Out of battery detonation

[bobm]

I have been bench testing this new Ruger GP 100 .22LR this week. So far 525 rds. of assorted brands of ammo have been tested at 25 and 50 yds. Amazing bench rest tested accuracy.

Late today while firing round #4 in the cylinder, #5 next in line detonated also. The report was quite loud and shreds of shaved lead landed on the bench table. I observed a chunk of packed in lead around the barrel tenon and some shreds inside the frame opening.

Overall I did not see any physical damage to the revolver and it dry functions as it should. I have a mess to clean up but seems no harm done to the gun.

What could have been the cause of this round going off?

thanks, bobm

 

[1Merlin]

If you haven't cleaned it yet don't and send it to the factory. Send they pics to the rep you talk to when you get the return info. When the see the photos they WILL ask you to return the gun.

 

[Bill K]

Call Ruger as suggested before you take any further steps.

 

[450BM]

did the rim of the cartridge just fired have a hole in it? Or a weak spot on the case of the one that fired out of battery? Doesn’t seem possible it’s a fault of the gun…

 

[tmwinds]

It would be interesting to see a photo of the cartridge case that fired out of battery, especially the case head and rim.

 

[bobm]

It would be interesting to see a photo of the cartridge case that fired out of battery, especially the case head and rim.

I have a close up photo of all five fired cases involved. I am not ready to post the head stamp brand....yet. None of them show any signs of failure, four having firing pin impressions.

The 50 rd. box was taken out of a 500 ct. brick. I had not yet fired this ammo in the Ruger. It performs very well in my CZ 457. It is a popular domestic brand, 1240 fps. non- plated.

Needless to say it will not be used in the Ruger again.

 

[Barrelhorses]

Sure seems more likely to be an ammo issue than a issue with the GP100. But better to be safe than sorry and let Ruger check it out.

 

[Coyotefurharvester]

If nothing stuck the round in chamber 5, than heat caused the out of battery discharge. How fast were you shooting/loading?

 

[Aero]

Yup, seems like an ammo issue. Doubt it was heat. Probably didn’t get to 50* at the range today

 

[Coyotefurharvester]

Well I have thousands of rds of 22rf sitting/stored as do thousands of other shooters They don't fire on their own.

 

[243winxb]

.278" is maximum rim diameter. By the looks of the cylinder, rims may contact each other?

Brass expands on firing, sets off next round?


Or cylinder timming is off, fired while cylinder was not locked? But 4 have firing pin mark & #5 dont, so not that?

Design of cylinder at fauly?

 

[bobm]

I will have to rule out rim contact as seen in the photos. Also not heat, gun was run slow and steady looking for best accuracy. Ambient temp was 42F in the shade. Prior to the episode I sent 250 rds. of mixed brands down range today.

This leads to me thinking very sensitive priming compound?

The ammo shown is NOT the suspect problem ammo.

I will be contacting Ruger in the morning.

 

[hoz53]

I have been bench testing this new Ruger GP 100 .22LR this week. So far 525 rds. of assorted brands of ammo have been tested at 25 and 50 yds. Amazing bench rest tested accuracy.

Late today while firing round #4 in the cylinder, #5 next in line detonated also. The report was quite loud and shreds of shaved lead landed on the bench table. I observed a chunk of packed in lead around the barrel tenon and some shreds inside the frame opening.

Overall I did not see any physical damage to the revolver and it dry functions as it should. I have a mess to clean up but seems no harm done to the gun.

What could have been the cause of this round going off?

thanks, bobm

good to hear you didnt get hurt

 

[243winxb]

The case head would need to hit the recoil shield, hard.
To fire......
1.Firing pin needs to loose contact with round #4 after firing. This requires hammer bounce or an inertia firing pin.
2. The cylinder endplay will need to be excessive. When 4 fired, cylinder & #5 moved back, striking the recoil shield.
3. Headspace may need to be at minimum or under size.
4. Round 5 needs to not be fully chambered. Sitting above the recessed cylinder.

A lot to take place at 1 time.
Issue with priming compound?
We may never know. Just my guess.

 

[akajun]

I’d be looking for a crack or hole in the detonated case

 

[bobm]

good to hear you didnt get hurt

Thanks, hoz53. You will never catch me not wearing safety glasses while shooting.

As said earlier, no cracks, pin holes, etc. are visible under magnification.

The cylinder end play when closed is very minimal and probably within spec. The next up round case head is about 75% supported by the recoil shield which has a cast in "ramp" to press in a raised head if needed.

I have emails sent in to both Ruger and the ammo manufacturer. I have confirmation of them being received by both.

I will keep you posted.

 

[K22]

Following with great interest.

I have literally shot thousands upon thousands of 22 LR rounds in revolvers albeit, 6 shot cylinders in a variety of brands of ammo and pistols and never had this happen or seen it happen. Very strange.

Keep us posted, very interested.

PS: Would the 10-shot cylinder with rounds in close proximity have any influence? I can't see how it would, yet this seems to be the only distinguishing factor from my 50+ years of shooting revolvers.

 

[bobm]

Like you, I have five plus decades of experience. I have never had anything like this happen with rimfire ammo. What would have happened if it went off in a 10 shot Mark I or 10-22 rotary magazine?

That bad round had four chances to clear the frame, and five chances of striking the frame on that $900. Ruger.....assuming a full cylinder.

I have an early 50's Iver Johnson Model 55 8 shot 6" revolver you can bet won't get fed that ammo.

 

[DGP4]

I’d be looking for a crack or hole in the detonated case

This is the only way this could happen as far as I am concerned. You should preserve and photograph the case to see what went wrong.

 

[hoz53]

Thanks, hoz53. You will never catch me not wearing safety glasses while shooting.

As said earlier, no cracks, pin holes, etc. are visible under magnification.

The cylinder end play when closed is very minimal and probably within spec. The next up round case head is about 75% supported by the recoil shield which has a cast in "ramp" to press in a raised head if needed.

I have emails sent in to both Ruger and the ammo manufacturer. I have confirmation of them being received by both.

I will keep you posted.

ok