SNAFU 5.56 reload

[xerts1911]

Sooo today at the old range, shooting the AR, box of reloads mixed brass some are LC the others are CBC. I do not recall ever buying the CBC brand either brass or ammo? Anywhoo, about 20 rounds into the shooting festivities, the BCG hung up in battery, a wtf moment, dropped the magazine, rounds that were left in it looked good. Had to get physical with the old carbine to get the BCG freed up, when I got it locked back again I could see a live round still in the chamber, it wouldn’t fall out like I wanted it to, I wanted to see if the round would fire, knowing damned well the BCG would likely hang up again, got the round to fire, BCG gave me another round of wrestling to get it locked back again. When I did get it locked back could see spent case stuck in there, banged it around a bit to see if it would fall out, no Bueno. When I got back to the casa de xerts I dumped some lube down the barrel and put the old cleaning rod down her gullet, couple of raps with the rubber mallet knocked it out. Chunk of the case rim had busted. Maybe the case rim break was on the extractor side?
Have you all ever had any problem with CBC ammo or brass, I don’t have a clue as to when or where I got it, I still have some of this brass currently reloaded, got the magnifying glass out to look them over, they appear to be kosher :shock:
Anyway, sh!t that makes me go hmmm

 

[xerts1911]

I knew you wouldn’t be able to resist

 

[QuietM4]

I don't know what's worse...the grammar and syntax of that post of the accompanying blurry photo.

 

[Suck My Glock]

When I used to occasionally encounter this with my reloads, I also used to think that it was a failure of the brass and that some brass was better than others. But eventually, I saw it happen with even "the good brass" I had determined was less likely to fail.

It wasn't until years later, after reading a large scale testing LUCKY GUNNER did with .223 ammo trying to determine if steel cased ammo was bad for ARs or not, that I discovered (or rather, Lucky Gunner discovered) that rim failures like this have more to do with inappropriate powder burn rate for the application than supposedly "weak" cases.

Primary example was factory TULA .223 ammo was repeatedly suffering from this exact same type of rim failure, despite being steel and factory fresh. After dissecting the ammo and testing components of it, they eventually realized that TULA's powder had a significantly different pressure curve that used by most Western manufacturers. When combined with other factors, such as "extractor lift", the inappropriate burn rate and corresponding pressure curve timing would conspire to see the extractor not be fully enclosed over the rim and have only a partial grasp. And thus, when finally pulling on that rim without a full hold of it,...off comes the material.

I started using powders from within the advertised approved burn rate range which were slightly slower and therefor producing a longer pressure curve. CFE223 is one of the slower ones, as well as Varget and TAC. Likewise, if you check where surplus 844 military powder falls on the chart, it too is on the slower end for this round. Once I started using these powders, I stopped having rim failures almost completely.

I had previously been a fan of AA#2230 and used this powder for 20 years. I liked that it was originally an Israeli formulation with flash suppression additives. It also metered well due to being a spherical ball powder. The Israelis seemed to always make good schit, so I took it on faith this powder was golden. But when checked against the burn rates of the other recommended powders for this cartridge, it turns out to be among the fastest. I no longer use it.

 

[Gatsby]

Those were both excellent replies.

SMG: thanks for that summary. This winter I was going to experiment with faster powders for my 10-1/2" but this made me re-evaluate. I wouldn't want to trade reliability for a few FPS.

There is nothing inherently wrong with CBC brass; I reload it without any more problems than any other. CBC makes (I believe) Magtech as well. One thing I'd like to add though: if you've never bought any then it's possible it was picked up by accident at the range, and you don't know the history of the brass. It may have been left because it was on the 87th reload.

 

[knockonit]

lol, post natzis, funny chiat, patience is key to reading many posts mostly mine. lol
RJ

 

[Flash]

I'm curious.

Where does one find the "advertised approved burn rate range" chart that's mentioned? I've never seen anything like that.

 

[delta6]

Here is one...

 

[Gatsby]

There’s an IMR one that I found and bookmarked, and it looks to be all (or at least most) manufacturers

 

[xerts1191]

I’m going with crappy brass theory

 

[Flash]

Here is one...
burnratechartnew.jpg

No, that's a powder burn rate chart, it's not an "advertised approved burn rate range" for a given cartridge that was posted above.

 

[Remow2112]

Badly resized brass. I have never torn a rim off 223 but I have had a couple that were really abused. Went through a spot where I was getting rounds jammed just enough out of battery to not fire. Worked fine in my other ARs but not in my Ruger MPR. Discover that the MPR has a tight chamber and I got a case gauge and started checking some of my loads. Sure enough some are sitting a hair high in the case gauge.

Another interesting note, when I was messing with this I bought a box of Federal 5.56 to check against. Factory brass is a good couple thousands undersized. At least in the case of the Federal 5.56.

 

[Suck My Glock]

Here is one...
burnratechartnew.jpg

No, that's a powder burn rate chart, it's not an "advertised approved burn rate range" for a given cartridge that was posted above.

Ok,...perhaps I should amend my language. When I said that, what I was referring to was the range of powders you will find loading manuals used for this cartridge. Whether you refer to factory sheets from the powder manufacturers themselves or manuals from bullet manufacturers like Sierra;...when looking at the section for .223/5.56, there tends to be only a handful of powders used for this round, and that is due to where they fall on the larger burn rate chart for all powders. Any handloader worth their salt always has on hand the burn rate chart to refer to. So,...when I say the chart of burn range for powders for this cartridge,...I mean the chart within the larger chart,...which one discerns for themselves from the data. Within the larger chart, H335 is the faster end of the .223 spectrum, and CFE223 is the opposite.

 

[Flash]

Okay, I see what you mean now. H335 isn't the fastest usable by any means, and burn rate mostly depends on the weight of the bullet itself, so there is a lot to it. A friend and I both use H4198 for 55 grain bullets, and it's a lot faster than 335 but works extremely well.

I carry a powder burn rate chart in my cellphone and update it to the latest version every 6 months or so and find it very useful to have with me.

 

[Remow2112]

I have been using AA2200 DP for years. It is the predecessor to AA2200. It is pretty fast burn rate but has worked very well for me.

 

[Old Jeff H]

Case gauges are nice for letting you know there's a pretty good chance your loaded round is going to chamber, but they don't tell the complete story. For bottle neck cartridges, I put my trust in a true headspace gauge like the Hornady Comparator or the RCBS Precision Mic.

In another thread I described how my Lyman gauge was leading me to push the shoulder back 10-12 thousandths beyond SAAMI spec. The ammo functioned fine, and was plenty accurate, but I was getting flattened primers even at minimum charges.

Shoulders getting pushed backwards and shoved forwards +/- ~15 thousandths sure isn't a good thing for brass life either.

 

[xerts1191]

Thanks Jeff H. I’ll check on a headspace Guage

 

[xerts1191]

Those were both excellent replies.

SMG: thanks for that summary. This winter I was going to experiment with faster powders for my 10-1/2" but this made me re-evaluate. I wouldn't want to trade reliability for a few FPS.

There is nothing inherently wrong with CBC brass; I reload it without any more problems than any other. CBC makes (I believe) Magtech as well. One thing I'd like to add though: if you've never bought any then it's possible it was picked up by accident at the range, and you don't know the history of the brass. It may have been left because it was on the 87th reload.

I believe you may be correct Gatsby

 

[xerts1911]

https://www.thearmorylife.com/levar-review-the-ultimate-ar-malfunction-buster/
One of these might have come in handy a couple of weeks ago?