What would cause this?

Seating stem. Bullet doesn't match the seating stem so it leaves a ring. Plated and lead bullets are more prone to it.

I’ll take a shot at this ,
Flat based bullet being pushed into a tight case without chamfering or lubing the neck ID identified by the seater stem marks left on the bullet.

9mm doesn't seat that hard. That would take a fair bit of pressure.

ericuda said:

9mm doesn't seat that hard. That would take a fair bit of pressure.

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Without resistance how else could a fella make an impression that deep ?

Maybe overcharged, can't compress any further?

The case would crush before that much bullet deformation.

Maybe the seating stem is hollow and is inserted backwards in the seating die?
It looks like someone smushed a tube down on top of that bullet.

Looks like a collet crimp die but not in 9mm.

The indention doesn’t match any seating stem I’ve ever seen. Is the stem installed in the die??

That was some serious force to deform the bullet that much. Has he double check his overall length and his setup in general, did something change to make it shorter. It would be hard to deform a bullet that much unless it was stopped on something in the case. The case itself probably could not support a bullet that well without crumpling.

If it shorter than normal it could be down hard on the powder charge, that is a dangerous situation in most cases causing gross over pressure.

If not shorter than normal it could be a double charge that it is seated against, again dangerous over pressure.

There are some 9mm cases out there with a substantial step in the case wall and thus a greatly reduce case capacity. That could be causing this issue and again could lead to overpressure issues.

It could be foreign material stuck in the case taking up room, tumbling media or similar.

I would figure out what is causing it before shooting that batch of ammo.

ballman6711 said:

View attachment 1053138
He said he wasn't having any trouble, and then adjusted something somewhere

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That phrase is always cringe-worthy in reloading.

ballman6711 said:

View attachment 1053138He said he wasn't having any trouble, and then adjusted something somewhere and now this is the result.
chris

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I’d ask just what he adjusted and go from there. Maybe he is now crimping and seating in one step? Could also be a stepped case, ask him what the headstamp is on that one.

My partially educated guess would be:

New brass (lots of internal friction)
Soft plated bullet
Seating stem not well matched to bullet
Seating die adjusted for far too much taper crimp

Results: Case is crimped hard as bullet is being seated, and so won't seat down without a lot of force due to case friction of virgin brass. Seating stem deforms soft bullet.

But it could also be, Col. Mustard in the Reloading Room with a Heavily Compressed Overcharge.

Just tell him to unscrew all his dies and start over.

That is not just a line, it's resized! Kinda like the looks of it though

Maybe crimping and seating at the same time with the die totally not adjust correctly/ Who knows??

‘Dummy round’? So no primer or spent primer? Please tell us he didn’t intentionally seat a bullet over a live primer with no powder.

Gotta be crimp misadjusted and clamping the bullet before it is seated all the way. Take the seating die apart, check for fod , clean -reassemble - readjust.
I suspect this answer because when I have done that the case crumpled instead of deforming the bullet.

Using .38 bullets? (9.1mm) ?

It does look kinda cool though.

Hence my hesitation to crimp and seat with the same die. I prefer separate steps.

ballman6711 said:

View attachment 1053138

A friend of mine is having an issue loading 9mm. He said he wasn't having any trouble, and then adjusted something somewhere and now this is the result.

Bullet is 9mm Everglades, not sure of the weight and don't know the type of brass. I suggested changing the seating stem but he only has one. I also suggested he adjust the seating die and it didn't help. Could it be stepped brass?

I can't go see it in person since him and his wife both have Covid and are quarantined.
Any thoughts on what is going on and a possible solution.

chris

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I bet 2 bullets are in the case!

That looks like a perfect seating of those new 9mm SemiWadCutters Horacio’s is making.

Bullseye is the new game, now that all these new pistol owners want to do something with their firearms, but found out running is a lot harder in real life than online.