OAL varies from round to round

[steeps09]

Im reloading a 155gr LRN over Bullseye powder for my 4th Gen G22 on a Lee Pro 1000. The maximum OAL is listed as 1.130in. Advise from manuals and several veteran reloaders I know, my seating depth is about 1.124in. Now my situation is that the OAL on my finished rounds will vary from 1.121-1.130. Now, is this something that I should worry about or not? I have double checked the dye and it does not appear to have moved, so I do not know why this is varrying so much. I know that each bullet and case is different so there will be a variance from round to round but I didnt know it would be this much. Since I am reloading .40's my room for error is small and I dont want a KABOOM.

[NWPilgrim]

I don't think that is much variance as far as the pressure goes (0.006"). But normally it should not vary that much.

I common problem with lead bullets is that the lube gums up the dies and then falls out in chunks and falls out in chunks again. Such buildup can cause that much variance.

Often this buildup of lube is exacerbated by trying to crimp in the same die as you are seating the bullet. You are then trying to push the bullet down in the case at the same time as the case neck is being squeezed tighter.

This is the reason I have switched to crimping in a separate die after the bullet seating. I get much more consistent bullet seating and easy, less messy crimping. You can buy a separate crimp die for $10.

[Lost Sheep]

Originally Posted by NWPilgrim

I don't think that is much variance as far as the pressure goes (0.006"). But normally it should not vary that much.

I common problem with lead bullets is that the lube gums up the dies and then falls out in chunks and falls out in chunks again. Such buildup can cause that much variance.

Often this buildup of lube is exacerbated by trying to crimp in the same die as you are seating the bullet. You are then trying to push the bullet down in the case at the same time as the case neck is being squeezed tighter.

This is the reason I have switched to crimping in a separate die after the bullet seating. I get much more consistent bullet seating and easy, less messy crimping. You can buy a separate crimp die for $10.

NWPilgrim, you are correct about the seating depth variation being small and probably not dangerous but greater than acceptable.

I am inclined to ask if Steeps09 is making a full stroke on every round. If a round being sized requires more force than normal, the round being seated might be getting a short stroke. On the other hand, if the round being seated requires more force than normal the shell holder plate or the die turret might be tilting and giving the bullet being seated an extra-deep seating.

The press, shell plate or turret head should not flex that much. but I suppose it is possible.

One way to test this theory is to run only one round at a time in the press for a bunch or cartridges and see if the OALs get more uniform.


The original post did not specify if lead rounds with the type of lubricant that gums up dies in chunks like that described. Jacketed or plated rounds should not be subject to the problem of lube building up on the bullet seating die and changing the seating depth.

Separating the bullet seating die from the crimping die is a good idea, but not easily done in the Pro-1000, which has only three die stations.

Good luck, Steps09. Keep the good ideas coming NWPilgrim.

Lost Sheep

[MW surveyor]

I recently had a similar problem loading 125 gr RNL for my 9 mm only with a much greater spread than yours. After much head scratching, I decided to check the length and weight of a number of bullets. The weights were within 0.5 grains of each other. From my measurments of the non-loaded bullets remaining in the box, had lenghts varying from 0.595 to 0.612. Then looked at the shorter and longer bullets real carefully. You could see a big difference in the taper of the ogive. The longer had a much "slimmer" ogive than the shorter and thus contacted the bullet seater at a different location. Seems like the caster was using different molds with enough difference in the bullet design to make a large difference in where the bullets were seated.

I finally gave up, took the bullets back and have since ordered from a more reputable caster with better quality control.

[Uncle Buck]

Two things come to mind.

Your seating stroke and lube.

It does not take to much extra lube for it to build up in the die. The die acts sort of like a squeegee (?) and wipes a little off each time. You may have to clean the die much more frequently. You can not compress a liquid.

Is your stroke the same with every round? Eyeball your stroke and make sure you are getting the full stroke. Re-adjust your dies if you are not.

I do not see how bullet length would cause the problem if you are using the same stroke. Because at the top of your stroke (Or the top of the ram), you have compressed the space between the die and the shell holder the same amount of space each time, if you are doing consistent strokes.

[wncchester]

"is this something that I should worry about or not? "

Not.

[gregjc9]

Something else to check - depending on how you take your OAL measurements - the primer might not be seated quite as deep as it should be. I ran into this recently on my LNL (still learning the press), and it took some head-scratching before I figured out my Winchester primers werent being seated quite all the way, just enough to give me varying OAL lengths.

[engineermike]

Steeps09;
I am just curious as to what press/dies you are using? I am using a Hornady L-N-L Classic single stage press and the Hornady dies and I too get various C.O.L.
I don't really worry about it but I on the seater/crimp die there is a soft washer and I am wondering if that might be the cause of some of my various length. As I said just curious.

Mike

[k4swb]

I had this problem with the Hornady seater. Removed the rubber washer and the problem went away.