Possibly too much unsupported case protrusion or chamfer at the back of the chamber?
Case head Separation…in Sizing die
- Thread starter T.Rhodes
- Start date
Die and chamber mismatch and repeated sizing?
BTW, ever clean your brass?
BTW, ever clean your brass?
Well, right now I've got about 120 cases to sacrifice...I have no confidence in them.
Is this a factory rifle or custom bbl? Pics of the chamber end of the bbl might be of help. As I mentioned before, it might be a gun problem rather than a brass or die problem. A little info on the build might get us on the right path. Where your case separated is not typical for an incipient separation but is of a case that has too little support at the back end and it's not as rare as you might think.
Here's just one discussion of several on it fwiw
Why Deep Chamfer on Barrel Chamber?
That chamfer is a good .040 deep A PPC case is solid for about .150. This is off of a Panda. On these, there is .135 case protrusion plus bolt to bbl clearance. Kelblys tenon print allows .007-.010 for this clearance and at that, it would have .145 unsupported case protrusion..all solid. This...
forum.accurateshooter.com
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I have. It was the result of a die that was oversizing my brass. I didn't have a tool to remove it form my chamber, it was a range session ender ...
Because it could damage the rifle or YOU.
10 reloads with a 0.002 inch shoulder bump is 0.020 inch total. Add that together with some radial squeeze at the bottom of the case.
This is a stock Bergara action with a new 30" 7 1/2 twist Proof barrel in heavy palma contour. I'm sure it was chambered by a competent smith. I sent him fired and sized cases to work from.
After I got it back, I did start with loads that were too heavy... 41.0gr of H4350 and Berger 153.5gr Hybrids and was getting 2750fps or so (accuracy sucked). This may have likely damaged brass. The load that has been the best is 37.5gr H4350 with the 153.5's and getting velocity of 2605fps.
Can you explain how it could damage you?
Murray Brook
Silver $$ Contributor
Hot gasses could be vented in your face. Chamber could be cut by the hot gases ruining your barrel, and there is Murphy.
I wouldn't call that crazy hot. It might be a brass issue but honestly, I have my doubts based on everything said to this point. I've gone 50+ firings with way higher pressures, just for reference only. Lots of good info from several posters in the thread I linked, and there are several others on here, on the same subject. Competent and perfect are not the same thing. I'm very competent in this but I've also made a few mistakes in 25 years, so I know it happens.
It's totally up to you how you proceed but I will just say that I would not expect it to be only brass related. You did come here, presumably looking for feedback on your issue. Why did it fail in that location? Do this for yourself...measure a case oal and then measure the depth to the base inside. Subtract the depth from the overall. That's the solid portion depth. Now, if possible, measure the case protrusion from the chamber and add bolt nose clearance, call it .010 if you don't have a good way of checking it. Now compare where your case failed to that number. .150ish? Maybe a tad more?
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swd
Silver $$ Contributor
I have and it’s not any fun. Lots of gas and crap in your face. And while the shooter is far more important than the gun it ain’t exactly good for the gun either..
swd
Silver $$ Contributor
How many firings do you have on that brass and is it all in the same barrel?
I would pull the barrel and like Mike mentioned check how much unsupported case it has. My strong guess would be either brass that has been over worked at the back end and/or unsupported case or a combination of both.
The back of the chamber may be oversized causing your die to over work case head area.
And I’d toss all that brass after you get it figured out.
I would pull the barrel and like Mike mentioned check how much unsupported case it has. My strong guess would be either brass that has been over worked at the back end and/or unsupported case or a combination of both.
The back of the chamber may be oversized causing your die to over work case head area.
And I’d toss all that brass after you get it figured out.
painter
Gold $$ Contributor
I did that with a grey scotch bright pad that showed where it was thinning with a visible line
The reason I ask if anyone ever had one is I wanted to know what they experienced when it happened. I had it happen on a 300 Rum but it didn’t harm anything. Matter of fact, the only thing I noticed was when I pulled the bolt back to pull the round out after I fired, only part of the case came out. It’s not a over pressure round or anything. Probably some gas came out the hole in the side of the action but I don’t even remember. And yes, it’s not a desirable thing to happen and I’m not belittling when it does happen, just that I personally don’t think it’s a life or death matter. In my case, I believe I know why it happened. I had set the fl die to resize the brass in the state it was in when I got it, it had already been fired I don’t know how many times, not by me. Then I annealed them and resized. After that case separation, I checked some of the others and they were way short, I don’t remember how much exactly, maybe something to the tune of .010-.020 short. This was on a 700 action, maybe some others would be more dangerous, I dunno.
This thread is worthy of study:
Request of all you experienced belted case loaders
Often when one guy tells a new loader something, with all of the sometimes contradictory information on the internet including YouTube, it is hard for him to decide who to believe. What I am looking to get here is multiple source that will by their volume reinforce a point that needs to me made...
forum.accurateshooter.com
The barrel has just over 700 rounds through it; the OEM barrel had over 2K rounds before replacement. And the cases - as stated - have not been tracked. That is my failure.
This is only the second case head separation I've seen so I can't say if that is typical or atypical. The thinning does appear very similar to the photos HERE . The text indicates the thinning is caused by repeated full length sizing that draws the case body longer with the resizing.
Gut feel on this is, it's due to my reloading/sizing process (full length every time).
This is only the second case head separation I've seen so I can't say if that is typical or atypical. The thinning does appear very similar to the photos HERE . The text indicates the thinning is caused by repeated full length sizing that draws the case body longer with the resizing.
Gut feel on this is, it's due to my reloading/sizing process (full length every time).
Thinking the reason it is as low as it it on that brass, in looking at the cutaway, that part of the issue is the design of the web itself, seems to me it is a fairly short, sharp radius inside compared to other brands, which as I remember seeing are longer radii on them, which usually shows separation rings higher up on the case.
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