Ridge on Bullets

[nhglyn]

I have a Dillon 560 and have been reloading for 25+ years.  Loading 9mm rounds and I am getting a number that have a bulge that circles the case where the bottom of the bullet sits.  This has caused a couple of jams that lock up the slide in bullets that I didn't bother to chamber check.

 

Ran a bunch of non chamber checked rounds in practice and had the slide lock up a couple of times, and it was a bitch to rack it to extract the unfired round.  Had this ridge around them.

 

Zoom in on the picture and let me know if you have any ideas on why this is happening and how to get rid of it.  Probably happens 4-5 times per hundred.  I have double checked the dies and they all seem to be adjusted properly.  Using Montana Gold 347 gr CMJ that measure .355.  OAL is 1.150.  Crimp .377.  Once fired mixed headstamp brass with all military primed brass removed before reloading. 

 

Too lazy to pull the bullets so end up tossing them.  I am now chamber checking all rounds and tossing these bad ones.

 

So, why am I getting this?  And, how to fix?  Any ideas appreciated.

[Sarge]

Do you have a case gauge? What sizing die? My 9MAJOR rounds bulge too but they fit fine. Are you 100% sure the bulge is the cause of the FTF? Those particular bullets need seated fairly deep if I recall from my days of using them. They might be too long at 1.15 depending on the gun. Use a sharpie to blacken the bullets and drop them in your barrel and spin them. They should spin freely and not make any scrapes on the bullet.

 

A few of them look like they are slightly off center. What funnel/expander are you using?

 

FYI you can edit your post for a day or so. You might want to edit which press you are using and the bullet weight. Makes trouble shooting easier.

[HesedTech]

Not your crimp or OAL.

 

The issue is the brand of brass, the depth of the bullet seating and the bullet not being seated squarely as it is being pushed into the brass.

 

The subject is covered in multiple threads on the forum.

 

Summary:

9MM brass walls are tapered in size and thickness and in some brands the walls thicken sooner than others. This causes a more pronounced bulge for deep seated bullets.

With the thicker walled brass if the bullet is not perfectly pushed straight in it will bulge one side more than the other.

 

The only fixes are to sort out the offending head stamps, get different bullets (lighter and shorter), pre-expand before bullet seating (via better powder funnel or an expander) to get a more precise seating or just toss them after gauge checking them.

 

Never attempted to shoot ammo which hasn't been case gauge checked.

 

I use the Hundo case gauge check for every round. 

 

That's about the simplest answer, but do a search for all the threads which deal with 9mm issues.

[AHI]

Ill almost bet the head stamp is CBC.

Thear are a couple others but that seams to be the most offensive.