Sort of a newbee here but I think I should be able to hold an exact COAL from one round to the next yet I am getting up to.003 variances,any help would be appreciated.

If you are measuring from the base of the cartridge to the tip of the bullet that`s about as good as it gets. You need a bullet comparator and should measure from the base to the ogive of the bullet to get a reliable reading. Sinclair, Hornady, Stoney Point all make them at a reasonable cost.

Thanks ole Joe, I guess your right I am measuring from tip to tip.

Often if you are measuring the lengths of soft tip bullets of the same type and lot you would get a variance of that much. I've measured hairs that are > .003". No!!; not a RCH. roger

Use a comparator as suggested and also a competition bullet seater. Seat them out about 0.005" longer than you want then "tweak" each one individually. That's how I do it but I'm probably too anal about it. You'll find some differences in almost each one. Probably doesn't matter to get that close.
Bear in Fairbanks

Your bullet seating plug contacts on the ogive, not the tip of the bullet. It is not flat, it is a cup shape.

The length of the tips of the bullet will vary several .001s, even W/polymer tipped bullets such as Nosler Ballistic Tips.

The COAL @ the tip is moot anyway as long as the COAL will still funtion through the magazine.

Don't sweat it, the length @ the ogive is what maters anyway. You can get a "comparator" if you like, but I think you will find that the length @ the ogive IS consistant anyway.

I use 1 dedicated dummy round to set COAL so that the ogive is just off the lands. I do not use any fancy tool for that either.

1st, establish the distance to the bolt face by inserting a ramrod W/a flat tipped jag into the bore until it meets the bolt face when the striker is cocked. Place a colar on the rod where it meets the muzzle & secure it W/a set screw.

Then, just push the bullet you want to use in your dedicated dummy round into the chamber until it contacts the rifling. You can bo this W/a dowel rod. Hold it firmly against the rifling (a fairly stiff spring W/a closed bolt would work for this) while you place a ramrod W/the colar into the bore until it contacts the tip of the bullet. Now measure the distance from the muzzle to the colar. Deduct the amount that you want the bullet off the lands & you now have your COAL.

USE THE EXACT SAME BULLET FOR YOUR DEDICATED DUMMY ROUND.

You can now use that dedicated dummy round for setting your bullet seating die.

The only measuring tool you need for this is a dial caliper.

Don't even bother trying to hold it to the thou. You can't do it; even match bullets aren't that uniform. Load to the hundredth and be happy.

quote:

Originally posted by Ol` Joe:
...You need a bullet comparator and should measure from the base to the ogive of the bullet to get a reliable reading. ...

Hey Curt, Welcome Aboard!

If you have a Tool Box, you can use a "socket" from it and accomplish the same thing - at no additional cost for a Thingy. Just use the Largest Scoket - which will not slip past the Ogive - and you can measure the Ogive to Bullet Base or the Ogive to CaseHead distance as you desire.

I'd also recommend you try the OCL-to-ODL Seating Method as you move forward. It allows you to Seat the Bullet any distance Off of or Into the Lands you desire easily and quickly, without a lot of Trial and Error attempts.
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You will find a Variance on all Bullets from Tip to Base. Some are better than others and some Lots of the same exact Bullet often vary a good bit. Once you determine the best Seating Depth, as long as you have the Ogive off the Lands that same amount, normally all the Bullets within a Box will group the same - if your firearm likes them to start with.

Best of luck to you.