Case Bulging To One Side at Bullet?

[BBDartCA]

I've noticed many of my 9mm & 40 s&w handloads have a big bulge to only one side where the bullet is seated. So in other words, the case has some eccentricity in this area. The below image (not mine) shows the bulge I'm referring to. Again, the bulge in my case is to only one side.

On some of the cases with the most pronounced bulge, I've had rounds fail to chamber completely - takes quite a bit of force on slide to eject unfired round. In the shop, these rounds also failed the plunk test. Eccentricity measured at the bulge is about 0.003" or so. Looking over some factory ammo, I can see a similar bulge to only one side, especially American Eagle 180g fmj 40's which some are about 0.001" max out. For both calibers using Lee 4-die set with Classic Turret.

What steps can be taken to minimize this bulging? Seeing this with fired and virgin brass. Couple different bullet types. Thanks!

 

[LiveLife]

With FMJ bullets with flat base, I get bulge on one side when the bullet gets tilted during seating.

To prevent this, make sure there is enough flare that will allow the bullet base to be inside the case neck when the bullet is set and seated straight without tilting.

If you continue to have problem with tilted bullet during seating, you may need to modify the bullet seating stem in your bullet seating die.

 

[1SOW]

bds +1

Either not enough mouth flare or something iin the case holder (like powder) is tilting the case. Especially with 9mm, the case holders are very 'loose'.
Is it happening every time or just once in a while.
If it's just once in a while, you may be loading to fast and not setting the bullet close to vertical in the flared case mouth, or it's not near vertical when the ram gets to the seating die..

 

[Blue68f100]

For those not feeding you may not be using enough taper crimp to remove the flare. That or your length is too long for your gun. Every gun likes something different in length.

 

[john16443]

The Hornady seating dies have a nice sleeve that extends below the die to guide and straighten bullets before they reach the actual seating stem. No matter how tilted or crooked I seat a bullet, they are always straight in the case with the bulge all around the circumference, not just on one side. I randomly roll a finished round on the granite countertop to check for wobble, never see any.

BBDartCA - you may want to try this roll test, if you find the nose of the bullet wobbles, they're not seated straight.

This, in addtition to making sure you're using the right seating stem for the shape and profile of your bullet should eliminate this issue.

 

[Walkalong]

If the brass thickness is not consistent, you can get this, or if you start the bullet crooked, you can get this. We would like to see the bulge consistent around the case, but it isn't always so. A different seater may do better.

 

[fields]

I adjusted my die so that it seats the bullet further up where the bullet has to be lined up better because it happens in a more narrow part of the die. This really helped.

 

[jr_roosa]

I got the Lyman M die to address this in .45ACP. It lets you start the bullet into the case a little more than a traditional expander does. Like everybody says, the problem is from the bullet getting crooked on the way into the case. I set aside the ones that won't drop into a case gauge and shoot them up at the range as practice ammo. They will usually chamber well enough to shoot.

I still need to try out my M die. Stay tuned.

-J.

 

[joneb]

This came up not to long ago,
http://www.thehighroad.org/showthread.php?t=642942&highlight=bullet+seating+off+axis

 

[rcmodel]

Are you by chance using a Lee shell holder?

They make two different ones for 9mm.

The Lee #19 is a "universal" size they ship with die sets that can be used for .30 Luger & Mauser, 9mm, .357 SIG, .38 ACP, .38 Super, .40 S&W, 10mm, 9x21, and a few others.

Of course, it doesn't fit any of the smaller ones correctly and center the case under the die like it should.

The Lee #6 is made specifically to fit 9mm, and does center the case pretty well.

rc

 

[BBDartCA]

This came up not to long ago,
http://www.thehighroad.org/showthread.php?t=642942&highlight=bullet+seating+off+axis

Wow, thats exactly my same issue ...

rcmodel ... thanks for the tip on the shell holder ... do indeed have a #19 and its a sloppy fit .. but 40 is a snug fit and my problem is worse on 40.

I notice the problem does not exist on 40 s&w rounds I built with a single stage press. SO I'm going to focus on my die set up and press operation as the possible culprit.

 

[bigfinger76]

Try this:
When seating, lower the arm until the bullet just seats well into the flare. Then release the handle, and try turning the cartridge 1/4-1/2 turn. Then seat fully.
If the bulging is no longer a problem, you'll know that they were just seating a little out of line.

 

[ranger335v]

Virtually every case has a thinner or softer side that will give way more easily when you seat, that's what causes the one-sided bulge you see. The problem is made worse by a sizer that's significantly tighter than it needs to be.

 

[PO2Hammer]

I noticed that happened when i used the Lee seating die in 9mm. I could see the seating stem tip to one side as it started to seat the bullet due to the sloppy threads and lack of a cone shape recess in the seating stem.

I switched to a Redding competition seater and the problem disappeared.

 

[Cherokee305]

BDS+2

 

[Sky King]

I've had the same problem with 45acp and 380 on my Dillon XL650. The way I corrected it is to loosen the lock nut on the seating die, insert a factory cartridge or one without the bulge, raise the cartridge up into the die and then retighten the locking nut. This will center the die with the cartridge.

 

[LiveLife]

I've noticed many of my 9mm & 40 s&w handloads have a big bulge to only one side where the bullet is seated ... Again, the bulge in my case is to only one side.

On some of the cases with the most pronounced bulge, I've had rounds fail to chamber completely - takes quite a bit of force on slide to eject unfired round. In the shop, these rounds also failed the plunk test.

What steps can be taken to minimize this bulging?

I normally do not get the "one sided" bulging problem even when loading 9mm FMJ with mixed head stamp range brass (slight bulging shown is same all around the bullet).

I ONLY get the "one sided" bulging when a bullet gets tilted during seating (bulging is only on one side, the other side is flat).