.223 primer pocket blowout

[NFATrustGuy]

I must've messed up somehow… I'll just admit that from the outset.

I've got a CZ527 bolt action .223. A friend invited me out to his farm to shoot rabbits this morning. I took exactly one shot with my .223 and my long(er) range day was over. The one shot seemed to have a bit more bang than I'm used to feeling with a 223 and then the bolt was stuck in the closed position with a spent round in the chamber. I removed the magazine and tried harder to open the bolt. Still not going.

We ended up shooting my CZ 455 .22LR with the suppressor the rest of the day, but I gave up on the .223 until this evening when I could mess with it at home. I ended up getting the bolt open by tapping on it with a small block of wood. It actually didn't take too much tapping or too much force. The bolt now operates normally.

Here are a few pictures of the spent shell casing and the primer as they were ejected this evening on my workbench:

http://www.woodardfamily.com/hosted/primerpocket.jpg

http://www.woodardfamily.com/hosted/casewprimer.jpg

Did I somehow manage to overcharge the round? Is this a sign of the brass failing due to overuse? Is this what happens if you use brass that's been reloaded more than XX times?

The load is a Nosler 40gr orange tipped bullet with 23.0 grains of H322 with a CCI small rifle primer.

http://www.woodardfamily.com/hosted/40grNosler.jpg

[vossman]

Wow, glad nobody was hurt. Were the primers magnum primers?

[NFATrustGuy]

Wow, glad nobody was hurt. Were the primers magnum primers?

Nope. Just regular 'ol CCI-400 Small Rifle Primers.

I'm really lucky I wasn't hurt. I swear this was the first time I ever fired a gun without eye protection. I figured it was just me (i.e. nobody else to worry about at a range) and it was a bolt action so I didn't need to worry about cases being ejected and thrown around like a semi-auto does. The gun seemed to recoil a bit stronger than I remember and I think I got popped just below my eye with a flip-up scope cover. I have two little mosquito bite sized scrapes about 1/4" below my eye--right in the part that's always puffy when I don't get enough rest.

I'm still hoping somebody will offer an opinion as to whether this was a failure with the brass or if I somehow managed to over-charge the round.

To cap off the day, I think it was the first time I've visited my buddy's place when I wasn't practically tripping over rabbits running around. I don't know where they went, but they weren't anywhere near where I was!

RWW

[KS63]

Looks like case head/rim failure to me. Others with more experience will chime in.

[XC700116]

The potential is there with H322 to grossly overcharge a 223 case with a 40 gr bullet. What I mean by that is unlike something like Varget where with a 40 gr you're not going to be able to cram enough in the case to do that kind of damage, there's plenty of room to do it with H322. I'd pull a bunch of those bullets and check the charge in them from when you loaded that batch to make sure you didn't accidentally overcharge the whole lot.

Outside of that it's pretty hard to tell, but it looks like a nasty overcharge to me. I'd also inspect the bolt face closely to make sure there's no damage.

I assume this is a load you've worked up in that rifle correct? If not, that's the first sign of what happened.

[brutal]

With the way that primer looks cupped, I'd say overcharge. Could also be a very loose primer pocket too I suppose. Limited experience on this side of the keyboard so I can't say for certain if a loose primer pocket would have a blowout like that.

[Great-Kazoo]

23 is low end of data for the bullet and powder.OP didn't mention or i missed what the OAL was? Data says 2.280 all from Hodgdons site

Nosler shows 23 is low end with a 2.260 OAL. It could be the case OR seated too long at the suggested spec hitting the lands?? Do another one w/out primer & powder at the OAL used and see if it's hitting the lands. Use some majic marker on the bullet

[KS63]

If CZ's rifles are like their pistols, they have short leades. Do what GK suggested or, even better, use that Hornady chamber checker thingy with the modified case and your bullets.

[Hoser]

Without a doubt, too much powder or a powder mix-up.

You are lucky. I know lots of guy that never shoot with eye pro and don't think a thing about it.

[MarkCO]

Without a doubt, too much powder or a powder mix-up.

You are lucky. I know lots of guy that never shoot with eye pro and don't think a thing about it.

Yep, that is a gross overpressure. However, i strongly doubt an overcharge with H322. I have purposely overcharged .223 by a good margin, like filled to the brim and then compressed the load, with a bunch of powders including H322 and you don't get damage from one shot. It is more likely that you had a powder mix up or the bullet got pressed into the case past the ogive. I've blown up a good number of guns on purpose for various tests and cases and you just can't get that kind of pressure from H322 with a normal OAL. It takes about 2x to blow out the side of the primer pocket on a .223 case.

[NFATrustGuy]

I just took a random sample from the 49 cartridges remaining in the box of 50. It looks like my OAL is 2.255 to 2.260 so I think I'm within tolerances. I also looked up the suggested loads from the Nosler website and I'm at the low end of the three loads they publish.

According to Nosler, a .223 case is capable of holding 29.2 grains maximum. If I somehow managed to fill that one particular round to the brim, I'd be approximately 12.3% over Nosler's maximum published load for H322. I'm not saying it couldn't happen, but with a Dillon 650 and a powder checker on Stage 3, it seems unlikely.

After this experience, I vow to **never** pull the trigger in anything short of a self defense situation without eye protection.

I've probably fired 150 rounds of this same load through this rifle with no issues in the past. It was actually VERY accurate producing sub-MOA results at 100yds.

Next step: I've got some machinists blue dye that I'll paint on a few rounds to check the chamber/lands fit as the Great One suggested. In the meantime, here's a screenshot of the data from Nosler's site.

http://www.woodardfamily.com/hosted/noslerload.jpg

http://www.woodardfamily.com/hosted/nosleroal.jpg

[Zombie Steve]

The only thing I haven't seen mentioned here is you could be pushing the shoulder too far when sizing. If there's too much room and the primer can back out enough, the boom can go the other direction. It could be a combination of that and a loose primer pocket. Easy check with a case gauge.

[MarkCO]

The shortened OAL can come from chambering with not enough case neck tension. Dirty or tight chambers can exacerbate this.

[legaleagle]

It is also possible that there may have been too little powder. I have seen this happen first hand. What occurs is the powder shifts to front of case as you bring gun up and muzzle is down. The primer goes off and dislodges the bullet into the lands or slightly further. With bullet stuck the powder then ignites in a delayed reaction, but so minute you don't think of it as a hang fire. Alas, ignition of powder creates massive pressure as bullet is essentially stuck in barrel. Often the gun blows up. Saw this with a gorgeous British 303. The load was confirmed a light load as it was loaded on purpose that way. The bolt went out the back of the tub and removed shooter ear and made bloody mess. Bolt went about 50 feet. Chamber ruptured and split receiver too.

As as I recall, the late Wayne faatz, who I learned this from wrote an aricle about it. I believe it is referred to as the expansion effect.

In in addition to other suggestions, I would micrometer the bullets too. Start eliminating variables. Also, I have seen a lot of brass from semi 223/5.56 that has pulled the rim up slightly. This make weaken the rim area of the case.
Also, I have had head separation especially with full length resize, but this is not the same. I would look at brass and find similar head stamp and measure internal case volume. I ran across some brass that had a step on the inside causing reduced volume. Create a similar effect to between mil brass and commercial.

in your picture the flash hole looks like it is too big. This blow out too? Not sure if too big a flash hole would cause an issue though.