Polymer guns CAN handle kaboom!

[mike445]

I have an M&P 45 I’ve put several thousand rounds through. Yesterday at the range one of my friend’s reloads went kaboom blowing the magazine out of the gun. He was shaken up a bit but he was okay. So was the gun after I put the magazine back together. I ran another 40 rounds through the gun without issue. I know there wasn’t a double load because All reloads we build are weighed after we build them for consistency. Any ideas? I’m thinking weak casing.

 

[Trinimon]

Reloaded a resized brass that was shot from an unsupported chamber that had already been weakened from earlier shootings?

 

[roadcarver]

Was it a range pickup brass?

 

[colinjw]

Reloaded a resized brass that was shot from an unsupported chamber that had already been weakened from earlier shootings?

Seems to be the likely cause.

 

[mike445]

Reloaded a resized brass that was shot from an unsupported chamber that had already been weakened from earlier shootings?

Yes that’s what I’m thinking too.

Was it a range pickup brass?

It very likely was. If anyone is shooting 45 I ask if I can grab the brass.

Mike C.

 

[mike445]

Seems to be the likely cause.

Thank you. Now the question is how do I avoid this in the future? Are there signs I can look for on the casing?
Mike C.

 

[Canuck44]

Double charge. You doubled up a case. 45acp is a low pressure round. Double charges will tear a case apart just like the one you took a picture of. No method of reloading is fail safe. You simply missed one.

Take Care

Bob

 

[mike445]

Double charge. You doubled up a case. 45acp is a low pressure round. Double charges will tear a case apart just like the one you took a picture of. No method of reloading is fail safe. You simply missed one.

Take Care

Bob

I am second guessing a bit. We do weigh every reload to make sure they are all within a grain but it’s possible one slipped through. As you say. No method of reloading is fail safe. It’s not going discourage myself or my friend from reloading. Thank you for the input. Everyone has been so helpful. I appreciate it.
Mike C.

 

[Canuck44]

Mike I have had two, both 45acp. The first was 10 years ago...I changed how I reloaded using my 550 press. The next about six years ago...I made another change and have had none since. They say to error is human and that seems fair enough. I think we all, depending on the extent of our egos, have a tendency to assume we have all the bases covered and our system is fool proof. I figured I had be doing it for so long, how could I ever make a mistake...I did. You may have convinced yourself by checking each and every load there was no way a double charge could get by you....it did. Learn and move on. Glad nobody got hurt. Great hobby just comes with a few risks. :>).

Take Care

Bob

 

[mike445]

Mike I have had two, both 45acp. The first was 10 years ago...I changed how I reloaded using my 550 press. The next about six years ago...I made another change and have had none since. They say to error is human and that seems fair enough. I think we all, depending on the extent of our egos, have a tendency to assume we have all the bases covered and our system is fool proof. I figured I had be doing it for so long, how could I ever make a mistake...I did. You may have convinced yourself by checking each and every load there was no way a double charge could get by you....it did. Learn and move on. Glad nobody got hurt. Great hobby just comes with a few risks. :>).

Take Care

Bob

Thank you Bob. You are correct. Everyone and the gun is ok. This is a good learning experience that I hope never happens again. This is an amazing hobby. Have a fantastic weekend!!
Mike C.

 

[Cameron SS]

Based on the photo, i would also suggest double charge. Blowout looks like it originated at the flash hole and blew out the back of the case. Most case failures where the case is the culprit is at the side wall.

In an all explosions the pressure wants to escape via the path of least resistance right? In an overpressure condition, the sidewalls are pushed outwards into the chamber with such force that the case does not extract when it normally would, leaving the only avenue of escape to be to push back through the primer onto the face of the slide, which by design, will yield under pressure. One the slide is moving, the volume of available space for the overpressure gas will increase, resulting in a decrease in pressure, and probably the case contracting and letting go of the chamber.

What was the extraction like?

If you are inclined to think that this was a weak case, then I would want to remove all of the cases of similar origin from circulation, just to be safe.

 

[Scarheart]

Another possibility is that the brass was used several times and hardened. Brass is one of those metals that work hardens. That's why shouldered cases often need to be annealed to extend the life of the case. Since there isn't a lot of case stretching on straight walled cases it's easy to forget that the case is still work hardening every time it's shot.

 

[Trinimon]

Very well could have been a double charge as others suggested.

Good news is that nobody was injured. Anytime I have to raise the ram more than once even if it is a partial raise, whatever case is the the powder stage gets dumped.

If the brass looks anything like this pic, toss 'em.

 

[JoKa]

I have reloaded brass to the point that the nickel is worn off it and the headstamp is hard to read. All I have ever seen is split cases. Never a failure like that from weaken brass. That is a blow out.

 

[mike445]

Based on the photo, i would also suggest double charge. Blowout looks like it originated at the flash hole and blew out the back of the case. Most case failures where the case is the culprit is at the side wall.

In an all explosions the pressure wants to escape via the path of least resistance right? In an overpressure condition, the sidewalls are pushed outwards into the chamber with such force that the case does not extract when it normally would, leaving the only avenue of escape to be to push back through the primer onto the face of the slide, which by design, will yield under pressure. One the slide is moving, the volume of available space for the overpressure gas will increase, resulting in a decrease in pressure, and probably the case contracting and letting go of the chamber.

What was the extraction like?

If you are inclined to think that this was a weak case, then I would want to remove all of the cases of similar origin from circulation, just to be safe.

Thank you! That’s All Great info. It’s looking more like a double charge. Extraction wasn’t a problem. The round fired and the case extracted in pieces. The magazine ejected out of the bottom and in pieces. I put it all back together and all was good. Have a great weekend.
Mike C.

 

[mike445]

Another possibility is that the brass was used several times and hardened. Brass is one of those metals that work hardens. That's why shouldered cases often need to be annealed to extend the life of the case. Since there isn't a lot of case stretching on straight walled cases it's easy to forget that the case is still work hardening every time it's shot.

Thank you for your input. This case has only been fired once before this happened. How many times is acceptable with 45 ACP for reloading the brass?
Mike C.

 

[mike445]

I have reloaded brass to the point that the nickel is worn off it and the headstamp is hard to read. All I have ever seen is split cases. Never a failure like that from weaken brass. That is a blow out.

Thank you.
Mike C.

 

[Cameron SS]

Thank you! That’s All Great info. It’s looking more like a double charge. Extraction wasn’t a problem. The round fired and the case extracted in pieces. The magazine ejected out of the bottom and in pieces. I put it all back together and all was good. Have a great weekend.
Mike C.

I have seen more than a few case failures that did not cause the other signs of overpressure, typically mag blow out. I'd be pretty confident its a double charge.

Question about your weighing to verify that there isn't a double charge. How many grains of powder are you using? I don't reload much pistol, but my understanding is you typically aren't using more than 4 of 5 grains of powder, yes?

Have you measured your empty cases to confirm that the variance in cases alone can't be greater than this? Individual lots are fairly consistent, but between different brands I have more than once seen a variance in case weight greater than 5 grains.

It would seem to be that it is entirely possible that a double charge in a light case might go unnoticed.

 

[Tractorguy]

One of the shooters on VSO YouTube channel had that problem, but it blew his M &P 9 to peices. They later found that the M&P line can drop the firing pin dispite not being in full/complete battery (plus or minus a thousand) causing all back pressure to be channeled down mag well. Unfortunate for him, the firearm was destroyed. The ammo in question was steel cased Wolf, which I believe would be charged a little lower than other factory to keep costs down. But can only speculate on your insistent.

 

[Canuck44]

Thank you for your input. This case has only been fired once before this happened. How many times is acceptable with 45 ACP for reloading the brass?
Mike C.

Mike I tested this and quit counting after reloading a Win case 16 times. I have also had Norinco 4acp brass split after one reloading. The Norinco brass appears to be on the harder side as it typically splits with less reloads for me. Nickle brass tends to split much earlier than copper brass due to the hardness of the nickle coating I presume. Side splits have never presented a problem. I never know about them until I pick up the brass and notice the split.

Take Care

Bob