Need Better Dillon Expander for 9mm / .38 Spl

[Rattlesnake Charlie]

The Dillon expander is not large enough in diameter, or long enough, to keep my soft bullets from being swaged down to below .356. Does anyone make a Dillon compatible sizer for the 550 that is dimensionally identical to the Lyman through powder expander 38AP?

[nhyrum]

Are you sure it's the expander that's causing it? How are you going about measuring that they are getting swaged? Factory crimp dies are notorious for causing bullets to get swaged down. I've never had issues with my Dillon expander not being able to flare enough, but I'm using a 650 with the powder through expander, and it's super easy to crank it down to the point where it flares so much I can't get it back in the sizer without completely crushing the case.

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[Rattlesnake Charlie]

Getting about 1 in 10 keyholing in several different 9mm pistols. Not pistol specific.

Pulled bullet is .357 or slightly under. Guess that is not the problem.

Velocity averages 1170 fps. Maybe I'm pushing them so fast they are stripping rifling, but no leading in barrels.

Bullet is Lee 120 TC ran through a .358 Star sizer. Hardness is 15 BHN.

If I cast more of these I'll try slowing them down. The mold really cranks them out.

[nhyrum]

Keyholing usually is a stability issue, which means they need more speed. There's a handy stability calculator that you can put in your bullet dimensions and barrel twist rate and it will tell you if you're stable enough.

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[Rattlesnake Charlie]

Shot about 50 130 gr RNL and CCI 124 gr FMJ this morning also. None keyholed. They were at a lower velocity too. Bullets longer than the Lee TN. I'm perplexed.

[Petrol & Powder]

Lathesmith, a member of this forum, makes custom expanders for the Dillon 550.

I have a couple and they are TOP NOTCH.

And yes, the Dillon expander (Dillon lists it as a powder funnel) is not well suited for cast bullets. Lathesmith can make one that expands the case to a slightly deeper depth and to a larger diameter. He will also incorporate a Lyman "M" die style step that greatly improves the performance of the expander.

The custom expanders are a game changer and I highly recommend them.

[n.h.schmidt]

Some have run into this same problem when using the Lee powder through expander die for 9mm. Too short and too small for the oversized lead bullets. There was a easy fix. Ordering the Lee expander for 38S&W. Its bigger and longer. Oh Oh getting into dangerous waters here. If Dillon does not offer anything like this ,one could be made.
n.h.schmidt

[Conditor22]

I don't own a Dilloon but - https://lousgunwork.com/M-Neck-Expander-Powder-Dies.html

[sigep1764]

Lathesmith. His name is Chris and he won't disappoint. We are lucky to have a person with such skill and the drive to do this work for us.

[ioon44]

Lathesmith is local to me and a great guy to deal with, his work is always top notch.

[oldsman]

mr bullet feeder sells a lyman m style expander for the dillon , this is what I use on my 650
midway sells them

[1006]

It may not work in this instance, but I use an RCBS expander die before the case goes to the Dillon powder die. For me, it keeps the brass from gripping the Dillon expander/funnel and helps my 650 run smoother. I did notice that the RCBS expander goes deeper into the case before the belling occurs, and it seems to lightly expand the case below the mouth and thus helps with smooth seating.

[tomj44]

https://uniquetek.com/product/T1736

[Meatpuppet]

Two thumbs up on the Uniquetek HTC powder funnel. I load almost exclusively coated lead projectiles in 9MM (sized .357) on an automated Dillon press. The Uniquetek powder funnel solved projectile stability issues as the press indexes and the projectiles sit in the case almost perfectly aligned for the seating die.

The 9mm can be pesky.
(1) How are you sizing your brass?
(2) Are you seating and crimping in the same step?
(3) What are you taper-crimping the case to? I have heard that over-crimping the taper can cause tumbling in lead projectiles. My finished crimp for COATED LEAD projectiles is 0.378 to .380.

Here is a very good link about the science of 9mm Taper Crimps: https://czfirearms.us/index.php?topic=78873.0