seating depth inconsistency

[dakota954]

when i go to seat the bullet, i get it set to a specific depth then i try another cartridge using the same bullet, brass, primer, powder, everything the same and the depth will be different. not by much, but it will vary by .005 of an inch. this happens with every caliber and die i try it with. i either blame myself or my bench. what i do is: screw the die in, make sure its nice and tight, put a round in to set the die, push the lever all the way down then back off and check the depth. then, try again and the depth will be different.it gets deeper and farther so the die isnt backing off. i think that it is my bench as its not very sturdy and when i push the lever all the way down, the bench creeks and bends a little bit. i plan to bolt it to the floor and put a thicker piece of wood under the part where the press sits to stop the bending. any other info of what could be wrong would be greatly obliged

[Win 1917]

The points on bullets often aren't that consistent and could easily account for your varying COAL from round to round.  

How you're getting different depths when setting up the die I don't know exactly. If subsequent bullets seat to the same depth as when you run the bullet in the second time then I wouldn't worry about it. When you screw the seater stem down onto an existing round to reset the seating depth that isn't an exact process. It gets you very close but I find it takes another little tweak or two to get the seating depth back exactly to where it was with the template round. There's probably a little slop in the threads. The pressure on the bullet from the stem being screwed down isn't quite the same as when the bullet bumps into the seater when your raising the ram etc.    

[R.W.Dale]

What you're seeing is bullet to bullet variances particularly the tip.  

Look at your bullet seater. You'll note it does not seat from the bullet tip but rather a point just behind. Now measure several bullets and note how especally with SP's the tips vary.

This is what you're seeing.  If you buy and use a bullet comparator your measurments will be much more precise as you'll be measuring from the start of the bullets bearing surface and not thr inconsistent tips.

And of course when you get right down to it .004" isn't very darn much.

[Win 1917]

If you buy and use a bullet comparator your measurments will be much more precise as you'll be measuring from the start of the bullets bearing surface and not thr inconsistent tips.

And of course when you get right down to it .004" isn't very darn much.

+1

[diddlyv]

If you are really concerned you can get a case mic to check the seating depth.  These things have a hole the bullet goes thru and measure a at a specific diameter on the bullet ogive.   For any specific bullet they will let you know how consistent you are.  I was going nuts trying to get sierra match kings to be the same length measured with a caliper.  Called sierra and they told me the tips were all different so the COLs would all be different but the case m

[wncchester]

"i either blame myself ...."

Well, you share it with the normal variations in bullets.    Varitations in how we operate the press will also add a few thou.
Happily, such tiny differences are meaningless, the rifle couldn't care less where the nose of a bullet hangs in space.

[buck460XVR]

You don't say whether you are loading lead or jacketed bullets. Are you loading handgun bullets and seating and crimping in the same step? Does your seating die match the profile of the bullets being used? Regardless of how flimsy your bench is, the press itself would have to have play/flex in it in order to create the inconsistency, if there is not some other reason.

[Catfish]

I would guess that Win. 1917 has probly hit the nail on the head. If they shoot well don`t worry about.

[cybin]

If you are loading lead cast bullets I have run into this problem myself. A built up of bullet lube inside the seating die that plays with the OAL. I just clean the seating die every so often in a parts washer. I have has this problem pop up only with pistol calibers though--mostly .357 and .38 special, and .41 mag, but then I don't load cast bullets in my rifles.

cybin