9mm Brass Issues: New XL750 possibly U Sizing Die?

[JordanC.eth]

Been reloading for years, but just upgraded to the XL750 for my handgun loads. I’m having issues with once fired brass coming out bulged. I’ve read that the U-Sizing Die can give a coke bottle figure to the brass after crimp, so maybe this is the case (pun intended) here. I can’t tell if my eyes are off and this is what’s happening or if something else is going on.

All brass feeds without issue and easily passes the plink test in the case gauge as seen in the photos.

I just want to be sure my head is in the right place with thinking it’s the die or if anyone has any feedback they wouldn’t mind passing along, it would be greatly appreciated.

Stations
1 - Lee U Sizing Die
2 - DAA Powder Funnel & Powder Bar / Dillon Powder Die & Hopper
3 - Mr Bulletfeeder
4 - Redding Micro-Comp Seater
5 - Lee Factory Crimp

 

[DiRTY DOG]

Try the Mighty Armory Gold Match FL TNT Sizing Die. (Currently on sale). Eliminate the bottleneck, and get rid of your Lee Factory Crimp Die.


Mighty Armory TNT Die will size your rounds to saami spec with the correct bullet tension. You can load to powder data spec and expect proper case pressures, cleaner burning powder, better accuracy and your brass will last longer for more reloads. Chronographs will prove SDs will be single digits. Now you can load your rounds to spec with every lever pull. Set your flare/bell to .380-.383 diameter. Taper Crimp to .376-.378 depending on the bullet diameter you are loading. We highly recommend pairing with our FL crimp die for best results.

TNT 9mm Sizing Die. Pair with our Crimp die.

Results will be better than factory sized loads!

Innovation for today’s volume reloaders and shooters that load for accuracy.

100% CNC Machined in the USA. Our specs and Steels are far superior to all others. You’ll see when you open the white box and experience it at the press and on the range.

Load to Powder Data. Shoot cleaner and definitely more accurate.

• 100% CNC machined in the USA.
• Includes primer flicker spring cap, shaft and pin.
• Concentric sizing.
• Modular design, no tools needed.
• Not an insert, will not loosen or crack.
• Sizes to spec. Huge advantages.
• Full length sizing, light lube recommended.

 

[acloco]

Welcome to 9mm reloading.

The coke bottle effect, is the norm.

 

[Kracken McGraw]

Could the die be sizing the case too much? My rounds don’t show bullet bulge like that.

 

[JordanC.eth]

Try the Mighty Armory Gold Match FL TNT Sizing Die. (Currently on sale). Eliminate the bottleneck, and get rid of your Lee Factory Crimp Die.


Mighty Armory TNT Die will size your rounds to saami spec with the correct bullet tension. You can load to powder data spec and expect proper case pressures, cleaner burning powder, better accuracy and your brass will last longer for more reloads. Chronographs will prove SDs will be single digits. Now you can load your rounds to spec with every lever pull. Set your flare/bell to .380-.383 diameter. Taper Crimp to .376-.378 depending on the bullet diameter you are loading. We highly recommend pairing with our FL crimp die for best results.

TNT 9mm Sizing Die. Pair with our Crimp die.

Results will be better than factory sized loads!

Innovation for today’s volume reloaders and shooters that load for accuracy.

100% CNC Machined in the USA. Our specs and Steels are far superior to all others. You’ll see when you open the white box and experience it at the press and on the range.

Load to Powder Data. Shoot cleaner and definitely more accurate.

• 100% CNC machined in the USA.
• Includes primer flicker spring cap, shaft and pin.
• Concentric sizing.
• Modular design, no tools needed.
• Not an insert, will not loosen or crack.
• Sizes to spec. Huge advantages.
• Full length sizing, light lube recommended.

I was actually looking into the TNT when I was putting the set up together, but they were out of stock at that time. Thanks for the heads up. I’ve heard good things, so I’ll probably go ahead and snag one.

 

[JordanC.eth]

Could the die be sizing the case too much? My rounds don’t show bullet bulge like that.

Yea that’s my assumption. It’s the “Undersizing” Die, so that would make the most sense.

 

[tommeboy]

Thats what happens when you load bullets 0.356"+. You can fix it by using an expander that goes into the brass farther than the one made for a 0.355" jacketed bullet. I use a 38 S&W powder thru die but I run 0.358" bullets in my 9mm

If they feed and don't lead then don't worry about it. But why would you even use the undersize die to begin with? It is not needed.

 

[Rsadams]

Oversizing plus a coated bullet which is .001 oversize....

 

[Rsadams]

If your using a lee oversizing die and don't need it get rid of it and by a normal sizing die... I just bought a 4 die set for 10mm and the sizing die carbide was screwed up.... I was on Amazon and was just going to buy another sizing die and replace instead of sending it in.... Only thing I could find in single sizing die was on oversizing die.... Anyway I just sent mine back and it's on its way back to me.... Never seen a need to oversize a pistol most chambers are big.... You can call Dillon and see if they can send out just the sizing die or call lee etc...

 

[JordanC.eth]

Sounds like I need to scrap the U die. Thanks everyone.

 

[Richard Jones]

Are you using range brass or just brass fired in your own guns? (ETA: Looks like all Starline, so prob. not range brass)

Also, the 'U' die can be adjusted out as well as in......

I wouldn't be so quick to scrap it just yet without attempting to tweak it a bit.

If I loaded that ammo, I would just shoot it and not worry about the shape.

Unless those are special order, those appear to be Blue Bullets which are usually .355.

 

[Richard Jones]

Just to add my next $.02, I load 9mm, 38 Super/SC, 40, and 45 on my Dillon and use a 'U' die for ALL of them. Wouldn't think about loading for an auto without one.

 

[fkimble@charter.net]

Never used an undersized die and never needed one. Your loads look fine. All I use is range pickup brass. The die sizes the case small enough so it will hold the bullet. When the bullet is seated it forces the brass out. When you force the loaded round through the "Factory Crimp die", you are sizing both the case and the bullet. You are making the bullet smaller and the lead does not bounce back . You end up sending an under size bullet through barrel. Not good for accuracy. The only use I see for the Factory crimp die is if you over crimp and make a bulge just below the crimp then it will remove the crimp while deforming the bullet. Your barrels are the ultimate guage for your guns.

Frank

 

[Kracken McGraw]

Never used an undersized die and never needed one. Your loads look fine. All I use is range pickup brass. The die sizes the case small enough so it will hold the bullet. When the bullet is seated it forces the brass out. When you force the loaded round through the "Factory Crimp die", you are sizing both the case and the bullet. You are making the bullet smaller and the lead does not bounce back . You end up sending an under size bullet through barrel. Not good for accuracy. The only use I see for the Factory crimp die is if you over crimp and make a bulge just below the crimp then it will remove the crimp while deforming the bullet. Your barrels are the ultimate guage for your guns.

Frank

That’s interesting about what all the Lee factory crimp die does!
To the OP I would look into a regular taper crimp die also then and pay attention to the measurements that Mighty Armory has printed above.

 

[Richard Jones]

Never used an undersized die and never needed one.

You've been fortunate.

Your loads look fine.

Agreed, FWIW.

All I use is range pickup brass. The die sizes the case small enough so it will hold the bullet.

I'm talking more about the head. The 'U' die is intended to size the head area more than a 'standard' die. When the case is belled to receive the bullet, it doesn't matter how small the die sizes the neck.

When the bullet is seated it forces the brass out. When you force the loaded round through the "Factory Crimp die", you are sizing both the case and the bullet.

I've never used a Lee factory crimp die so can't speak to that. Can the die be adjusted so that it only slightly crimps or is it a 'one and done' die?

You are making the bullet smaller and the lead does not bounce back . You end up sending an under size bullet through barrel. Not good for accuracy.

The entire bearing surface doesn't get smaller, does it?

The only use I see for the Factory crimp die is if you over crimp and make a bulge just below the crimp then it will remove the crimp while deforming the bullet. Your barrels are the ultimate guage for your guns.

Frank

This whole thread was about the case not going into the gauge before the crimp, not after.

I apologize in advance if this comes across as anything but an attempt to clear up the OP's issues. We each have our own experiences and experience. Mine is a bunch of years shooting USPSA competition with 38 Super/SC, 40 and 45. Lots and lots of range brass pickups would NOT gauge, either in a gauge or the barrel, unless utilizing a 'U' die. I never shot a 9mm in competition.

To the OP: Again, it just sounds like you need to crimp your rounds.

 

[acloco]

Revisiting this topic.

In checking the picture of the loaded rounds, where is the bulge? I see coke bottle shape, but no bulge.

 

[Hoser]

The coke bottle shape is ok. But if you switch FL resize dies it will go away.

The 9mm case is tapered and sometimes different companies carbide inserts dont take this into account.

 

[kenhwind]

My friend gave me some Federal once fired range brass he picked up and they were shot in a Glock (iirc) judging by the primer, and after resizing they would not go into my case gauge. They would chamber, but I realized that if I bought a LEE under sizing die I would not have to worry about it. This is the only time I have used one.

You could try the Redding Pro-Series dies which are set up to be used in the Dillon and or progressive presses.

Generally speaking, the resizing die makes the case too small for the bullet and the expanding plug makes the inside the correct size. because the 9mm is a tapered case in order to resize the base the case mouth gets undersized anyway. So yes, the case will have a bottleneck appearance.

 

[DiRTY DOG]

Many reloaders here don't blink at buying expensive RIFLE accessories: super fancy trimmers, $1k powder scales, custom dies and mandrel sets, annealing machines...

Yet their pistol setup is poorly thought out and as cheap as possible. "Just pick a color, green, red, blue, it doesn't matter." Folks often brag about how cheap their pistol setup is. But... they need to check every round with a case gauge and "correct" their loaded rounds with a Lee Factory Crimp Die (that basically force FL sizes loaded rounds into spec), because their dies do such a poor job.

There's a better way, and Mighty Armory has it figured out.

 

[AndrewB]

I loaded many, many thousands of 38 super , 40 and 9mm and I always use an undersize sizing die (EGW for me). They all have that coke bottle shape. They all also feed reliably every time. You can see the bullet base in the case as the case body is sized a little narrower this way.

I won't load pistol rounds without them. In either competition or in self defense, you want the round to feed and go bang. This helps ensure that

Make no difference in accuracy that I can tell. 25+ years USPSA competitor and at the peak, I shot 15,000 rounds a year. I might have missed stuff sometimes but the rounds always fed. I stopped using a guage once I started using the undersize dies because I never had those issues anymore..

My 2 cents.