Shoulder bulge

3

308Loader

New member
I was loading some 556 last night and found 15 of 100 loaded rounds had a bulge right at the bottom of the shoulder. Seemed to happen in the bullet seating proses, checked all of them with a case gauge before priming and after seating. Looks like some of the 15 might chamber and most wont. Any idea why the shoulder collapsed when seating bullet? Brass worn out? All cases loaded are mixed head stamp once fired(?) that I bought from local indoor range. First time ive seen this in the 2000 or so rounds ive loaded in this cal with same dies and methods.
 
Last edited:
Crimp shoulder in the seating die body is the usual cause of this. Back the die body out and the seater stem down to bring the COL back where you want it.

If you previously had the crimp correctly set and did not move the die, then it is likely the brass is too long and needs to be trimmed. Resizing lengthens brass, so always resize first, then trim.
 
If you are going to crimp bottle neck cases remember crimping only requires a hint of effort. The seating die does not have case body support; this was made very clear many years ago. It was said crimping bottle neck cases could be a bad habit because crimping can reduce bullet hold. Now you need to ask one of the many other reloaders that use tension. I have no ideal what effect reducing bullet hold has on tension.

Start by trimming all of your cases the same length, if you trim all of your cases to the same length you will have the same problem with every case or you will not have a problem,

I like 45 lbs +/- a few of bullet hold. I want all the bullet hold I can get.

F. Guffey
 
Thanks nick. As far as I know the die hasn't moved and all brass was trimmed to trim length. Ill reset the seating die and see what happens on the next batch.
 
308Loader, haven't had that happen. Use to reload 223 now only 308, 5.56 is thicker then 223, I'm only guessing though, the sized OD from the empty sized case fits the gauge but the seating causes the problem. Did you check the neck thickness & inside neck dimension. When seating the bullet is there more resistance. I know military chambers are larger, are you crimping your rounds. Is there a separate die for 5.56 & 223. Just my way of thinking, hope I helped in some way. Be Safe Chris
 
Yes, to put it into just a few words, applying excessive pressure to the crimp causes the case to bulge just below the shoulder since the case is not supported within the die at that point. Usually the bulged cases will not chamber. Now some have reported they have ironed out the bulge by removing the decapping stem and lubricating and sizing the loaded round. However I am not advocating that and although that seems to work OK, prefer to disassemble the rounds and resize the cases.
 
I am loading for 556 AR15. Using RCBS SB TC die set (black box). When I initially set up dies I set for very light crimp. I'm using lee press and have lock rings on die to keep them from moving. I didn't feel any extra force being applied when seating. looking at the head stamps of the bad ones 13 are 223 fc , one fc 19 and one lc 01. As far as resizing loaded round no thanks, ill chuck them in the bin at the range and chock it up to another learning experience. Thin wall 223 brass?
 
No need to throw them away, get an inertia bullet puller if you don't already have one. But those lightweight .223 bullets can be difficult to dislodge, especially since they have been over crimped. I also do not like the idea of resizing the loaded rounds to iron out the bulge. Possibly the main objection would be getting a stuck case, not a good thing to do with a loaded round.
 
No big deal, to me for a small batch it simply isn't worth trying to save them. Funny how several of us knew what happened, want to guess how we knew. Been there, seen it happen to us. I make sure to back my die back off the crimp length by quite a bit, just to make sure, then adjust the seating stem down to where I want the bullet to be.
 
Possibly the main objection would be getting a stuck case, not a good thing to do with a loaded round.
Click to expand...

If the case body/shoulder juncture is upset/bulged the problem will be closing the bolt. There are shooters that are stubborn when closing the bolt; they can 'actually' sized the case when closing the bolt. When fired the sized in the chamber case is ejected just like a case that fit the chamber perfectly.

223 bullets can be difficult to dislodge, especially since they have been over crimped.
Click to expand...

There is no such thing as over crimping; again, before the Internet it was suggested crimping could be a bad habit meaning bullet hold can be reduced when crimping bottle neck cases. And then there is R. Lee and his book in modern reloading. He has a section on crimping. I am beginning to believe most books are written in a foreign language.

F. Guffey
 
terminology again
Click to expand...

Forgive;
how about if I substitute heavily crimped.
Click to expand...

For years and years I have said the crimp die does not have case body support and the case will not support a heavy crimp. I have crimped cases with case body support, I have crimped cases with full length sizing dies with carbide rings. After hitting the Submit Reply button I have backed away from the computer and before I could take my hand off of the mouse someone has posted a reply and said "No you can't and if you did you would have crushed the bullet and the bullet would have been loose"; even after I gave the rational for the method and or technique for crimping with a full length sizing die.

F. Guffey
 
Well there is a difference between lightly crimped and heavily crimped so I'll still maintain that the crimp is on the heavier side when the shoulder is collapsed. Your turn.
 
Funny this is the first time I've had this problem in over 2000 rounds loaded. also that the bad ones are almost all 223 brass.
 
Is it different 223 than what you had?

I now crimp in a separate step from seating.

Bad results from time to time, easier to control the setup
 
Do you have to crimp a 223 or 5.56 round ? I shoot 308 no crimp without a problem. I roll crimp for my 44 Mag. revolver.
 
I'm not saying the only way to bulge the shoulder is because of too much crimp, but that's 100% of the source of the bulged shoulders I've had with .223. I started with brass all trimmed to the same length, but over time some grew longer than others, even though they were shot in the same AR15 with the same powder charge. That small difference was enough to bulge some of my rounds when I reloaded them later.

I no longer crimp .223 for my AR. I made six dummy rounds for practicing malfunction drills, and I didn't crimp any of them because I wanted to see what sort of bullet setback they'd have. After running them through the gun a couple of dozen times, they still have the same OAL. I very much doubt my live rounds will suffer bullet setback since they'll make exactly one trip through the gun for each reload. As always, YMMV.

As for 5.56 brass being thicker than .223, from what I've read some 5.56 is thicker than .223, and some .223 is thicker than 5.56. Same with internal capacity. In short, there is no firm guideline on case thickness or internal capacity differences between the two. It's all subject to the manufacturer.
 
RC20 the lot of brass I have is completely random. Mostly LC brass (80% probably) witch I would assume is 556, or at least the few hundred that I bought and shot are. The rest of the lot is indoor range pickups, lots of different head stamps.

Guess I should be sorting by head stamp before I load. I reset the seating die (no crimp), we shall see what happens on the next batch. hopefully neck tension alone is enough.

As usual, thanks for the input all:)
 
Guess I should be sorting by head stamp before I load. I reset the seating die (no crimp), we shall see what happens on the next batch. hopefully neck tension alone is enough.
Click to expand...
I've read that the best way to get consistent results, in both the reloading room and at the range, is to use brass that all have the same head stamp. Given the variances between manufacturers, that makes sense to me, so that's the method I use.

I've also read of people who sort brass with the same head stamp by weight and alter their loads accordingly. That makes some sense too - given the slight variances within a production batch - and if I were striving for extreme accuracy, I'd consider it. However, that's a little more work than I find necessary for range fodder. I'm striving more for consistency in everything working properly and getting the longest life out of my brass.
 
Your turn
Click to expand...

WOW! FRIENDLY ALERT:

Many years ago it was said crimping bottle neck cases can be a bad habit and if the bullet does not have a groove around it for crimping; don’t crimp. Dillon took it further; they thought it was a bad habit to seat the bullet while crimping because once the crimp bites into the bullet while the bullet moves down when seating the case had no choice but to bulge.

Again; the seating die does not have case body support. Crimping only requires a hint of effort, I have Herter presses that with handles heavy enough to fold a case when seating. If I am going to crimp I am going to trim my cases to the same length and I am going to adjust the crimp first and then the seating plug.

I have a small green machine that puts groves in bullets, I can put a groove anywhere I want it, I do not use that little green machine but I have it JIC. Crimping a bottle neck case can lesson bullet hold.

F. Guffey
 
You must log in or register to reply here.
Back
Top