corner of a table to allow for slight tension on the bullet, soot the bullet, chamber the dummy round, extract the dummy round and measure the "OAL". Pretty simple really..It's also your perogative if you want to measure to the ogive, but that's not necessary either. I operate by the law of averages and like to keep things simple..

Thats a fact, BSA hit the nail on the head. The distance/measurement from the base of a case in full contact with a closed bolt face to the bullets contact point on the rifling is constant except for continuing throat wear or a change of bullet regardless of how much or little you size a case for ease of loading.
Same thing goes for headspace, that's why Hornady and other makers market comparators and bushings to measure both.
On an aside, I've taken Hornady modified cases and threaded it on to their handle, slid it all the way forward into the chamber and pushed the bullet forward out of the case into contact with rifling and compared the the OAL at the ogive against the fire formed case and gently close the bolt method. There is a difference, in some cases not much, more in others. I've seen variances between .005-.010 thousandths on average, more in others.
This is why I make my own modified cases from fire formed brass fired from my rifle.
BSA's comment about sooting the bullet is spot on, you can also use a black magic marker. The trick to very accurate measurements is to have just enough case tension on the bullet to keep it from slipping back and forth in the neck and not jamming .003-.005 thousandths into the rifling.
It sure as hell isn't rocket science.

BD