"blown case head in .223..."

[exile]

A friend called me this morning to vent. He is loading .223 in preparation for prairie dog hunting. This morning he loaded some 50 grain Hornady V-max bullets using IMR 3031. Some of the loads he crimped, some he did not. Anyway, he got a blown case head, case seperated in the action. No apparent damage to himself or the Ruger rifle. The case that was blown was one he did not crimp. I do not load for .223 myself, so I did not know what to tell him. Any thoughts? Thanks.

exile

[NickSS]

This happens sometimes with shells that have been full length resized several times. What happens is that the shell stretches each time its fired to fill the chamber. eventually the wall thickness gets thinned out and then it separated circumferentialy. You end up with the head in your hand and part of the case in the barrel. If it separated in the die it was pretty far gone when he was sizing it. You can tell when a case is getting thin by a visible lighter area of the case in front of the head that is lighter than the case wall above and below it. Just toss these cases and you will be OK. If you want to have cases longer and you do not shoot a gas gun (semi-auto) just neck size the brass. If you are using a gas gun get a shell gage and only push the shoulder back about .001" when full length sizing. These methods will extend case life. But remember to inspect cases for excessive stretching each time you reload them especially with high intensity bottle neck cartridges.

[405]

Crimp would not have anything to do with it unless he was shooting stretched/at risk cases already. The only way crimping or not crimping would have a bearing is with overlength cases where the case mouth gets jammed into the lands (leade) thereby causing increased pressure. That increased pressure would then put a questionable case over the edge.... separation. But it would seem a crimped and overlength case would be more likely to do the bullet jam in leade/high pressure thing than an uncrimped case. So ???? on that.

Let's see- pdog shooting, lots of shooting, lots of shots, lots of shots per case, long range shooting, near max loads, maybe a tad of headspace in the gun, full length resizing and setting shoulder back each reload.... all adds up to case stretching just forward of the head. All or any of these or a few in combination seems the most likely cause.

Possible remedies- check length of cases and trim, check chamber length, check headspace in gun, set sizing die so resizing doesn't set shoulder back too far in relation to gun's chamber/headspace length, pitch cases after fewer firings and get new cases.

[exile]

I guess I wasn't too clear. The blown case head occurred when he was test firing the loads, not during reloading. Thankfully he was o.k. Sounds like it could have been any # of issues, not knowing any better, I thought perhaps since he did not crimp that a bullet could have been pushed into the case when cycled in the action, but like I said, I don't know.

Do you guys crimp your .223 loads or not? He said the guys he had been in contact with did not crimp, said they got better accuracy that way, but again I wouldn't know. Thanks.

exile

[Multigunner]

If he was single loading you can probably rule out a bullet pushed into the case.

If he uses once fired cases bought in bulk to handload for his rifle, some autoloaders can begin the opening cycle before pressure drops far enough, some military actions better suited to single base power curves will do this if ammo loaded with ball powder is used. This might compromise a case wall.

If none of the afore mentioned apply, it might just be a bad case.

I once had a box of Winchester .303 that had a high percentage of lengthwise splits in several different rifles, only had the problem with that single box of ammo.

When anything is mass produced by the hundreds of millions a few defective items will sooner or later slip by.

[405]

I guess I wasn't too clear. The blown case head occurred when he was test firing the loads, not during reloading. Thankfully he was o.k. Sounds like it could have been any # of issues, not knowing any better, I thought perhaps since he did not crimp that a bullet could have been pushed into the case when cycled in the action, but like I said, I don't know.

Do you guys crimp your .223 loads or not? He said the guys he had been in contact with did not crimp, said they got better accuracy that way, but again I wouldn't know. Thanks.

exile

No, I think everyone is on board about knowing what the situation is- separation during firing. Crimping is done for a variety of reasons including: habit, teacher did it, for tube mag guns so bullet won't jam deeper upon recoil, expected rough handling, ignition of slow powder, for revolvers so bullet won't pull during recoil, for really heavy recoiling rifles so bullet won't jam deeper during recoil, for some semi-autos so bullet won't jam deeper during cycling, etc. Generally, for bolt guns of the .223 type no need to crimp-- there should be plenty of neck tension from standard resizing that reduces the neck by about .002 smaller than bullet diameter.

Simply--- case heads in bottle neck/shoulder headspacing cartridges separate after X number of firings because they get stretched some upon each firing. Most often this stretching takes place just forward of the head and that's where most separations take place. How little or how much stretching dictates how long they last until they separate. On rare, very rare occassions a case will come from the factory that is flawed. Usually those flaws are longitudinal body cracks, neck cracks, folds, primer pockets/flash holes out of kilter, etc. Flaws like really thin walls just forward of the head seem to so rare that the previously mentioned possibilities seem much more likely.

[Heavy lead]

Looks like everybody's answered this thread pretty well. I reload and shoot lots of .223, for bolts and one AR. I do segregate brass per rifle and keep an eye on cases and reloading technique, I set back only .001 for the AR using a full length sizer and neck size only on the bolts, and never crimp even in the auto, never have had a case failure and hopefully never will, but I inspect every itsy, bitsy case too.
Not enough information without knowing reloading technique's. I'd like to know how many reloads the cases had.
Glad everything is good though with him and rifle.

[NSP64]

I had a reduced load in my .270win blow a case head, thought it was a double charge. once I got the case out I noticed it was too long. I trimmed all my cases I was using in my .270 (but had more un-inspected cases around) I only neck size my cases and don't crimp, but on that day I used some bullets that had a canalure. the uncrimped bullets were loaded to the canalure groove and when I chambered that 1 case it crimped the case mouth into the canalure. Scratch 1 gun.

[35remington]

Don't confuse a "blown case head" with a case head separation. You're somewhat confused by the incorrect terminology you're using. An overpressure event is different than a case head separation.

They guys have indeed correctly diagnosed that you have a case head separation, and they told you what caused it. In fixating on the crimp or lack of same, you're blaming an unrelated condition for the cause of your problems, when it's not the case.

Most case head separations occur during firing, as a severe crack would be noticed during the reloading step, but the faint light color circumferentially around the case forward of the expansion ring often is not and the round gets reloaded and fired anyway.

When the case shows this faint ring, it's already very thin there, and the pressure of firing causes it to fail.

A typical condition caused by an overworked case.

[NickSS]

Over the years I have experienced a number of case failures. Split necks, longitudinal splits in the body, head separations and blown heads (cracks across the case head). I am half deaf in my left ear due to a case head split while hunting with factory ammo first shot for the case. So I know a bit about causes. You can get a bad case from the factory that will fail some way at the first shot. Mostly this occurs as a longitudinal split in the body. I had a bad batch of Remington 22 hornet brass that 20% failed on the first shot and 50% on the second reload and these were not hot reloads. Most other case failures are due to multiple reloads and work hardening the brass or stretching of the brass. Case neck splits can be avoided by annealing the case necks every three shots or so. Head separations can be avoided by neck sizing and if you have to FL size size so as to push the shoulder back no more than .001 inch. Semi autos are hard on bottle neck cases for reloading. I shot service rifle in High Power competition for many years and if you are shooting a AR 15, M1A or M1 rifle you really need to be careful in inspecting cases. With good brass you will get about 10 reloads with full power loads in the AR 15 Per case and about six in the 30 cal rifles if you do not push the shoulder back to factory specs each time. I started watching how far I pushed the shoulder back when I noticed that I was only getting about three loads per case with my 308 in an M1a. By setting the shoulder back only .001" case life doubled. Seeing that I was shooting about 5000 rounds per year at the time this was a noticeable savings.

[c3d4b2]

The only .223 brass I have had trouble with was LC brace that had been machine gun fired. I used a sharpened paperclip to check for cracks on the inside of the case and was able to find the bad cases before things became exciting. Otherwise the most problem I have is with the necks wearing through at the shoulder.

[exile]

Thanks for the information. Like I said, I have never reloaded for the .223 before, so I am in the dark here. I know my friend does not clean his cases, so maybe there was a sign of failure there that he missed. Anyway, thanks.

exile

[Willbird]

Brass would have to grow very long for case length to be an issue, if you look at chamber drawings there is often an extra .05" to .06" there beyond the "trim to" length, and I sure have never trimmed a case .05" to .06".

I saw a 223 case that "blew" in an ar-15 once...it was an overload....the case blew out at the extractor....and the head had swelled so bad that it honestly looked like a belted magnum.....the gun was completely unharmed except needing a new extractor. Not my rifle or my loads, I was just a bystander.

Bill

[August]

The only .223 brace I have had trouble with was LC brace that had been machine gun fired. I used a sharpened paperclip to check for cracks on the inside of the case ans was able to find the bad cases before things became exciting. Otherwise the most problem I have is with the necks wearing through at the sholder.

Ding, ding, ding. We have a winner.

Since the O.P. did not describe the brand of brass, I'm goin' with the "former life as machine gun fodder" theory.

I have had case head separations in .223 after one reloading, when the case had formerly seen duty as a machine gun round.

I doesn't pose any serious treat in a modern rifle. Sometimes, however, the front half of the case gets stuck -- particularly in a hot rifle.

[cobrarolex]

Anybody experience 223 primer sidewall separation during decapping? Need help on this..

[Larry Gibson]

The use of a standard (unless you have a really tight match chamber there is no need for the SB or "AR" dies) RCBS X die to FL size .223/5.56 & .308W/7.62 cases, among several others, will negate incipient case head seperation (what I believe we are really talking about here). They will preven this even in "machine gun" fired cases most often and with cases that are FL sized every time they are reloaded. Always exceptions but the X dies are the best to use and you won't have to trim anymore.

Larry Gibson

[MtGun44]

Is he trimming his brass? I have personally witnessed three rifles blown up by too long
cases.

Bill