O.A.L Question
 

Ok I'm tryin a few different ideas here to get a accurate oal... I loaded a dummy round in a re-sized case and pressed a bullet in it way past were it needs to be. Then I chambered it in my rifle and pulled it out and measured it and got a 2.783 then did it again and got 2.782... My question is would this be a accurate way to get a oal of my bullet touching the rifling???

Watch this excellent video for what you are trying to accomplish:

http://www.ammosmith.com/rifle-reloa...ngth-gauge.php

To the OP:

Not a very good way to get a measurement. Here's why:

1) The lands may be cutting the bullet slightly as you're using them to seat the bullet, so you might actually be "jamming" a couple thousandths. The bearing surface in the neck pressing the bullet into the lands is much greater than the bearing surface of the lands pushing the bullet back into the case, so it's pretty reasonable to expect that you're getting some "jam" when you perform the test this way.

2) Equally, when you jam a bullet, you run the risk of the rifling pulling the bullet slightly as you remove the round. Target shooters often live by the mantra that if a bullet is loaded, it gets fired - that's often because they'll use a minimal neck tension and no crimp, with the bullet jammed into the lands. Open the bolt and you better have the muzzle pointed upward, otherwise you'll be pouring powder in your action or across the bench. And of course, they'll need a range rod to tap the slightly stuck bullet out of the lands.

3) There are time proven methods for determining COAL, and there are even "modern" methods for using expensive tools to measure it. No reason to use a less than ideal test method.

I'd be interested to see what happens - crimp the bullets at that COAL, then mark the ogive with a magic marker and run them through the rifle. I'd venture there will be a bit of a "kiss" in the magic marker line from the lands.

Did you watch the entire video and listen to what the guy said or is your post directed to the OP himself the way he's doing it?

The video is describing the same process as the OP, and regardless of what some guy puts up on his blog - I do not believe that this process is a sound reloading technique.

All of my concerns listed in my first response stand true for the video as well.

You've watched the video - he references a 10thou jump, AND he references that he can see that his bullet has markings from the lands. Take a look at the edge of a 5 thou feeler gauge, hold it up against the ogive of a bullet some time - that'll give you a feel (pun intended) for how long a witness mark has to be on a bullet to be visible to your eye. So if he has a 10thou intended jump, but a 3thou witness mark left on his bullet, he's really only jumping 7thou. If he uses the same case (as he did in the video) to repeat the test, and he's pushed 1thou less neck tension by resizing the brass or bullet ever so slightly, maybe the next measurement will show 2thou less witness mark. Or maybe it'll hang on the lands just a tiny bit and pull back 2thou...

Or say next week, you do it again with a different bullet and you size a different case that doesn't have the same neck tension, and it might produce an entirely different result. If the new neck has been work hardened a bit more than the other, it might resist slip a bit more than the first case and push a bit more "kiss" onto the bullet - call it 2thou, so then you're looking at 2thou longer COAL measured on that day.

And for what it's worth - COAL really isn't that important anyway. I'd rather have a batch of ammo with 1thou or less variance in ogive-to-base length and COAL's all over the map instead of have a bunch of ammo with perfect COAL's and variable tip damages that put my ogive position and bullet jump all over the map.