This is a discussion on Pistol Malfunction Troubleshoot within the General Firearm Discussion forums, part of the Related Topics category; I was at the range this afternoon with my SW99 .40 cal. I had put about 17 rounds of 165-grain Federal Hydra-Shok JHP through when ...
I was at the range this afternoon with my SW99 .40 cal. I had put about 17 rounds of 165-grain Federal Hydra-Shok JHP through when I got a nasty surprise.
I'll try to describe what I think happened, perhaps people can help figure out possible causes.
The instant I squeezed off the round I thought for sure my barrel blew up. The tip of my trigger-finger back to the start of the webbing between my thumb hurt like hell. It seems as if the blast exited through the space around the trigger, rather than chasing out the muzzle-end.
At this point there was no barrel obstruction. An unfired round jammed/locked the slide (though the slide was much further forward than in a typical jam), and the round below it managed to jam the mag.
I've put a few thousand rounds through it with only one jam (that I know was due to limp-wristing). I don't usually shoot the more expensive carry-ammo at the range, though I work enough in to be comfortable with it.
Any thoughts?
*Previous round didn't clear muzzle, obstructed barrel causing next round to cause "explosion"?
*Issue with grain? Ammo?
*Bad magazine didn't allow round to enter chamber clearly?
After I cleared/inspected, I put another 75 rounds through without a single issue.
Damn good question...I'm starting to wonder if the cartridge case burst...you'd think I would have been smart enough to grab that...I'll have to take a ride back in the morning...
It could have been a high pressure load. Sounds like you almost had an encounter of "Super Face" too. If you had a squib round (a round that fires, but does not have enough energy to push the bullet out of the barrel or cycle the slide) that could cause the obstruction. But then, if it were a squib, your slide wouldn't have cycled a fresh round anyways, unless you were using light springs.
My money is that it was an overpressured round from the factory. Usually one in a million, but it does happen. Being that it's 40 and 165, the average FPS is 950 with 350 lbs of energy. If the round was seated deeper, or was overcharged with powder, it would have bumped up the pressure.
Not sure about the .40 but - looking at my 99 in 9mm - case support is all but total - so unless the .40 chamber is ''Glock-like'' can't see that as being involved.
Does indeed seem like a freak high pressure round - unless somehow too the round could fire before fully into battery. But 75 rounds more with no prob's tends to rule that as unlikely.
unless somehow too the round could fire before fully into battery.
My Steyr M40 can do that. Something that suprised me. Pressed the *unloaded* muzzle against my palm and pulled the trigger. Perhaps dmband41's pistol can fire out of battery, and a ruptured case was the result?
My Steyr M40 can do that. Something that suprised me. Pressed the *unloaded* muzzle against my palm and pulled the trigger. Perhaps dmband41's pistol can fire out of battery, and a ruptured case was the result?
Sounds like a overpressured round. Also might want to check the pistol over carefully , fieldstrip and inspect for any cracks, hairline fractures. Especially in the frame portion.
Personaly I am wondering if somehow a 9mm got mixed in with the ammo and fired , this can be done , and can lead to some blowback that possibly woud exit as described. found a pic online showing cases that this had happened to in a .357 sig.
Make sure you get full value out of today , Do something worthwhile, because what you do today will cost you one day off the rest of your life .
We only begin to understand folks after we stop and think .
Ok, back to the range and recovered all of my rounds.
In addition to the 165-grain, I had also let off a mag full of 135-grain (still Federal Hyda-Shok JHP).
All of the 165 shells show even bulging around the base.
Four of the 135-grains show an uneven bulging that gets progressively worse until the fourth round, which clearly burst.
Additionally, the marking left on the primer by the firing pin is something like a dot w/ a "tooth" on every shell I've ever shot...but the one that blew has the dot with no tooth, leading me to believe that the cartridge wasn't seated in the chamber properly.
Now I'm concerned that the cartridges were not being stripped into the chamber properly. Perhaps it wasn't an overloaded round...it probably should have blown up in my face!?
Any other thoughts would be appreciated.
On a personal note, it's refreshing to have found a board where people are actually helpful rather than rude and obnoxious!
Bill
PS. In the 4th pic below, you can see the light passing through the crack that was blown open at the base.
That bulge in 2nd pic - RH case is pretty severe! It looks worse than what I'd see from a typical unsupported area from a Glock. I am still thinking somehow the round was not in battery but as to why - no idea so far.
Your usual FP marking is very common in several semi's.
You're not going into battery all the way, or unlocking too soon. That would be more likely.
The firing pin mark you mentioned is firing pin "wipe." What causes this is a firing pin that has not fully retracted by the time the case ejects, dragging the firing pin across the primer.
I believe the timing is off and it should definitely be inspected by the factory. Don't shoot it anymore until it's been cleared.
The poster who said that the chamber is fully supporting is correct, unless they have changed it since my friend had one of the originals years back.
Check the lockup. Make sure it's engaging well. IIRC it's just a modified Browning action so it won't be hard to tell. Make sure the barrel and slide travel a ways together. I'm thinking this should be 1/8" on this pistol, but it could be as great as 1/4". I disremember. It's similar to a Glock in travel length.
Josh <><
Last edited by Joshua M. Smith; November 18th, 2006 at 11:59 PM.
From what I see, looking at the 2 cases standing up...............Does anybody else observe the case on the left to be slightly longer? or is it my imagination? might want to check the O/A case length.. It seems to me you might have a case, or number of cases that might be too long...........thus.........an out-of-battery type discharge..
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