problems with LEE seating die


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xd9
November 2, 2009, 12:35 AM
Hey guys I just loaded my first 10 rounds and I am having problems with the consitency with the seating die. I am trying to get a depth set at 1.120 and I can get one set at 1.120.5 but the next round I seat seems to seat at around 1.114-1.116 I was wondering what would cause that and if any one had the same problem.

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R.W.Dale
November 2, 2009, 12:57 AM
what bullets and cartridge are you loading for?

.006" is not unheard of for bullet length variations. Remember bullets seater contacts the bullet partway down the Ogive and not on the tip. I'll wager that if you used a bullet comparator your seating depth would measure out much much more consistently.

Or to put it simply it's not the bullet seating that varies but the bullets themselves. Any seating dis can only be as consistent as the bullets you're using

Lee Roder
November 2, 2009, 01:23 AM
What are you loading? If handgun, then your seater most definitely pushes straight down on the "tip", at least with flat wadcutter-like points

Maybe you are beginning to accumulate "crud" in the die, things like bullet lube, ...?

R.W.Dale
November 2, 2009, 01:33 AM
What are you loading? If handgun, then your seater most definitely pushes straight down on the "tip", at least with flat wadcutter-like points

Maybe you are beginning to accumulate "crud" in the die, things like bullet lube, ...?



It depends on the seater and bullet. For example I have 3 seaters with my 38spcl dies and only the wadcuttet seater plug would contact the bullet nose squarely. The HP and RN seaters both seat off a point partway down the bullets ogive

Lee Roder
November 2, 2009, 01:40 AM
well, i just took a lead RN bullet i pulled (i odn't load them), and took a round nose seater out of an rcbs die and pushed and twisted it onto the bullet's "ogive" to see where it set. the only mark the seater made was at the very tip of my bullet. perhaps my bullet was improperly shaped, it's from serbia. :neener:

Otto
November 2, 2009, 01:56 AM
Tolerances of .006" ain't nothing to lose sleep over. I've seen much more variance in WWB 9mm. Even my Redding competition seating die varies by a few thousandths.

jcwit
November 2, 2009, 06:09 AM
Nothing to get worked up about. A std sheet of Magazine paper is .003 thick, you're talking about 2 pieces of paper.

243winxb
November 2, 2009, 08:07 AM
.005" to .010" is common. There are a number of possible causes for overall length variation. One is the way it is measured. If you measure overall length from the tip of the bullet to the base of the case, remember to subtract the variation due to bullet length tolerance. The bullets will vary in length due to manufacturing tolerances (bullets with exposed lead noses are the worst in this regard) and this will add to the overall cartridge length variation. Remember that the bullet seater plug does not (or shouldn't) contact the tip of the bullet when seating, but contacts farther down the ogive. For a more accurate seating depth measurement, take the seater plug out of the bullet seating die, place it on top of the cartridge and measure from the base of the case to the top of the seater plug.

Another possible cause for bullet seating depth variation is seating and crimping at the same time when trying to apply a firm crimp to untrimmed cases. Variation in case length also causes variation in the amount of crimp applied. Long cases get a heavier crimp than short ones. When seating and crimping at the same time, the crimp is formed as the bullet is seated into the case. The crimp will form sooner on a long case, and therefore the bullet will not be seated as deeply. The solution is to seat and crimp in a separate step (the Lee Factory Crimp die is good for this) and/or trim cases to a uniform length.

The amount of force required to cycle a progressive press varies with the number of cases in the shell plate. When the shell plate is full, it is harder to lower the lever than when there are one or two cases present. This can lead to variation in cartridge overall length because there are different loads placed on the working parts of the press. When the shell plate is full, seating depth will be slightly long, because the load is higher and all of the clearances are taken up. With the shell plate nearly empty, the load is not great enough to squeeze out these clearances, and the seating depth is short.
http://www.leeprecision.com/cgi/faq/index.cgi

Walkalong
November 2, 2009, 08:55 AM
Some of it just depends on the bullet and its fit to the seater plug. I would not be happy about that big a difference, but some combinations will do that. Is everything tight and clean? If it shoots good though, I wouldn't worry to much about it.

rfwobbly
November 2, 2009, 09:14 AM
I agree .006" is nothing. It could be....

• Seating the bullet by pushing on the sides rather than the tip
• Bullet lube built up inside the die
• Differing press handle techniques
• A progressive press that uses a single die holder will rock the holder if all cartridge positions are not being used

What really matters is the variation over an entire run. That is, the difference between the longest and shortest loaded cartridge after making 50 or more rounds. That's the number to remember.

ranger335v
November 2, 2009, 09:41 AM
Seating variations come from inconsistant press operation, widely varing case mouth thickness or misadjusted crimping, not a die.

xd9
November 2, 2009, 12:07 PM
Hey sorry I havent answered any questions yet. I am loading 9mm and this is the first time I have used this die, the reason I am worried is becaise I read somewhere that if you seat the bullet lower it causes a huge diffrence in the pressure in the case which could damage the gun. Also I am using magnum primers because they are the only ones I could get my hands on, and I am using blue dot powder which most people dont seem to like just a little nervous is all. thanks for all of youre guys help.

Walkalong
November 2, 2009, 12:17 PM
In previous threads folks with the Lee dies have tightened up the O.A.L. differences by just getting everything snugged up. That O Ring will flex differently from round to round depending on neck tension differences if the die is not snugged down well.

.005 is not going to make anything go boom on any reasonble load. Speers caution in their manual talks about a much bigger difference. .030 or .060 IIRC.

helg
November 2, 2009, 12:44 PM
Blue dot is slow (and safe) powder for 9mm. Even if you fill the powder to 120% of the volume under bullet (it is named 20% compressed charge), and seat the bullet to make OAL by .1" (not .006" like you said, but full .1") shorter than the max, chamber pressure is still about 60% of the maximum allowed for the caliber.

Noveldoc
November 2, 2009, 12:52 PM
Some could be technique. There is a certain kind of crunchy feel with my Lee dies when the bullet is seated all the way home. Just takes a little practice and muscle memory to find and keep this setting.

Tom

ranger335v
November 2, 2009, 03:06 PM
"That O Ring will flex differently from round to round depending on neck tension differences if the die is not snugged down well."

I don't see how that can be. The O ring serves to push the die UP, taking out any slack in the threads, and so does the effort to both size and seat. ??

Walkalong
November 2, 2009, 03:17 PM
Perhaps you are right. I do know folks have posted here about excessive O.A.L. variences and snugging the dies down helped it out.

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