Dillon 550 Bulge in brass

[DS26]

I have been reloading 9mm ammo for years this said I’m no expert!

I always chamber test every round before I bring them to the range lately I started to have an unacceptable amount of failures 3-4% they all seem to have a slight bulge just above the rim.  I have attempted to adjust my first stage case resizing die I seem to be able to make it worse but having a hard time making it better.  I’m hoping someone can share with me a trick to setting this die or tell me what I might be doing wrong.

[RJH]

Use a Lee die for your resizing. If the base bulges much after that, the brass is probably shot out of a major open gun and is just junk.

[Farmer]

First off is your die contacting the shell holder firmly? If not you may be contributing to the bulge by not resizing as far as possible. Even though they may not have the “Glock bulge” you might just run them through a bulge buster to iron them out. Be forewarned that if they are stretched excessively they may be thin and should just be tossed. I had some “glocked” brass that I busted and even though they load fine they are right at 35 fps slower than the same brass that’s not been busted. Just something to note when at the chrono. 

[PhotoRecon]

Seen the same problem with brass fired in a oversized chamber.

 

Tried the U die etc. but my roll sizer made it easy to remove the bulge.

 

 

[392heminut]

A regular sizing die can't size all the way down but the Lee dies seem to get about as close as possible. The only way to get rid of the bulge is with a roll sizer or a push through die of some sort. 'Glocked brass' was a big issue several years ago with the first generation of Glocks but that seems to have been resolved for the most part and you don't see that much anymore. I agree with RJH that the brass was probably shot in a 9mm Major Open gun and it's best to just toss it. My best friend shoots 9mm Major in Open, and he never picks up his brass to reload it. He says "One and done!"

Edited February 28 by 392heminut

[DS26]

I have been buying cleaned once shoot mixed brass so I don’t know what it was fired from but not likely major loads.

[Dr Mitch]

The extremely bulged case web OP described is becoming more common.  I’ve had more in the last month than in the previous five years.  Some model of gun out there must be responsible.

[Braxton1]

2 minutes ago, Dr Mitch said:

The extremely bulged case web OP described is becoming more common.  I’ve had more in the last month than in the previous five years.  Some model of gun out there must be responsible.

 

I wonder if it's coming from the proliferation of PCC's in the market now.  Most of them are blowback operated, so they're "unsupporting" the case web faster than a short-recoil or gas-operated system.

[Dr Mitch]

I think it’s a handgun 100%.  Not many PCCs in this neck of the woods.

[PhotoRecon]

I learned about the bulged case back in the 90's when brass fired in my Smith 5906 wouldn't chamber in a quality 1911 9mm. After that anything fired in the 5906 was kept separate.

 

Brass fired in machine guns with bulging was all over as well.

 

My guess is a loose chamber was an inexpensive way to ensure reliability.

 

I've been shooting major for years and never experienced bulging. The primer pockets would eventually loosen up, however. I have seen case ruptures in brass by Win, Browning and Herters. Never a problem with Blazer, FC or R-P with major.

[RJH]

Could be a sig 320....

[HesedTech]

On 2/27/2024 at 7:43 PM, DS26 said:

 I’m hoping someone can share with me a trick to setting this die or tell me what I might be doing wrong.

Not doing anything wrong, die can only go so far down.

 

Here's a trick that works in non-auto feed presses; grind the beveled flair out of the opening of the die. Make sure you smooth the edge to prevent scraping the brass.

 

Used this years ago to combat bulged brass and make sure sizing made it all the way to the shell plate. But, only works if one is hand feeding in the brass.

 

I bought a roll sizer, an expensive fix.

[38super]

RJH has the best answer, flat primer may be the only indicator of Major 9.

[Farmer]

A lot of High Points in the area?? 

[Squirrel45]

On 2/27/2024 at 10:30 PM, RJH said:

Use a Lee die for your resizing. If the base bulges much after that, the brass is probably shot out of a major open gun and is just junk.

I had the same issue, tried Dillon, mighty armory, rcbs and Lyman. Finally one day I tried an old Lee resizer, you got to be kidding. After trying dies that cost x5 the Lee worked go figure

[Tunachaser]

Also a fan of the Lee U-die. Fewer rounds not passing case gauge.

[DarthMarl]

I need to try this lee die

 

[DS26]

I bought a Lee die set and to my surprise it seems to work better however the primer punch design is terrible. If the case is difficult to punch out it forces the entire rod to push up and no longer work.  
the Dillon has a spring loaded design if it has trouble pushing out a primer it pushes up then the spring resets back in place and you keep going.  Is it possible Lee makes a better model then what I bought?

[Farmer]

2 hours ago, DS26 said:

I bought a Lee die set and to my surprise it seems to work better however the primer punch design is terrible. If the case is difficult to punch out it forces the entire rod to push up and no longer work.  
the Dillon has a spring loaded design if it has trouble pushing out a primer it pushes up then the spring resets back in place and you keep going.  Is it possible Lee makes a better model then what I bought?

That’s how they are designed so it doesn’t break the decapping rod. You just have to re-set it manually. The price reflects the difference. 

Edited March 4 by Farmer

[xrayfk05]

Snug up the nut on the Lee die a bit more to prevent it from moving so easily.

The spring on the Dillon die does not prevent breaking pins, it's supposed to prevent primers from getting pulled back into the case after depriming. Ironically enough most people having issues with primers getting pulled back are using Dillon dies. 

[Sarge]

5 hours ago, DS26 said:

I bought a Lee die set and to my surprise it seems to work better however the primer punch design is terrible. If the case is difficult to punch out it forces the entire rod to push up and no longer work.  
the Dillon has a spring loaded design if it has trouble pushing out a primer it pushes up then the spring resets back in place and you keep going.  Is it possible Lee makes a better model then what I bought?

Tighten the collet more. The pin is supposed to move before bending or breaking.

[392heminut]

13 hours ago, Sarge said:

Tighten the collet more. The pin is supposed to move before bending or breaking.

Yup! I also use a brass hammer to tap the pin back down, it saves having to use a couple of wrenches to loosen the collet to reset the pin every time. I started doing this when I was getting that damn Norma crap in my 9mm brass.

[OnePivot]

I lightly scuff my lee pins and crank them down. I don't want them slipping, ever. Squirrel daddy pins will punch out norma brass too. 

 

Sometimes lee dies need a little polish, but they work incredibly well. 

[Farmer]

I had to take my Lee nut out and clean it up. It had chips in the slots and the threads were rough. Dug out the chips, wire wheeled the nut and now it’s easy to get tight. 

[Tejas]

I use a FL Redding resize die and make sure it is almost contacting the shell plate. I reload range pick up brass where people shoot 9 major frequently. Sometimes there is a case that is tough to run through or it cracks during resizing. But I've never had issues with the final product except for raised primers which is on me.