I posted this on the general discussion forum,thought I'd post here also. Today I was shooting a hand load that had been carefully worked up,well below max,fresh brass,no high primers,have fired close to 1000 with no problem,no headspace probs etc,etc. The last mag full was going fine and then there was a BIG KABOOM and I was hit across the face,neck and left arm with blowback. Looking at the rifle,the mag was as in picture and the bolt release latch was broken off. I had to tap out the case with a rod and my theory is... from the appearance of the case,it had entered the chamber slightly skewed and the bolt collapsed it enough to allow it to fire. If you look closely at the pics you can see the case tweaked to one side and collapsed. With the bolt out & rd in chamber,I can see that the case web is cocked to one side slightly.  The mag it was in is one that I'd had some feeding problems with before (black follower)to the point that I'v had some bullets pushed back into the case. (thought I'd left it at home today). Does it sound as if the mag was to blame? I don't really want to experience this more than once. href=Case 1
Case 2
Case 3
Blown Out Mag

Did it go off with or without a trigger pull?

Its virgin(never fired) WW brass and I did pull the trigger. Also I forgot to add, the case came out with a very slight push of a cleaning rod,almost no pressure,didn't have to beat it out.
NW
Edit- Now I wonder..someone in the other section suggested a low powder detonation or a faulty case? Either could have caused the web to be blown sideways .

Quoted: The mag it was in is one that I'd had some feeding problems with before (black follower)to the point that I'v had some bullets pushed back into the case. (thought I'd left it at home today). Does it sound as if the mag was to blame? I don't really want to experience this more than once. Case 1 Case 2 Case 3 Blown Out Mag

If the bullets had previously gotten pushed back in the case, that would be a very likely cause of your KABOOM.

A load that was near max, even if worked up safely, could become a dangerously high pressure situation if the bullet was seated deeper during the feeding cycle.  Too deep, and cocked sidways at the moment of detonation would raise pressures even more dramatically as the bullet tries to enter the rifling skewed, even a few degrees.

I would nail that dead magazine body to the wall over your reloading bench as a reminder...and start using bullets that have a cannelure to crimp the case neck into.

Paladin

Did you size your new brass before loading?

Did you use cannulered bullets with a firm crimp?

Were you loading any pistol cases before you loaded the rifle cases?

Yep the brass had been sized and the 223s are the only thing I'm loading that takes a small primer.

If the bullets had previously gotten pushed back in the case, that would be a very likely cause of your KABOOM.

I think this has to be what happened,and as the mag is way dead I probably shouldn't have to worry about it again. Bet I might have a slight flinch for awhile now?

So, are you guys saying never reload any .223 for the AR without a cannelure and crimp?  Please.....

How in the world do you get a buldged ring around the case that high?  Was the ring inside or outside the chamber when you tapped it out?  It looks like the case balloned at that ring and then the gas escaped on the side that became weakest .  That probably caused the skewed look of the case head.

Could your case neck have been too long?  I've had a Wincheter case or two that was too long out of the bag.  The bullet might have been held too tight with an overly long case and caused the pressure to spike.  That, or bullet setback could be at play too.  I'm not expert at this so I'm just as interested to know the outcome as you.

..someone in the other section suggested a low powder detonation or a faulty case? Either could have caused the web to be blown sideways .

No way do I see it as being a detonation.  Detonations (if you believe in them, there are some people who think the whole theory is hooey) blow the gun to tiny pieces, such as the what happened in the photo David-Hineline posted in the General Discussions forum.  In your case, the rear web of the case has simply blown out, either due to brass that couldn't handle the pressure or from the head being unsupported at the instant of firing.

The bolthead does not support the casehead fully at the extractor.  In an overpressure situation, this is where the case will fail and vent the gas.  

As to the cannelure and crimp question, I want a good crimp and cannelure on all my reloads for revolvers and autoloaders.  I satisfied my curiosity on this subject by making some proving dummies up with brass and bullets I wanted to use.  Multiple hand cycling showed more bullet setback than I am comfortable with on an AR, and setback was awful on 45ACP.

Different dies and brass combinations will give different results as to neck tension.  See what works for you.

DID you full-length resize?  What kind of die do you have, and do you use a case lube?  I'm wondering if you didn't pull one on the way down, which got crushed when it got chambered.  Internal volume went way down, pressure went way up and it went kb.

I'll try to get a close up tonite,left the camera at work last nite. The carrier is fine,but looking a little further I noticed the extractor is bent . The blowout on the case would have been more or less at 4-5 O' clock position in the chamber. The sizing die is a FL Redding and I use One Shot.
NW

i never crimp.

just pull the expanding plug, and use an M die, no cannelure needed. hell for max tension dont even use an M die. there is no way it will move then. or use the M die the first couple of thousandth then seat the bullet.

Here 'tis. It only took me 17 shots to get one in focus! Also the case slid right out of the chamber with one light tap of the rod,none of the "stickieness" that I'v seen with with overpressure loads. If I would have had to beat it out with a rod,I would have thought,"I screwed up BAD!",and probably wouldn't even have mentioned it. href=Case

Sure looks like serious overpressure to me.  See the brass swell into the ejector area?  Even the lettering stamps are swelled flat.

Were you using virgin brass for your reloads, or fired brass?

I'm wondering if the case had a thin area above the head from prior stretching.  I've seen a shiny ring develop there, indicating a case head separation is slowly developing.  Perhaps such a thinned area merely "blew out" thru the extractor region where less support is present.

Paladin

Quoted: Sure looks like serious overpressure to me.  See the brass swell into the ejector area?  Even the lettering stamps are swelled flat.

Thanks for posting the case head pic.  That helps.

I'd have to agree.  I can't see any other way for the brass to be forced into the ejector hole like that.  You can also see a ring around the firing pin mark where it looks like the primer got pushed into the FP channel.  I doubt it was just bad brass that did that.  The case looks like it was flowing into everything.  I'm not sure why it wasn't more sticky but those marks are not from the force of the bolt collapsing an oversized round.  Those seem to be extreme pressure signs.

If you are positive on the charges then I'd suspect severe bullet setback here.

Thanks for the replys. As I'm pretty anal re loading procedure and I'd had problems with the mag before,I'm going to think it was a bad feed and bullet set back that caused the blow up. One thing,what looks like brass flow in the ejector area is actually where the case rim is torn/ripped. Anyway a good object lesson other than wearing safety/shooting glasses,any other mags that I have a problem with I'll dismantle immediately while I'm waiting on parts. At least now I'v got a  punch set,spare parts,etc ordered that I'v been wanting! Thanks again,
NW

Quoted: One thing,what looks like brass flow in the ejector area is actually where the case rim is torn/ripped.

I'm not sure you understand what area we are referring to:



See the area being pointed to?  This is where brass "flowed" into the ejector (not extractor) area.  This only happens when the bolt is fully closed, an extreme overpressure occurred, and the brass as literally being shoved into tho the hole where the springloaded ejector resides.  It is a common area to look for overpressure, and yours is the most pronounced ejector flow I have seen.  Couple that with the flat primer, firing pin dish, swelled web, and blown out case in the extractor (least supported area) and that's just classic overpressure.

What was the load you used, out of curiosity... including bullet, powder, charge, OAL, and primer?

I'm not arguing that it wasn't way over pressure! I was looking at the backside of  that area,and there appear to be cracks on either end of it. Possibly brass didn't flow back into and fill them up? I don't know.The load was a Sierra 55 gr HPBT over 24.7 grs of H335. OAL 2.240 and a Federal 205M. Book max is 25.7. I generally scale every 10-12th charge,but thats not to say of course that a bloop could'nt have occurred,but I don't remember ever having one over or under 0.4 grain.  Ball and flake powders have both run  consistently at +/- 0.2 grs.

Quoted: I'm not arguing that it wasn't way over pressure! I was looking at the backside of  that area,and there appear to be cracks on either end of it. Possibly brass didn't flow back into and fill them up? I don't know.The load was a Sierra 55 gr HPBT over 24.7 grs of H335. OAL 2.240 and a Federal 205M. Book max is 25.7. I generally scale every 10-12th charge,but thats not to say of course that a bloop could'nt have occurred,but I don't remember ever having one over or under 0.4 grain.  Ball and flake powders have both run  consistently at +/- 0.2 grs.

Are these the puppies with the wide hollow point?  If so I even more suspect set-back as your issue.  I had my rifle bind up on one when I was shooting too.  This was in a good mag with no prior issues.  It set it back pretty good as the HP hung up on the feed ramp.  My ramps and chamber were dirty and pretty dry at this point.  Had that round slammed on in I might have had a bad day.  

I stopped using them.  No need to tempt fate you know.  Either that or start crimping them with the Lee factory crimp to help keep 'em from ramming into the case if they stick on the ramp.  The small match hollow points in the heavier bullets have never hung up on me.

interesting....

overpressure signs on a unit of mine that broke the bolt a couple of weeks ago....no KB, but maybe i was lucky....

Quoted: interesting.... overpressure signs on a unit of mine that broke the bolt a couple of weeks ago....no KB, but maybe i was lucky.... onfinite.com/libraries/366610/8c3.jpg

Whats the story there?

Quoted: Are these the puppies with the wide hollow point?

I don't think so,at least they don't look any wider than the HP on the 53 gr Matchkings. I do have a FCD,but haven't used it as I haven't had any setback in the mag or in rds that have chambered. Now I'm feeling a little more inclined that way. IIRC one of the earlier misfeeds I had was with SSPs. That was the last of the box of HPs anyway,and the rifle seems to shoot  V-maxs a little better so I'll stick with them for now..and hope nothin' else blows up!

here ya go FALARAK....

www.ar15.com/forums/topic.html?b=3&f=66&t=227506

I agree with the overpressure thing - but why did it overpressure?

Handloads 90% of the time are just double or over-charged, or other user mistakes were involved.  But, if it's something in his weapon he deserves to know about it.

Quoted: I agree with the overpressure thing - but why did it overpressure? Handloads 90% of the time are just double or over-charged, or other user mistakes were involved.  But, if it's something in his weapon he deserves to know about it.

-His shooting many of these loads previous with no issues seems to indicate no systemic issue in the rifle.  

-Double charging a 223 case is pretty hard as it has such small capacity, and a double charge is usually catastrophic in it's destruction of the firearm.  I seriously doubt that.  

-He's a grain under max which means a stray heavy charge would be pretty hard to see as the reason.  

-A weak case wall/web would not cause the case head to flow into everything I wouldn't think.

My bet rests squarely on a set back bullet or an over-length case neck.  It seems like that or a terrible compound coincidence.  That would explain the one-off nature of the event and a previously safe load becoming dangerously over-pressure.

That's my take but I'm curious to see if anyone has a different view.

interesting discussion as always gents....

this KB, and other overpressure (OP) issues is something i would sure like to see more information and checklists for AR-15/M-16 type rifles...

maybe some info in the FAQ section here might be appropriate if it does not exist already???

i would think some basic system checks for OP conditions with pictures of deformed brass, etc. would be a good thing to have available for the community...

probably already exists, but i'm not aware of it.....maybe some of you can steer me in the right direction>?>?>?  

Quoted: Quoted: maybe some of you can steer me in the right direction>?>?>? steered

Why is it you keep pointing people to a FAQ in which none of the articles work anymore?  

Quoted: interesting discussion as always gents.... this KB, and other overpressure (OP) issues is something i would sure like to see more information and checklists for AR-15/M-16 type rifles...

What kind of additional checklists do you need.  Every AR manufacturer warns not to use reloads in their products.  And most (if not all) state there is no warranty coverage due to damage from reloads.

SOP for reloading ammo for semi-auto weapons is heavy crimp and cannelure.  Crimped primers are also recommended.

Actually there isn't a firearms manufactor at all (that I know of) that doesn't warn agains't using reloads in their product and all will void the warranty if you do so. SOP. In my 10-12 load manuals I'v found no recommendations for a crimp/cannelure other than if you find its necessary to avoid setback in the mag,and absolutely none for a crimped primer. Could you cite your sources? I don't know for sure,but I think in my case even with a heavy crimp the bullet would have been set back due to the force of the bolt. I might load up some crimped dummy rounds and try to simulate a misfeed,just to see.

Quoted: Actually there isn't a firearms manufactor at all (that I know of) that doesn't warn agains't using reloads in their product and all will void the warranty if you do so. SOP. In my 10-12 load manuals I'v found no recommendations for a crimp/cannelure other than if you find its necessary to avoid setback in the mag,and absolutely none for a crimped primer. Could you cite your sources? I don't know for sure,but I think in my case even with a heavy crimp the bullet would have been set back due to the force of the bolt. I might load up some crimped dummy rounds and try to simulate a misfeed,just to see.

Reloading gas gunz

Most of the info on loading for these weapons is now considered common knowledge in the ammo industry.  If you want sources, start researching ammo development by the US Army circa  early 1900's.  The cann. crimp and crimped primers are there for a reason, not looks, and not for water seal either.   You found out one of the reasons.  The extra manufacturing steps on military ammo don't stop all mishaps, but they significantly reduce them.

Along the same line, I bought a screw driver yesterday, and It did not come with any documentation as to which end I should hold.

I understand his point of view and he's not wrong about the risks involved in reloaded ammo.  However I know for a fact there are horror stories about factory ammo too and plently of people who have had pretty unpleasent injuries from it.  It's not defect proof either.  There are risks involved in just shooting and there are elevated risks involved in reloading.  It can be done safely and those risks reduced but setting off a bomb three inches from your face has a basic level of risk attached.

I had a factory round with a bullet jammed into the case that looked like the nose of a Mig-19.  Happend when a case didn't extract but the bolt stripped the next case off and rammed it quite nicely into the chambered case in front.  Factory crimp didn't stop that bullet from setting WAY back.  Had I not noticed it and shoved that round back in the mag it would have been a bad day.  Very bad day.

No reason to be reckless but I'm not in fear either.  I did buy a crimp die after seeing this thread.  Seems like a prudent step to help reduce the risk a bit.

I'll not argue his observations or his opinions.  Evaluate the risk and make your call.

My $0.02

Reloading centerfire ammo is demanding and exacting.  Loading a 223 to 5.56 specs is probably the most difficult round to load and load safely.  Working pressures are in the neighborhood of 50,000 psi, and that is a very dangerous neighborhood to hang out in.

This KB was the result of pressure far in excess of the proof loads used by the military in its milspec aceptance preceedures.  The pressures involved are in excess of design load as demonstrated by the failure of brass and extractor.  If this were a life safety piece of equipment subject to a continuing certification and inspection program, this incident would cause the item (rifle) to be removed from service and inspected and possibly scrapped for being stressed beyond specs.

Mention was made of not seeing advice about crimping, etc. in several reloading manuals.  I am positive EVERY manual says to constantly check for signs of high pressure.  If a reloader doesn't know the signs of high pressure for the round/gun he is loading for, more study is required before any more rounds are loaded.

Do I know everything  about reloading?  Hell no.  But I do know a littla about the AR and reloads.  I also know factory ammo can be bought for 10 cents a round, so one needs a really good reason to reload for this round.

I am trying to shake up anyone that is complacent about this subject.  It is always safer to learn from other's mistakes, and rest assured ALL these failures have happened to someone else already.

Stay safe, guys.  We are all on the same team.

Quoted: Reloading centerfire ammo is demanding and exacting.  Loading a 223 to 5.56 specs is probably the most difficult round to load and load safely.  Working pressures are in the neighborhood of 50,000 psi, and that is a very dangerous neighborhood to hang out in. This KB was the result of pressure far in excess of the proof loads used by the military in its milspec aceptance preceedures.  The pressures involved are in excess of design load as demonstrated by the failure of brass and extractor.  If this were a life safety piece of equipment subject to a continuing certification and inspection program, this incident would cause the item (rifle) to be removed from service and inspected and possibly scrapped for being stressed beyond specs. Mention was made of not seeing advice about crimping, etc. in several reloading manuals.  I am positive EVERY manual says to constantly check for signs of high pressure.  If a reloader doesn't know the signs of high pressure for the round/gun he is loading for, more study is required before any more rounds are loaded. Do I know everything  about reloading?  Hell no.  But I do know a littla about the AR and reloads.  I also know factory ammo can be bought for 10 cents a round, so one needs a really good reason to reload for this round. I am trying to shake up anyone that is complacent about this subject.  It is always safer to learn from other's mistakes, and rest assured ALL these failures have happened to someone else already. Stay safe, guys.  We are all on the same team.

I absolutely agree with everything said above.  Complacency breeds inattention and shortcutting.  It never hurts (figuratively) to get the occasional slap in the face and reality check.  Our poster got away lucky here and hopefully it makes an impression on him.

Norwester I don't think it's been mentioned here yet but the info in blue above is important.  You probably should have the rifle checked even if it does seem function still.  I'd rather err on the side of caution here if I were you.

thanks for the steer Tweak...

What kind of additional checklists do you need. Every AR manufacturer warns not to use reloads in their products. And most (if not all) state there is no warranty coverage due to damage from reloads.  SOP for reloading ammo for semi-auto weapons is heavy crimp and cannelure. Crimped primers are also recommended.

actually, i was not referring to reloads with regards to my comment on a "checklist".  what i was thinking was more along the line of "signs" of overpressure that one might otherwise not really notice like the indententions in the cases that are shown herein by the picture posts.  

the one i posted showed an overpressure condition obviously, and the rifle was probably doing it for many months, if not years.  my mistake for not noticing it and not really worry about things until the bolt busted.   that was the wake-up call that got me looking for signs of overpressure.  had i known enough about the topic prior to, it would have been a good thing...

btw - i use only factory ammo.

I've always kept my handloading to my bolt-action rifles.  The reason's pretty simple - there's a lot less going on!  Not that loading for a military or other semi-auto can't be done, certainly it can.

Again there are lots of causes for overpressure.

Mention was made of not seeing advice about crimping, etc. in several reloading manuals. I am positive EVERY manual says to constantly check for signs of high pressure. If a reloader doesn't know the signs of high pressure for the round/gun he is loading for, more study is required before any more rounds are loaded.

Well uh, thanks for that,even though what I mentioned and the fact that the manuals..I'll leave that alone. I'm thinking this is all a matter of opinion between'st those that do and those that don't. You'r correct of course that all reloaders should take due precautions and follow procedure. And unless I'm wrong,that would be the big end of that screwdriver that you hang on to. Happy to help out!

Burnsome,
some of the "classic" over pressure signs are generally primer indications. The problem with that is that those signs can appear when an overpressure situation isn't present and can also NOT appear when one is. A flattened primer can occur because of excessive headspace. A cratered primer can be and most often is due to a firing pin problem. Sloppy primer pockets are another,one of the better indicators, but if you don't reload,that wouldn't apply. If a primer flattens to the extent that its curved edges completely disappear and it looks to be filling the primer cup...well then you just might be(assume you are) over pressure! Brass indications such as the ejector marks already noted,case head expansion (CHE) which  though employed by a few noted authors on the subject is an iffy proposition to say the least. I'v ran into a couple cartridge/rifle combos that didn't expand any more than a factory load even at what was known to be excessively over pressure.In bolt action rifles"sticky" bolts and in revolvers,sticky brass extraction,I'v found to be very reliable but doesn't really apply to semi autos unless the case is stuck and/or your extractor has ripped the rim off. The problem with all of the above is that none of the signs appear until you're WAY overpressure! IMO the most important tool for a reloader  is a chronograph. Simply put, do not exceed book velocity! I suppose you could find out what your factory ammo is clocked at and if you'r exceeding that excessively, know you may have issues with your rifle? I have ran across a bad box of factory ammo once that was loaded well over max, but I'd think with all the fear of lawsuits, it would be pretty unusual.  There are cheap but reliable chronographs out there such as "Shooting Chronys" for $50-60 I think. ar-wrench is correct to be concerned about stress and if you'r shooting overly warm loads the stress is cumulative and in time most likely something will give,in your case the bolt. Heres a site that goes into case conditions a bit.
www.reloadingpro.com/Case%20Conditions.htm

thanks norwester.....that link is excellent and just what i was looking for sir...