strange case creasing problem

[Grey_Lion]

have a problem I can't quite seem to diagnose to my satisfaction so I'm fishing for suggestions -

I've got my swaged .40 JHPs I've mentioned before.

Thing is - of late, when I seat them into the brass, they form a crease in the case .

The crease is not overly profound and doesn't prevent the round from chambering.

Thinking that perhaps over time and 800+ rounds, the sizing die used in forming the projectile on the swage press may have expanded, I took out my regular sizing die for .40 intending to pass the JHP's through them, but nay nay..... - the JHPs practically fell through the sizing die - projectile size is not the issue.....

The only thing I can come up with is that the lee bullet seating die , being made for shorter standard pistol projectiles, does not support the case sufficiently to the depth of my swaged JHP's - and the prolonged pressure of the seating operation slightly creases the case.....

Another thought that came to mind is some of these .40 cases have been fired and reloaded multiple times ( as is evidences by the glock ring further towards the head of the case ) and this is the last time I'll be reloading this brass as it won't pass my inspection the next time through.

Thoughts?

 

[Unclenick]

That's not a crease. It's just mirroring the location of the base of the bullet underneath. The sizing die makes the case smaller than the bullet, so putting the bullet in swells it back out again, but only as far as the bullet base goes.

You may not notice this on commercial loads because the newly produced case has slightly tapered sides. But your carbide sizing ring is just one diameter, so it makes the case straight as far back as it goes, exaggerating the appearance of that mirroring.

In your image, you can see the bullet base stopped at 7.4 cm on your ruler. The sizing ring stopped at the 7.9 cm mark. Between those two points, you can see the case is narrower than at the bullet and the reflection of the ruler marks are bent to a slight splay because of the ends of the narrow area widening back outward and pulling the brass into curves at the ends of the remaining resized portion.

Bottom line: it's normal. Go shooting.

 

[mikld]

Did you use a Lee FCD? Or perhaps the seat/crimp die rubbed on the slight bulge from the bullet's base?

 

[std7mag]

It is just as Unclenick said.
I've run into it mostly with heavier (longer) bullets.
If you are using the Lee factory crimp die, it is supposed to help smooth some of that out. But it won't get it all.

 

[Grey_Lion]

The crease happens whilst seating the bullet before going into the factory crimp die. The crimp operation doesn't appear to worsen the case crease.

I'm inclined to go with Unclenick's notion of what's happening.

 

[k4swb]

I only ever bell/flair the brass mouth. I do not use a case expander and allow the bullet to expand the case as it is seated.

I like it when I can see the bullet profile in my loaded ammo. Makes me know my brass has a good friction hold on the bullet.

 

[LE-28]

It's exactly what Uncle Nick said it is. Redding came out with a dual ring sizing die to alleviate that. The lower ring is slightly larger than the ring in a single ring die so it doesn't overwork the entire case from full length resizing.
https://www.redding-reloading.com/online-catalog/124-dual-ring-carbide-dies


With your swaged bullets, I have no idea how they would look. I would think they would work just fine. They are not cheap though and are offered in .40S&W

I would think a dual ring would be easier on your cases than a single ring die because of how deep you bullets are seated.

 

[Grey_Lion]

Had a chat with the die maker and he had one suggestion to try - set the bullet shallower for as much tolerance as my weapons would handle to reduce the crease due to the case taper. I'll see what I can get away with.
As these chamber fine in all my weapons, this issue is one of aesthetics and one of keeping the brass for future reloads with no crease.
But as I got a new swaging die over the summer that starts with a .40 case, I might just relegate all these cases to that effort going forward.