Dillon 550 crushing 9mm cases

[TargetTerror]

As I said in the other thread I have going, I'm loading 9mm Luger in a dillon 550, using Lee dies. Sporadically, but fairly regularly, I get a crushed/rolled edge of the casing during the expansion/powder charging stage. It's usually about 1/4 or less of the rim is folded in on itself.

This is obviously the Dillon die, since that stage is proprietary on Dillon machines. I looked in the die and at the funnel, and there doesn't appear to be any dirt or other nasties in there that might catch and push the rim in, at least to my eye.

I called Dillon and the said to try loosening the locknut on the die, then raising a case into the die and tightening it then. That would adjust the die a bit better and make things line up better. I tried that, to no avail.

I am putting a sizable flare on rim. I know its not ideal, but I've been too lazy to adjust the dies (it's a pita to adjust the flare on the Dillon). Could the cartridge be pushed up too far and possibly catching on something within the die? This seems unlikely though, as why would it only happen sporadically? Unless it is just an issue of different lengthed cases?

 

[Chuck Perry]

You should only bell the case mouth enough that a bullet can sit on it unsupported. The more you bell, the less case tension you will have to hold the bullet in place. This can cause bullet setback. Setback occurs when the round is fed into the chamber, or when the bullet strikes the front of the magazine when the pistol recoils. The bullet is pushed back further into the case. When the cartridge is fired, much higher pressure is generated because of the bullet being seated deeper than it ought to be. The higher pressure can damage your pistol, yourself, or both.
I would also check your shell plate adjustment. I don't have experience with the 550, but on my 650 if the shell plate is not set to advance properly it can cause the problem you are describing. The case mouth can strike the bottom of the die as the ram is raised, crushing it down. The usual culprit here is that the shell plate bolt is snugged down too tight, preventing the plate from fully advancing.

 

[BigJakeJ1s]

A couple of things come to mind... is the buckling always on the same side in the powder die? If so, it could be a faulty (off-center/canted) powder die, rough/burred expander/funnel, or faulty Lee sizer die.

Does it follow one slot in the shell plate?

Or, could it be that the cases aren't chamfered sufficiently?

Andy

 

[Snapping Twig]

You're flairing the case mouth too much IMO. Back off until you have a SLIGHT flair, just enough to hold the bulet when you seat it.

 

[woodfiler]

belling

The bell at the top should be .020 larger the the shell itslef. If you have the
directions that came with the machine, refer to those. I have a 650, i would
guess the adjustments are the same for the 550.

wood

 

[caz223]

Shellplate is too loose, allowing the case to 'rock' back and forth, making case pivot against the case retainer, and catching the case at an angle. The detent ball is now the high spot, instead of the shellplate being level.
Loosen the brass tipped screw, and tighten the shellplate until it doesn't easily push down, but still turns freely and detents as it should. Tighten brass tipped screw and try it again.

 

[caz223]

A quick visual check for this is to bring an empty to station 2 in an otherwise empty press, and raise the ram until the case almost touches the powder funnel. Holding it there, lightly press down on the shellplate in each of the stations. If there is a bullet present, then the 3rd station will contact the shellplate first, just as the case hits the powder funnel. At the right speeds it will interfere with expanding and powder charging. The empty case will wobble and come out of alignment when light finger pressure is applied to simulate this.