OBD - out of battery discharge - BANG!

[Roger Rapid]

I know there have been a few posts on this topic before, but just wanted to share an incident that occurred yesterday at our match. Shooter had a jam in his .38cal '73; the next round would not go into the chamber and got stuck on its way in. Shooter used a long 1/4˝ diameter brass rod and sent it down the bore with a hefty effort to dislodge the round. The round got dislodged but - and this point we're not clear on - on its way back the primer either hit the bolt hard enough to have the firing pin float forward and hit the primer, or the cartridge cocked up at an angle so the primer could hit the extractor (which I think is a bit iffy), or the elevator was low enough for the primer to hit the cartridge alignment tab on the bottom of the bolt. Regardless, BANG, the cartridge exploded, shooting the rod out of the gun and into the berm, pieces of brass were strewn on the table, and the burn marks you see. I was writing down scores on the unloading table right next to the shooter - and the shooter and I both got quite a blast - thank goodness for safety glasses!

 

We never clearly found the cause of the jam. Pretty sure it wasn't a squib - at least spotters and TO didn't think it was. And if there was a squib there, it probably wouldn't have driven both the squib and rod out of the run. Might have been a cracked case where the butt end came off leaving the body of the shell stuck in the chamber (and we don't know if the little piece of the cartridge's rim to the left in the photo was from the cracked case of the OBD round).  Hmmm.

 

Any thoughts on whether it was a extractor, firing pin, or alignment tab that hit the primer?

RR

[Kid Rich]

Have to see what the primer looked like.

kR

[Tex Jones, SASS 2263]

It sure feels like there was a squib, as the round in question would not chamber. But if so, then the round going off expelled the rod, squib and bullet of the detonated round, which seems unlikely given that the case ruptured on the carrier block when the primer detonated the powder.  As Rich said the primer might give an indication of what set it off.  It's possible that the rod pushing against bullet forced it straight back against the firing pin.

[Dusty Devil Dale]

Sounds pretty extreme.

 

I was making my own snap caps for my '73 about a year ago.  I simply loaded a round with  everything except a primer, planning to fill in the primer pocket with silicone.  After loading it, I proceeded to the bench grinder to grind off a section of the case head so the extractor wouldn't catch and remove the round in repetitive firing.  I forgot I had a powder load (3.3 gn of Titegroup) in the case.  During grinding the round heated up and  discharged in my bare hand.  I never found the case or bullet in my messy shop.

I was startled, but I  received no burns and no injuries at all!

Lesson learned!

 

Regarding your description, my bet is the heavy brass rod jammed the case back hard enough against the inertia of the F.P. Extension to depress the firing pin spring and allow the F.P. to protrude and hit the primer.  The primer should reveal clues to what struck it, if it can be found. 

[Abilene, SASS # 27489]

I'm guessing the primer blew out of the case head and won't be found.  I have seen some '73's where the Firing Pin protrudes from the bolt during part of the cycle.  For example, if you dry fire the rifle with no cartridge, the firing pin sticks forward until you start to open the lever.  But I'm thinking you would have already noticed this while investigating.

 

But if the hammer was resting against the FP extension at the time, that would make the FP come out of the bolt face as the bolt was pushed back from the force of the round going backwards (I think).

[Colorado Coffinmaker]

Well, well.  Anybodies WAG is a good as anybody else's WAG (WAG - Military acronym for Wild A$$ Guess).  I personally like Abilene's WAG.  

 

Betting the hammer was against the Firing Pin Extension Rod and the rod down the barrel slammed the stuck cartridge back against the Breach Block (Bolt) face, extending the Firing Pin and firing the cartridge.  Whether or not that is what actually happened??  Anybodies WAG.

 

Without having High Speed Cameras in place to document the event, it's like it never happened.  Even if it did.  Would appear the biggest injury was to a couple pair of shorts.  Sometimes you just get lucky.

[Charlie Harley, #14153]

4 minutes ago, Colorado Coffinmaker said:

Would appear the biggest injury was to a couple pair of shorts.  Sometimes you just get lucky.

Slight disagreement on this point.
 

Luck is what happens when preparation meets a situation, either good or bad. 

 

Safety glasses. Long sleeve shirts. Muzzle pointed down range. 
 

That’s preparation that met a bad situation, so I guess you could say “luck happened” and nobody got hurt. 

 

I got nothing to add regarding what caused the bad situation. Not familiar with a 73’s workings. 

[Tequila Shooter]

From what I know (and as it happened to me) ‘73’s can get a OBD from inertia of the firing pin.  Be thankful no one was hurt make sure nothing got bent and chalk it up.  

[Garrison Joe, SASS #60708]

One more reason never to slam the action lever OR the clearing rod when a live round is still in the rifle.     

 

The easiest part of the action to have impacted the primer was the extractor tip.  The cartridge support tab is a possibility, but it does not have as much projection out from the bolt face. 

 

Putting a rag or a chunk of leather just behind the case head before slamming the clearing rod into the barrel would probably have prevented a dangerous discharge, too. 

 

good luck, GJ

[Roger Rapid]

To some of the earlier comments about the hammer's involvement, the lever was fully open, so the hammer was under the firing pin extension.

 

Would be interesting to inspect the primer, but in the excitement of the moment only the pieces you see there remained.

RR

[El Catorce]

@Hoss sure sounds familiar right?… similar thing happened to me except with an additional magazine detonation while pounding out the stuck round in the chamber… and without the squib rod flying out….

I posted about it here about a year ago…