FS2000 KB- Now with more FN Letter! first post

FS-2000 # 025563 Review

Service invoice # 371191 came into the Arnold Gun Shop for review; the customer claimed it fired out of breech. Portions of the fired case are missing but the evidence that remains indicates the cartridge in question discharged with the action open see photo

After discharging the bolt tried to push the cartridge forward resulting in a bolt imprint on the casing
See
photos.

The ammo sent with the weapon are reloads and it is very possible that they may be the cause of this incident see photo.

In the normal function of the weapon the cycle of operation would position the bolt in the unlocked position to extract and eject the fired round then picking up the cartridge that discharged. The bolt alignment lever would hold the bolt in position during the closing of the action and would not move till lockup which would prevent the firing pin from striking the cartridge in question. Further evidence on the bolt slide indicates that the cam lock struck it with a great amount of energy rolling a burr as it traveled rearward indicating that the position of the parts was correct for the firing cycle.

The amount of energy the bolt struck the bolt slide with and working with the escaping gases resulted in the damage to the stock from the bolt slide attempting to rotate.

One final broken part is the bolt return spring, it is broken and a small portion is collapsed. At this point there is no way to tell if this occurred during the discharge or was damaged before the discharge. Even if it was broken before the discharge, the function of the cam lock and bolt slide position the bolt in the correct alignment when cycling to the unlock position and the bolt alignment lever would then hold it there but here is a photo of the spring.

The evidence that we have points to a cause other than the cycle of operation, the weapon’s parts positions would not allow a firing out of battery. Poorly manufactured ammo could be the cause of the cartridge to discharge out of battery, without the cartridge head to see what struck it; it is impossible to say positively what caused the discharge out of battery. The damage to the parts indicates correct part position at time of discharge.

Best Regards,
Robert Semonis

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Originally Posted By Model_One:
I got a call from my brother Friday afternoon (July 3rd), and he sounded a bit dazed.
No wonder, because his FS2000 had blown up in his face.
The gun was nearly new, and hadn't had more than a few hundred rounds through it.
Luckily, the polymer stock contained and/or redirected the blast away from his face.
He got some light powder burns and some cuts and bruises, but he got off pretty easy, considering. The stock split along the top edge and the top cover blew open, but it appears most of the gas went down through the magwell as we've seen happen with AR-15s. Magazine (Colt 20-round) floorplate blown off, ammo scattered on the ground.
The bolt and carrier was driven back into the stock and is wedged there, and some of the plastic bits were thrown loose, but overall the damage doesn't look as bad as it is - the weapon, or at least the lower half, is a total loss.
He said he'd had some "misfeeds" prior to the incident but upon inspection some of those rounds had very light firing pin strikes.As near as we can determine, there was a fire out of battery, or maybe the bolt closed but wasn't completely locked. I suspect the latter because of some deformation and chipping on the lugs of the bolt and the barrel extension. Or, I suppose it could have been a double or half-charge and it just blew the bolt open. We found the piece of brass you see in the photo below, but we never found the case head - it might be wedged down inside the rifle somewhere, but I'm not taking anything apart at this point, at least until we talk to FN.
He's going to talk to FNUSA tomorrow and see what they say.
Pictures below.
Questions, opinions, guesses?

ETA a couple of things:
1.) I am not blaming the gun, i.e., "the platform."
2.) My brother didn't buy shoddy ammo on purpose to save a few pennies.
He normally uses high-quality ammo, but was shooting with a friend, who provided the ammo. Brother has been counseled on suspecting and inspecting such ammo.

Update: The ammo wasn't reloads but a mixed bag of commercial and mil-surp.
Headstamps are all WCC, F (correction: FC) and LC. I have also learned that there was an issue with early FS2000 carbines that had the military firing pin and spring installed, which caused light strikes and slam fires. This gun came from a dealer who included this gun as part of a transaction for Hummer parts (my bro sells Hummers/Humvees), and he'd had the gun in stock for awhile, so maybe it was subject to the recall. I'll post updates as they come along.

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