Bullet seating problem on Hornady LNL

[seektruth]

I'm just running my first 9mm on a Hornady LNL press, with Lee dies. It looks like I'm having a problem with the bullet seating depth. I set the dies and powder measure up, ran some through one by one and checked them out. Everything looks ok. When I run them through progressively, the bullets are seated 10 to 15 thousandths farther out. The only other cartridge I've loaded is .223, but I haven't had this problem with those. Any ideas?

 

[Hunter0924]

I would not think running more then 1 round through would affect COL. Did you readjust the seating die?

 

[SASS#23149]

I"ve had this same thing happen on my Dillon,and cannot explain it I just keep messing with it with ALL the dies full and it finally works itself out.

helpful,eh??

 

[seektruth]

I can adjust the seating die to get the COL I want when running them through 'progressively'. But, the COL is not as consistent as running one at a time, and it just doesn't make sense to me that it would vary depending on how I run them. But...maybe this is just normal?

 

[Luggernut]

2 things I've noticed.

-When I run only one round thru the press I tend to get more pressure on the lever and the rounds tend to seat slightly more.

-Depending on the seating insert I get varying depths. This usually happens with the insert that "pushes" the bullet in by making contact with the ogive of the bullet as oposed to the insert that is simply flat (i.e. for flat top bullets like .40 S&W). I suspect that the curves of the bullets are not perfect or completely consistent.

 

[Steve61]

I ran into a similar problem myself just the other week while loading some .223 on my Hornady LNL AP. I finally tracked it down to the Lee factory crimp die I was using. If I ran a round through the press all by itself, the OAL would be shorter than when I ran a series of rounds through. I also noticed that the first round in a series would be shorter than the subsequent ones.

In my case, I believe this was due to the factory crimp die pushing down on the cartridge and shellplate just enough to change the distance the seating die would travel downward.

 

[seektruth]

In my case, I believe this was due to the factory crimp die pushing down on the cartridge and shellplate just enough to change the distance the seating die would travel downward.

I was thinking about this some more, and I think you are probably right. One of my dies has to be set low enough that when a case is in it, the travel of the ram on my press is limited. The only one I know could do that is the crimp die. I'll check the adjustment of it later today.

 

[alohanole]

Also, you might want to consider they type of bullet vs. the seating stem you are using. I was having inconsistent seating with 124 gr flat point bullets until I switched to the flat-bottomed seating stem. Problem solved. I don't know how the 9mm Lee dies are packaged, but the Hornady dies include 2 stems.

Due to the problems with the crimping die in station 5 and the ejector wire, I use a Hornady taper crimp die in that station too. I have lots of Lee dies, but mix and match depending on the caliber to get the best results.

 

[seektruth]

Well, it was not the crimp die. It turns out that the size/decap die is causing this. It seems that no matter how I adjust it, the force of the cartridge being resized/decapped is enough to limit the travel of the ram by 10 thousandths. It's consistently and repeatably off by that much.

Here's what I have:
I get about 4-5 thousandths variance in COL as measured from bullet tip to the base of the casing if I run them all one at a time, or progressively. The problem is that running them progressively adds consistently 10 thousandths to the COL. This has been verified via multiple measuring methods.

This shouldn't be happening, should it? It certainly makes life harder for me, because it means that I have to readjust the bullet seater if I run any through without a casing in the first station. FWIW, I'm looking for an average 1.160" COL, which is how I set up the seating die with no other casings in the shell plate. So, I end up with 1.170" average COL when I run them progressively. Should I just set the seater another .010" in, and live with a few here and there (especially the last few of a run) being that much shorter in COL? I'm somewhat a newbie to reloading, and cautious, so I just want to make sure I do the right thing here.

 

[JFettig]

It happens to me too.
The plate thats on the ram is likely flexing a little bit. It does happen when I'm sizing and seating at the same time, when using a rifle FCD it does it too. What you can do is figure out how much of a turn it takes to make up that .01" on your seater die and make the adjustment when setting up or just running one round through it.

I've heard of it happening on others dillons. I don't really sweat it, it matters for some stuff but not others.

Jon

 

[Waldog]

I've had this problem when the nut holding the shell holder plate gets loose. I tighten the shell plate periodically and the problem goes away.

 

[Winger Ed.]

Me too.
I finally figured out that the shell holder plate was flexing also.

With the sizer die on one side of the circle, and the seater on the other:
the more resistance of a case in the sizer caused the plate to flex downward on the up-stroke,
which tilted the bullet in the seater farther up into the die than just using it by itself.

 

[jethro75]

I had the same problem with my LNL and as JFettig had mentioned I put marks on my seating die, one for single case and one for a full shell plate.

 

[rbt50]

sometimes the bullet will stick in the bullet seater and pull back up, make sure you have the right bullet seater .

 

[Walkalong]

With the sizer die on one side of the circle, and the seater on the other:
the more resistance of a case in the sizer caused the plate to flex downward on the up-stroke,
which tilted the bullet in the seater farther up into the die than just using it by itself.

I size cases first by running them through my Projector with the sizer only. Then I hand prime and run them through again without the sizer to load them. This eliminates the sizer which does have much more resistance and can cause the first two or three and the last two or three rounds to have a different O.A.L. due to a slight flex in the press.

Some bullets just seat more consistently as well. I will get + or - .003 to .005 from my target O.A.L. on some pistol bullets while others are almost all right on. The seater plug can also affect how consistent O.A.L. is from round to round.