223 splits with new ammo

[northernlightsglass]

I hope this isn't redundant, but I was shooting some '91 L.C. SS109 new ammo out of my Colt 223 upper and had roughly 10% of the cases splitting at the neck. Other headstamps had a number of splits as well (from a variety of suppliers, mostly reloads).

Can understand splits here on xth reload (work hardening of the neck) but was surprised to see so many on new cases. Never noticed this before.

Could there be something amiss with my chamber?

Also, noticed (under 60x tooling microscope) that my firing pin no longer came to a point, but ended with a dimple, as though another firing pin had hit it. I changed it out, but wondered if this could relate to the above.

Not much in the way of pressure signs, maybe one or two pierced primers (it was hard to tell) and primers somewhat flattened, but on a par with what I've seen with all my 223.

Anyone run into this before?
Thanks in advance.

 

[Otto]

Could there be something amiss with my chamber?

That's unlikely. The LC wasn't properly annealed at the factory and is over 23 years old....just throw the the splits in the trash and keep shooting. Split necks are common and rarely have anything to do with chamber, sizing or dies. It more of a symptom of work hardening and lack of annealing.

 

[northernlightsglass]

Thanks. Then I won't worry about it. I didn't realize that the ammo could age harden, but I guess it makes sense.

 

[moxie]

Hard to say, but with the splits happening on a variety of headstamps, the common denominator is the gun. Have it checked.

FWIW, I've not heard of Lake City botching their annealing. They take great pride in it. And 23 year old ammo is not old. It should perform the same as new production. In my experience, split necks aren't very common at all. A while back I reloaded a batch of about 1100 .223/5.56. Some of my own once-fired Lake City, some of my multiple reloaded brass, and a lot of very mixed range brass. I don't recall more than 1 or 2 split necks. It shoots well and I haven't noted any splits.

 

[DaveInFloweryBranchGA]

Sounds like you have a problem with your chamber. Could probably use the touch of a finishing reamer to smooth it out. That's a lot of splits and in more than one headstamp and source. Highly unusual and as Moxie said, the common denominator is the rifle and it's chamber.

 

[45lcshooter]

Ammo that old will tend to split, because who knows the condition that ammo was stored in from time it was manufactured til you got it.

I had brand new factory right off the shelf 30/30 Winchester ammo, split necks and shoulders. It happens to old ammo and brand new ammo.

Just toss the split stuff into brass bin, and cash it in after a 5 gallon bucket is full.

 

[Clint M]

Just wanted to add my 2 cents that's all it's worth. I wonder if the bullet has bonded to the neck of the brass case causing split necks ? This is more likely to happen with older ammunition, especially reloads where we clean necks.

 

[solvability]

I shoot ammo for WWII that does not split - I would shoot it in another gun and see if it splits - that would do it for me.

 

[moxie]

1. 23 years is not "old" for ammo.

2. Bullets don't just "bond" to case necks.

3. Cartridge brass doesn't just age and harden or split, unless it was poorly made to begin with AND you store your ammo in a barn. (no joke!)

4. Please provide empirical data on cartridge case cracking in brass cases, due to age, made by known reliable manufacturers and NOT stored in a barn. (again, no joke)

 

[Clint M]

Yes bullets do "just bond to case neck". This is a very well known issue and his information being they were also handloads 23 years of age adds so many variables to the constant any/all could have very well caused the issue. Case cleaning, case prep, sizing die (neck working, tension etc). You can google info on bullet stuck to case neck/bonded lots of info. I think this is more chance of happening being they are reloads.

That being said he could test the ammo in another rifle, he could try seating a bullet just enough to move it checking to if the bullet has stuck.

 

[horseman1]

I didnt see where this was mentioned:

Is the upper chambered for 223 or 5.56? Isnt that LC factory ammo 5.56?

May not have anything to do with it, but I thought I would ask.

 

[moxie]

Clint,

Per post #1 (read it) his primary problem was with FACTORY ammo, LC '91. And he ended up having the problem with those, other factory ammo, and reloads.

So, two or more groups of factory ammo (age and headstamp not provided for the other types), plus an unknown number of reloads (age not given) experience the same splitting problem when fired from the same gun.

Simple single common denominator. The gun.

 

[Clint M]

Dang I "thought" I read thepost

I even went back to re-read the post and still some how had reloads stuck in my head. I guess I read into mostly reloads to much. I was wrong.

Still regardless of cause I would fire ammo in another gun. Also one or two pierced primers is of concern as well.

I have a Colt LE 6920 I have had several AR's never had any problems with split necks or pierced primers factory ammo but mostly reloads. I would find the problem for sure before firing the gun any more.

 

[moxie]

Welcome to The High Road!

 

[Clint M]

Thank you for the welcome, not exactly my better first couple of forum post lol...