XCR-L out of battery discharge

*MALICE* said:
If a 'slam-fire' happens in an AR (lets say due to soft primers and the firing pin hitting it from inertia) the bolt is locked anyway so the bullet goes downrange (cuz that's where you had it pointed...right? ;) )and despite being surprised, all is well. On an AR15 the firing pin can not physically touch the primer until after the bolt is fully rotated/locked.

It seems that in an XCR, since there is nothing mechanically stopping the firing pin from being able to ignite a primer before lockup (aside from a spring), if the firing pin happens to get stuck forward (let's say a build up of carbon?), your gun might explode. I'm not sure if it's possible for the hammer to ride the pin forward and cause the same result in an XCR?

Which isn't to say an AR15 can't blow up. A case head separation can cause that even if the bolt is fully locked.
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Thanks, good explaination, pretty much how I thought it to be.
 
The spring in my XCR is very stiff , it takes a fair amount of force to push it. It would have to take an aweful lot of carbon to build up to keep it stuck open, wouldn't it. And if the pin is always moving back and forth wouldn't this also keep it from being stuck? I have a 1000 or so rnds through mine , and when cleaning , there is very little black carbon on or around the firing pin. I don't have enough experience to fully understand what happened but would like to have some idea , what to be aware of.
 
Brianma65 said:
The spring in my XCR is very stiff , it takes a fair amount of force to push it. It would have to take an aweful lot of carbon to build up to keep it stuck open, wouldn't it. And if the pin is always moving back and forth wouldn't this also keep it from being stuck? I have a 1000 or so rnds through mine , and when cleaning , there is very little black carbon on or around the firing pin. I don't have enough experience to fully understand what happened but would like to have some idea , what to be aware of.
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This is my thinking as well. Im hoping the more educated on the topic can shed some light. The firing pin is held back by a spring. The bolt moving into battery would not, in my amateur estimation, impart enough momentum on the pin to overcome the spring by any meaningful amount. I would assume inly a heavy hammer hit would be able to get a pin to protrude sufficiently to hit a primer.

Also consider how very little the firing pin would ever protrude, I cant imagine how much carbon build up you would need to hold the firing pin in place against the spring.

I would presume only a broken firing pin or spring could cause a slamfire.
 
It wasn't a slam fire, the round never made it into the chamber. This was an OBD.


I doubt the spring was stuck forward either, I'm not sure if the hammer rode up with the bolt carrier or not either. What I can say is the firing pin still moves freely in the broken bolt. Inertia possibly, hammer ridding the bolt maybe, hard to say for sure. The primer has a firing pin hit in it for sure, it is obvious it wasn't from contact with a bolt lug (it's nice and round).

I'm still waiting on someone from Wolverine to call me back, Brent was away when I called and whoever I spoke with was going to look into the parts I need to get this thing back up and running again. I'll try calling back on Monday, hopefully Brent's back by then.
 
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Canadian_Zuk said:
It wasn't a slam fire, the round never made it into the chamber. This was an OBD.


I doubt the spring was stuck forward either, I'm not sure if the hammer rode up with the bolt carrier or not either. What I can say is the firing pin still moves freely in the broken bolt. Inertia possibly, hammer ridding the bolt maybe, hard to say for sure. The primer has a firing pin hit in it for sure, it is obvious it wasn't from contact with a bolt lug (it's nice and round).

I'm still patiently waiting on someone from Wolverine to call me back, Brent was away when I called and whoever I spoke with was going to "look into" the parts I need to get this thing back up and running again. I'll try calling back on Monday, hopefully Brent's back by then.
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Hey Zuk, if the spring was weak or broken , you would think it would just push back in .? The only way I can get my firing pin to move out of battery is if I pull the trigger , while the bolt is closing. Code the bolt and pull the trigger and it fires just before the bolt closes. I'm not , in no way ,saying that's what happened , but you should also look at your trigger group to , to see if there may be a malfunction there.
 
^ I haven't really looked at anything to closely yet, anything is possible. I'm left handed, I was holding the mag well with my right hand, the stock was against my left shoulder and I racked the charging handle with ,my left hand. When the bolt dropped all hell came out of the ejection port, trigger guard and the gap between the magwell and the mag body. It's billowed smoke from every crevice for a few seconds later. 100% certain it detonated inside the receiver, lots of little flakes of brass everywhere.
 
Canadian_Zuk said:
I'm still waiting on someone from Wolverine to call me back, Brent was away when I called and whoever I spoke with was going to look into the parts I need to get this thing back up and running again. I'll try calling back on Monday, hopefully Brent's back by then.
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Wolverine has all the parts I need in stock and ready to ship, I just sent off my CC info. My pocket sure isn't happy about this, but I'll be glad to have my XCR back up and running.
 
I find it quite funny (in a sad and odd way) that people are blaming Winchester ammo (which in this case were handloads- so not even factory ammo) and (soft? - never heard that before) winchester primers, and defending the poor design of the Robarms failure.

I'd bet money the firing pin protrusion ignited the primer prior to or close to, but not quite fully chambering.

Robarms should be footing the bill with a new (and hopefully updated) rifle!
 
beltfed said:
I find it quite funny (in a sad and odd way) that people are blaming Winchester ammo (which in this case were handloads- so not even factory ammo) and (soft? - never heard that before) winchester primers, and defending the poor design of the Robarms failure.

I'd bet money the firing pin protrusion ignited the primer prior to or close to, but not quite fully chambering.

Robarms should be footing the bill with a new (and hopefully updated) rifle!
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I find it funny that your blaming Robinson Arms design while the OP clearly said he used reloads.
Some manufactures will not cover you if you shoot reloads.
 
andrew3081 said:
I find it funny that your blaming Robinson Arms design while the OP clearly said he used reloads.
Some manufactures will not cover you if you shoot reloads.
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Just because reloads were being used doesn't mean they are at fault. The firing pin struck the primer before the round was all the way in the chamber, that tells me it's a rifle problem not an ammo problem. This was an OOB, not a slam fire, squib or case head failure.
 
09outlander said:
Just because reloads were being used doesn't mean they are at fault. The firing pin struck the primer before the round was all the way in the chamber, that tells me it's a rifle problem not an ammo problem. This was an OOB, not a slam fire, squib or case head failure.
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The part where the firing pin struck the primer before the round was in the chamber and this is because it is the gun's fault; this is all based on assumptions, correct?
There are many ways that can cause OOB.
 
beltfed said:
I find it quite funny (in a sad and odd way) that people are blaming Winchester ammo (which in this case were handloads- so not even factory ammo) and (soft? - never heard that before) winchester primers, and defending the poor design of the Robarms failure.

I'd bet money the firing pin protrusion ignited the primer prior to or close to, but not quite fully chambering.

Robarms should be footing the bill with a new (and hopefully updated) rifle!
Click to expand...

andrew3081 said:
I find it funny that your blaming Robinson Arms design while the OP clearly said he used reloads.
Some manufactures will not cover you if you shoot reloads.
Click to expand...

andrew3081 said:
The part where the firing pin struck the primer before the round was in the chamber and this is because it is the gun's fault; this is all based on assumptions, correct?
There are many ways that can cause OOB.
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I finally spoke with Allen at Rob Arms today. He confirmed it is most likely and OBD caused by firing pin inertia and the use of soft primers. Not at all uncommon unfortunately. He is so confident in fact, that RobArms is making a revision to the owners manual to say that ONLY mil spec ammo (hard primer cup) be used in the XCR platform, no commercial ammo should be used. He didn't elaborate if this applied to all calibers or just the 5.56 chambering.
 
So he says that , there was enough force , from the bolt moving forward , to detonate a round? That only seems possible if the bolt , bought up solid. If the bolt is moving forward and hasn't stopped its movement , you think it's possible for the firing pin to slam forward and ignite in mid motion ? It takes a lot of force , just to push mine forward. So are they saying no more hunting rnds to be used? Can you get a mil spec hunting rnd? Does that mean my 1000 rnds of Hornady vmax , are no more good? If it's so common ,what the fack are they waiting for,they just released the new keymod,before that would have been good a time as any.
 
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Brianma65 said:
So he says that , there was enough force , from the bolt moving forward , to detonate a round? That only seems possible if the bolt , bought up solid. If the bolt is moving forward and hasn't stopped its movement , you think it's possible for the firing pin to slam forward and ignite in mid motion ? It takes a lot of force , just to push mine forward.
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Yes, the firing pin has sufficient mass to overcome the resistance of the firing pin spring to allow the pin to protrude from the bolt face as the bolt slams home. If there was a delay in lockup due to dirt, lack of lube, etc.., this can cause the round to ignite before the lugs rotate in the barrel extension (my story). He told me to take a close look at even mil spec ammo that has been chambered automatically (ie, second round from a mag) then ejected without being fired, you should be able to see a slight mark were the pin made contact through inertia.



Brianma65 said:
So are they saying no more hunting rnds to be used? Can you get a mil spec hunting rnd? Does that mean my 1000 rnds of Hornady vmax , are no more good? If it's so common ,what the fack are they waiting for,they just released the new keymod,before that would have been good a time as any.
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I'm not sure exactly what they are saying. All I know is I was just told today over the phone that they would be amending the owners manual to indicate that only milspec ammo be used.

Also, my XCR is a quadrail version with the original style bolt. I have no idea how the new keymod plays into this or if this issue was addressed through the new bolt design.
 
Ok ,that makes sense that the bolt would have to be done it's travel. So, is mil spec ammo only available in FMJ? And what are mil spec primers? Sorry ,I have to ask. I'm gonna be pissed if I just spent $2800 on a rifle that I can't take in the bush, I purchased a rifle that's being promoted as .223 capable and is also capable as a coyote rifle.This is the first I've heard of this issue,and I've been on the XCR forum ,for a while now.
 
Just because everyone likes pics, even if they are of carnage...here is the damage.

BOLT








Bolt Carrier










The offending cartridge remains





My poor receiver, this hurt my pocket the most.





Barrel looks fine, just some powder granules in the chamber, extension and bore. I still need to examine the extension for damaged lug faces.




 
Primer hardness

Canadian_Zuk said:
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I very much doubt this has anything to do with primer hardness, and quite frankly I use Winchester primers a lot and this is the first I've heard them described as such.
This primer indentation appears to be a full on primer strike - doesn't look indicitive of anything less than full primer pin protrusion.

I would imagine Robarms would do nothing less than circle the wagons and blame everything and anyone but their design - par for the course.
 
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