Does this sound like a case head separation?

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distra

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I picked up a G22 .40S&W over the summer and have been shooting it every weekend in IDPA matches. I reload the .40S&W and have been all along. I had something strange and scary happen at today's match. Half way through the 3rd stage I pulled the trigger and immediately felt a sting on the inside of my right hand. I looked down and the magazine had been blown out the bottom of the gun and a piece of the magazine release fell onto the ground. I was not cut or hurt except for my pride due to my shooting buds thinking it was a double charge. I don't think it was a double charge since 2x the powder will not fit into the case. The report and recoil felt a little weak. I'm wondering if this is a case head separation. I had one case in this batch of brass that showed cracking and separation. I'm not sure if this is how the gun would react to a case head separation and thoughts? The load used was 4.5gr of Red Dot (max in Alliant manual is 5.1gr) behind a 170gr round nose bullet.
 
Sure sounds like a case-head separation. AKA Ka-BOOM. A previously bulged case was resized possibly but the stressed portion of the case ended up at the 6 o'clock position in an unsupported or inadequately supported chamber, i.e. over the feedramp. Luckily you weren't hurt.;)
 
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I pulled the trigger and immediately felt a sting on the inside of my right hand. I looked down and the magazine had been blown out the bottom of the gun and a piece of the magazine release fell onto the ground.
Yup, sounds like a classic Glock KB (case base fails and escaping gas blows out the magazine and mag release/internal parts also get damaged).

The load used was 4.5gr of Red Dot (max in Alliant manual is 5.1gr) behind a 170gr round nose bullet.
Alliant's website currently don't list Red Dot for 40S&W. It doesn't matter whether your load was mid range or near max. The case base failure could occur from weakening of brass with repeated bulging and resizing of the case or other factors.

Even though you are careful about your reloads and use mid-range load which may not bulge the case, if you pickup range brass, you could have picked up someone else's brass that's been over-stressed or reloaded enough times with bulge/resize cycles to weaken the brass.

I pick up range brass and this is the reason why I use Lone Wolf barrels in my Glocks. Case base support is better than any other factory barrels I have seen and the tight chamber minimizes the case expansion to the point that my high range 40S&W loads take hardly any effort to resize. Spent case walls are very straight.
 
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Thanks for the replies. I thought this was the issue. I've ordered the Lone Wolf barrel for the G22 and my Alliant manual is from '05 so I think I'll change to Unique. Hopefully these changes will prevent this from happening in the future. I love shooting the G22 and generally place quite high in the standings with it. Too bad Glock has not addressed this directly. Can't afford to shoot factory loads every weekend and at practice.
 
Too bad Glock has not addressed this directly.
How old a G22 we talking here? Glock tightened up their chambers years ago. I shoot at the local FOP range, and noticed the brass these days, don't have the "Glock belly" anymore, so they did address the issue:cool:
 
The G22 is refinished Gen 3 that came with mag pouch and holster (competing with the XD gear). I'm sure they tightened the chamber, but the brass I have is from range pickup so the case could have been compromised before I loaded. I try to inspect all the brass, but I guess I will need to look a little closer. Of course it's highly possible I would not have been able to see the defect. I compared the Glock chamber to my M&P40 and there is a significant difference in case support. The M&P has support all the way where even the tightened chamber Glock does not have full support. I guess Glock did address the issue by providing more support than previous versions and I must say it took the case head separation pretty well with only damage to a $3.00 mag catch and most important no injuries to me.
 
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Early gen 3s, had the looser chamber. How does the brass you fire look? Bullet setback on an otherwise safe load could cause a KB. Glad you weren't hurt, and Glocks are pretty tough, chances are the gun is fine too.
 
That's the problem, I was so focussed on my hand that I racked the slide to show clear and the fired case fell in the snow and was not recovered. Glock are tough that's for sure.
 
How does any brass you fire look? Not just the one that KBed, we know how that one looks. If your brass doesn't have the belly, or feed ramp half circle bump, your barrel is probably just fine. If your wanting to shoot lead, an aftermarket barrel may be the answer, but I shoot with a guy who shoots lead from his factory barrel without issues.
 
The brass looks fine, but most do have a slightly bulged area at the case head. Nothing major. You can see where the sizing stops and case has expanded farther down the case.
 
distra, you might want to see this thread also. http://www.thehighroad.org/showthread.php?t=566966&page=2 as your situation has been discussed. I think you are already on the right track with your future use of a slower powder. For full power loads with jacketed bullets I would recommend that you try Ramshot Silhouette as I believe it is the original .40 S&W powder as it was known then as WAP or Winchester Action Pistol. It delivers fine accuracy. For cast loads that are slightly less than max. or medium loads you might want to try Ramshot True Blue as it delivers excellent accuracy in .40 S&W loads. Either powder is slower than Unique.;)
 
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