I do not think I have mentioned this before.

There is an absolutely perfect way to set your cartridge oal with the ogive just touching the lands.

In this case, the 338 LM. Take a fired case, and drill a 1/4" hole thru the primer pocket. Thread it 1/4x28. DO NOT resize the fired case.

Slip a bullet just into the case mouth, and then thread a 1/4" by 2 1/2" bolt thru the back.

For reasons I will explain at the end, the hex head** is the perfect set up.

As you turn the bolt, it will contact the base of the bullet, and gently begin to move it forward.

Remove the bolt, and slip the round into the chamber. With slight pressure the bullet will move forward into the chamber, and then gently touch the origin of rifling. Stop as soon as you feel it touch.

You have the bolt threaded into the back, so it cannot move either direction.

You now have a place to begin with the seating die. Screw the stem out, and place the round, bolt in place, into the shell holder and run the dummy into the seating die. Run the seating stem down until it gently touches the tip of the bullet.

You are now at zero point.

Set the dummy aside, and work from there; choosing to either jump or jam.

Rich

** the reason to use a headless hex head is so you can make a fixed ogive dummy. The end result is making a semi-permanent tool. Measure the excess length protruding from the base of the case. Unscrew it, and cut that amount off of the front. You should have an exact length for that bullet. Obviously, the only reason to ever unscrew the bolt is to try a very different bullet profile. IE, from spitzer to round nose.

Quite a solution, Rich. I would like to set up my 280 AI handloads to be close to the lands, but did not have a way to measure it. I used an RCBS Precision Mic on my 308, but don't think they make one for the 280. Will have to try this out.

Sounds like a Neco tool.

Stoney Pont system accomplishes this measurement, now owned, soled by Brownells I believe.

quote:

Originally posted by Instructor:
Stoney Pont system accomplishes this measurement, now owned, soled by Brownells I believe.

Your correct. I gave mine away. You won't get a true reading without using one of your own fireformed cases.

OK, how do you insert the cartridge with a screw sticking out of the head into the shell holder?

I do use such a set up, a 10-32 machine screw threaded into the drilled out once fired case- but then I use a comparator & caliper to measure the OAL to the ogive.

I then back out the seater stem far enough to exceed the desired OAL and by trial and error adjust until the round is at the desired OAL to the ogive using the caliper and comparator.

Okay, I reread the whole thing- still- sounds like a lot of effort to make a one-use tool.

I like my adjustable version- no need to insert it into my micrometer seater/die.

For me, it is the measurement that is important- and I have several guns I use it in.

Aside from the Stoney Point system, use a Moe's gauge with .001" increments on the fired case and then apply the appropriate collar on the datum line and read the dial caliper. Using the caliper is not necessary with the Moe's gauge to tell you where to set back the shoulder on the case. Seemingly a lot of folks use a Wilson or Lee case gauge and for me that is merely "eye balling" with no real measurement to rely on. For more precision bolt rifles am careful in resizing brass to match the chamber, but for M14 not so much for those things "eat" brass after some 3-4 loadings, if not less.

Anyone use the Sinclair "bullet depth" checking rod?

Mine has worked well, for me, for many years.

Kevin

Butch is, of course, correct. In a bolt rifle, if there is any play, misalignment, or gap between the boltface and the cartridge upon bolt closure, you are, at best, getting a close guess. That is why fireformed brass must be used in the rifle it was fireformed for.

Of course Butch is correct, but unless you're engaged in benchrest competition the accuracy loss incurred by using the Stoney Point cartridges vs. your own fire formed cases is totally inconsequential. Shooting F-Class long range I wasn't able to notice any difference, and haven't noticed any difference in my varmint rifle.
PS. IIRC Stoney Point was bought out by Hornady, not Nosler.

Yes, Hornady bought Stoney Point.

quote:

Originally posted by swampshooter:
Of course Butch is correct, but unless you're engaged in benchrest competition the accuracy loss incurred by using the Stoney Point cartridges vs. your own fire formed cases is totally inconsequential. Shooting F-Class long range I wasn't able to notice any difference, and haven't noticed any difference in my varmint rifle.
PS. IIRC Stoney Point was bought out by Hornady, not Nosler.

I shot five 1000 yard screamer groups a few years ago using Stoney Pt/Hornady tools to set seating depth. Yes, the gauge is off by the headspace amount, but that is irrelevant. All we need is a reference point and from that we find the best seating depth. Does it really matter if what we thought was .020 off the lands was really .023? Or if what we thought was a .010 jam was .013? My experience says it doesn't.


Having said that, I absolutely agree the way to get a very accurate seating depth is by building your own tool with a fired. However, even with that we'd be off by the amount the brass springs back......

My tool, while primitive by a machinist's standards, works very well, and can be reused for any rifle chambered in the same cartridge.

I used mine, then my gunsmith measured it, and chased the origin of rifling out the difference.
Then, I used dykem red on a loaded round, and got four almost perfectly square marks around the circumference when the origin of rifling began.

I am not there yet, shooting the 1000yd or longer matches, but I did hit a steel plate 12" wide by 18" tall seven times out of the last ten shots at a bit past 1000yds. My fancy Sinclair Competition Rest came today. Who'da thunk the usps delivered on Sundays!

I also got my M5 in the mail yesterday. Precision, 2016-style, is here.

[QUOTE]Originally posted by Kevin Gullette:
Anyone use the Sinclair "bullet depth" checking rod?

Mine has worked well, for me, for many years.

That's what I've been using for about 25 years now and it works like a charm.

I have used the Sinclair version for 20 plus years. I know it, and it works for me.
Doug