Bad Day at the range

[DCART]

The pictures shows what happened after shooting about 40 rounds through my XDM 40 last Thursday. A tech at Springfield said, because they were reloads, that the base must have separated due to a weak case. Sure looks like it fired out of battery since the nickel plated brass is shaped to conform to the ramp and breech.

[tpetaja]

I have had this happen twice and the out of battery part, I can believe. I did a check on mind, and I could not get it to fire, out of battery.
Anyway, here is what I believe happen to me. My type of powder I was using, was fast burning and hard to meter. I must likely had overcharged round and also, I was setting my OAL too short. My carts looked just like yours. Don't believe, the reload myth, as I have already hear and seen manufactured rounds cause the same problem.

BTW, check you gun out carefully, this KB, may have popped or cracked your polymer case. You can check by removing the slide and check the sides. You may see a small crack. My first KB was a repair job.

Tom

[iCreek]

Yup, 40 S&W is a tricky round to reload due to the high pressure. What was your reloaded ammo combo, bullet, powder, primer, & OAL?

[DCART]

Tom,

It took convincing to get the slide off at the range. At home, it took anudge with an open palm to get the slide to go on. It would cycle snap caps afterthis with no problem. Its back at SA to have them look it over. I'm schedule totake a class with it in March so I need to have a pistol that’s good to go.

Art

[DCART]

Originally Posted by iCreek

Yup, 40 S&W is a tricky round to reload due to the high pressure. What was your reloaded ammo combo, bullet, powder, primer, & OAL?

It was7.2 grains of Unique pushing a 155 Ranier FMJ FP. The primers were CCI 500s. Case over length was 1.12 I’ve loaded over athousand of these and this was the first problem.

[GT Jon]

Originally Posted by DCART

It was7.2 grains of Unique pushing a 155 Ranier FMJ FP. The primers were CCI 500s. Case over length was 1.12 I’ve loaded over athousand of these and this was the first problem.

I dunno man, everything I've got shows that the max charge for a powder as fast as unique would be about 6.5gr. You're pushing that by .7 grains. Where did you find this load? Do you have some pics of the case head of non-KB'd brass? I'm willing to bet we will find signs of overpressure on them.

As for making over 1k rds of this load, perhaps you crimped just a bit tighter, or seated the round just a smidge deeper, or flowed a bit more of a charge than you have before? Tolerance stacking could have led a borderline unsafe load to become a KB. Regardless, I don't think it's the pistol's fault. I think your bad day at the range started with a bad day at the reloading bench.

The Mrs reminded me to ask about how many times you've reloaded this brass? She has a point: at that pressure level the brass would be significantly weakened and a case head separation would be the inevitable result.

[DCART]

Originally Posted by GT Jon

I dunno man, everything I've got shows that the max charge for a powder as fast as unique would be about 6.5gr. You're pushing that by .7 grains. Where did you find this load? Do you have some pics of the case head of non-KB'd brass? I'm willing to bet we will find signs of overpressure on them.

As for making over 1k rds of this load, perhaps you crimped just a bit tighter, or seated the round just a smidge deeper, or flowed a bit more of a charge than you have before? Tolerance stacking could have led a borderline unsafe load to become a KB. Regardless, I don't think it's the pistol's fault. I think your bad day at the range started with a bad day at the reloading bench.

The Mrs reminded me to ask about how many times you've reloaded this brass? She has a point: at that pressure level the brass would be significantly weakened and a case head separation would be the inevitable result.

Jon,

Speer Reloading Manual #14page 917. Starting load of Unique is 7.2 grs Max load is 8.0. These loads werefrom a RCBS Loadmaster. On a very bad day, maybe .2 over. I have yet to find away to positively keep track of brass like I did with my .357 Magnum.

Would even a severe overpressure cause the brass to partially eject AND conform to the ramp andbreech?

Art

[GT Jon]

Did you use more than that one source? There's a reason why serious reloaders look at several loading manuals and average their starting load. My Hornady book aside (listing 6.5gr max for a similar powder by burn rate), I've been poking around the web and keep seeing threads like this:
Need load: 40S&W w/ 155gr plated (Unique) - Calguns.net

1.125" min OAL, with no one running anything close to your charge weight. One guy says that 6.5gr is actually a compressed load! Shorter OAL and higher charger = way higher pressures. With enough pressure what you've shown in the picture is completely within the realm of possibility. Hell, with that much pressure I'm not surprised the pistol may have unlocked EARLY, making it look like it fired from out ot battery when it was the pressures that caused it to do so. Just wild speculation on my part, though.

I think this thread is an almost identical sister-story to your own, but with a Glock and 180gr bullets:
I finally had the .40 KABOOM! (case head separation) - GlockPost

Anyway, end of the story is I'm glad you're OK. A KB is nothing to laugh at, and you're lucky that you came away from it with all digits intact.

[XDMreg]

Was the brass once fired? It looks like from the picture that it blew at the typical Glock Bulge. I wonder if the case experienced high pressures and the case was already split.

[XDMreg]

Originally Posted by tpetaja

I have had this happen twice and the out of battery part, I can believe. I did a check on mind, and I could not get it to fire, out of battery.
Anyway, here is what I believe happen to me. My type of powder I was using, was fast burning and hard to meter. I must likely had overcharged round and also, I was setting my OAL too short. My carts looked just like yours. Don't believe, the reload myth, as I have already hear and seen manufactured rounds cause the same problem.

BTW, check you gun out carefully, this KB, may have popped or cracked your polymer case. You can check by removing the slide and check the sides. You may see a small crack. My first KB was a repair job.

Tom

if the cartridge won't go into battery that leads me to believe the cartridge was bulged at the base aka Glock bulge. Did you gage the cartridge?