T97 slam fires

[DVX]

So a few weeks ago, I experienced a slam fire with my T97. First time it happened in about 10k rounds through it. That night, I did a complete disassembly, did a full clean, including using Remington Action Cleaner on the bolt. The firing pin was nice and loose. Not mucked up with carbon or oil.

Took it to the range again last week, and it slam fired again. Took it home and did another full clean. Took it to the range last night, and again, multiple slamfires. I confirmed the bolt and firing pin were squeaky clean. It's really wracking my brain to the point where I want to buy a Gen 2 (I have a Gen 1 with the FTU) just for the bolt and firing pin.

Anyone have any ideas on how to fix this? I'm at a loss.

I usually run it on the max gas setting to ensure it cycles. Wondering if that could be a factor, but like I said, the firing pin in the bolt is nice and clean, and moves very freely and easily. It's not full of gunk or anything, keeping the firing pin in the forward position.

 

[tiriaq]

Is the trigger mechanism slipping as the bolt slams shut? Might have nothing to do with the bolt & firing pin.

 

[DVX]

Not sure, but it basically goes like this. I load the mag, rack it, fire a round (1st trigger pull), fire another round, but it fires twice (second trigger pull), then I fire another round (3rd trigger pull) then fire the last round (4th trigger pull). So 4 trigger pulls for 5 rounds fired.

 

[Juster]

With a magazine of 2 rounds, load. Dump the mag. Is it still cocked?

 

[Winz]

Not sure, but it basically goes like this. I load the mag, rack it, fire a round (1st trigger pull), fire another round, but it fires twice (second trigger pull), then I fire another round (3rd trigger pull) then fire the last round (4th trigger pull). So 4 trigger pulls for 5 rounds fired.

Sounds like a trigger mech (sear engagement) issue and/or gunk that is preventing consistent sear engagement between trigger squeezes. It is also possible (on some firearms) that it may be a "bump trigger" issue.

Caveat: I'm not familiar with the T97 specifically but these types occurrences can be observed in various platforms at times.

 

[DVX]

I'll re-check the trigger mechanism tonight, but it was cleaned multiple times. Could be a broken part. I'll check more in depth.

 

[Jarvy]

The T97 has a lot of "bounce" in it's recoil and the trigger has no tactile feedback. You may be "bump firing" (releasing the trigger and pulling again) under recoil without you noticing.

The T97 is particularly susceptible to this because the rocking buffer in the stock delays the recoil impulse slightly, and you can actually pull the trigger and release the hammer at any point during the bolt's forward travel before it returns to battery. The linear hammer will follow the bolt all the way home and act like an open bolt gun, firing immediately when the bolt locks into battery.

I usually run it on the max gas setting to ensure it cycles.

Aside from an initial break-in period if the rifle is giving you problems, this is really unnecessary and after 10k rounds, it is conceivable that the rifle is damaged. Those rails the bolt and hammer ride on are just aluminum after all! As most AK-ish rifles, the system is already overgassed a bit on the normal setting. I've actually done the opposite and put a heavier recoil spring in mine, and noticed the spring inmy friend's Gen 2 is also much stronger than the factory spring in my Gen 1.

 

[easy]

I’m thinking that your disconnector is slipping/moving and not holding the striker consistently.

 

[DVX]

The T97 has a lot of "bounce" in it's recoil and the trigger has no tactile feedback. You may be "bump firing" (releasing the trigger and pulling again) under recoil without you noticing.

The T97 is particularly susceptible to this because the rocking buffer in the stock delays the recoil impulse slightly, and you can actually pull the trigger and release the hammer at any point during the bolt's forward travel before it returns to battery. The linear hammer will follow the bolt all the way home and act like an open bolt gun, firing immediately when the bolt locks into battery.



Aside from an initial break-in period if the rifle is giving you problems, this is really unnecessary and after 10k rounds, it is conceivable that the rifle is damaged. Those rails the bolt and hammer ride on are just aluminum after all! As most AK-ish rifles, the system is already overgassed a bit on the normal setting. I've actually done the opposite and put a heavier recoil spring in mine, and noticed the spring inmy friend's Gen 2 is also much stronger than the factory spring in my Gen 1.

I don't think that's the case. I always hold my trigger down after every pull when firing a semi auto, until I have my target lined up again in the optic, then release the trigger and fire again. Something I learned in the army, and it's always worked great.

Been looking this up online, and everyone says "get a Tavor". I have one, and it also slam fired awhile ago, under less usage than my T97 (about 8k rounds). The firing pin spring had broken into 3 pieces in the bolt, and was jamming the firing pin forward at times. Replacing the spring fixed it. The T97 doesn't have a firing pin spring though.

Where did you get a heavier recoil spring? Finding parts for this thing usually means buying a new rifle and swapping parts.

 

[easy]

If someone tried to do a trigger job and messed with the sear too much, the disconnector will start to move slightly before the sear does.
You’ll likely need a new sear, or build up the lower arm of the disconnector to be able to raise the lifter arm so the disconnector and sear move at the same time, catches and holds the striker reliably.

 

[Jarvy]

I don't think that's the case. I always hold my trigger down after every pull when firing a semi auto, until I have my target lined up again in the optic, then release the trigger and fire again. Something I learned in the army, and it's always worked great.

Something I learned in the army as well, but it still happened to me with this rifle. (Before I replaced the spring to soften the recoil, which is why I suspect it was a bump fire and not something else)

Been looking this up online, and everyone says "get a Tavor". I have one, and it also slam fired awhile ago, under less usage than my T97 (about 8k rounds). The firing pin spring had broken into 3 pieces in the bolt

The whole reason why Tavors have firing pin springs is because the ones they sold to us would slamfire with commercial ammunition, which sometimes uses softer primers. The "hammer following the bolt home" in the T97 is something I have actually tested for and I found I could only induce a slamfire with commercial ammunition.

Where did you get a heavier recoil spring? Finding parts for this thing usually means buying a new rifle and swapping parts.

In my case, I got a normal weight Wolf recoil spring for an AK from brownells, and cut coils off the end until it did not take undue effort to cycle by hand, but would also cycle reliably with a variety of ammunition. For me this, was 6 coils. Because one end of the spring needs to "plug" into the linear hammer assembly, make sure you only cut from the other end.

 

[DVX]

With a magazine of 2 rounds, load. Dump the mag. Is it still cocked?

I'll run that the next time I'm at the range, but the slamfires so far only occurred in the middle of a mag (usually after the 1st and second shots). Never at the end. The bolt always held open after the mag was empty.

 

[DVX]

If someone tried to do a trigger job and messed with the sear too much, the disconnector will start to move slightly before the sear does.
You’ll likely need a new sear, or build up the lower arm of the disconnector to be able to raise the lifter arm so the disconnector and sear move at the same time, catches and holds the striker reliably.

Aside from the FTU, everything else is OEM on the rifle. Never modified any other part.

 

[alpining]

If someone tried to do a trigger job and messed with the sear too much, the disconnector will start to move slightly before the sear does.....

From what you've described DVX, it sounds like it's a fire control issue. Like easy says, if someone monkeyed with it, that would be my first guess. If not, it's possible that either grime or worn / slightly out of spec parts could be causing the issue.

For next steps, I'd do a detail clean and inspection of the fire control to look for anything suspicious.

 

[twyeh]

This is a common problem, some say its bolt bounce causing auto bump firing, some say its sear engagement issue.
The only remedy is to increase trigger spring weight, that seemed to lesson this for me.

 

[JohnnyP636]

This is a common problem, some say its bolt bounce causing auto bump firing, some say its sear engagement issue.
The only remedy is to increase trigger spring weight, that seemed to lesson this for me.

The one and only time I shot a T97 it went burst fire/full auto on me and dumped the rest of the magazine with one trigger pull. The owner said he just had that issue fixed and doesn't happen to him anymore, but somehow the way I operated the trigger I was able to bring the issue back.

 

[DVX]

The one and only time I shot a T97 it went burst fire/full auto on me and dumped the rest of the magazine with one trigger pull. The owner said he just had that issue fixed and doesn't happen to him anymore, but somehow the way I operated the trigger I was able to bring the issue back.

Its not a trigger operation issue, but never the less, if it was, it shouldn't be slam firing. The only time it's happened to me (when using my Tavor), it was a malfunction of the action. in my Tavors case, the firing pin spring was completely destroyed in the bolt, and was causing the firing pin to remain in the forward position at times, and was fixed with a spring replacement.

Still trying to narrow down where the failure is on the T97, and get it fixed.

 

[73582]

Floating firing pin, take the bolt apart and look for debris. Any of your primers pierced? Check hole for firing pin in bolt face, any excessive wear, meaning is he hole bigger than it should be, is the firing pin worn where it comes thru the bolt face?

 

[JohnnyP636]

Its not a trigger operation issue, but never the less, if it was, it shouldn't be slam firing. The only time it's happened to me (when using my Tavor), it was a malfunction of the action. in my Tavors case, the firing pin spring was completely destroyed in the bolt, and was causing the firing pin to remain in the forward position at times, and was fixed with a spring replacement.

Still trying to narrow down where the failure is on the T97, and get it fixed.

Only going by what the owner stated to me at the time, I was shooting my X95 at the range in the lane next to him and he offered me to try his T97. I pulled the trigger twice first was a one pull one shot the 2nd dumped the rest of the 5 round mag on me till empty. The owner stated that it does not happen to him anymore since having the gun "fixed", and that it must be the way I manipulated the trigger that made the issue come back. I did not say anywhere that your issue is a trigger operation issue. He shot the gun after me and was able to get it to fire semi auto.

Simply sharing my experience with the T97 and what the owner told me at the time