Making the T97 more Reliable (Update #118)

Harbl,
Apply moderate pressure on the forward (away from you) stroke.
No pressure on the return stroke.
The tiny shavings should be collecting on the far side of the filed area.
Use the whole length of the file, not just the middle two inches.
Slow, controlled strokes. You should NOT go at it like a teenager "rubbing one out".
 
tootall said:
Harbl,
Apply moderate pressure on the forward (away from you) stroke.
No pressure on the return stroke.
The tiny shavings should be collecting on the far side of the filed area.
Use the whole length of the file, not just the middle two inches.
Slow, controlled strokes. You should NOT go at it like a teenager "rubbing one out".
Click to expand...

lol - I knew someone would make that analogy.

I'm going in through the bottom of the magwell with a 4" rounded file (trying the 2 feed ramp approach in the OP) - I have about 1" of clearance before I hit the top of the chamber.

I have the rifle resting on a table, perpendicular to me. Basically, the filing action is up and down the feed ramp with contact on the edge where the ramp tapers off and goes vertical with the magwell. If I'm reading your right, are you saying, pressure on the way up, nothing on the way down?
 
tootall said:
Harbl,
Apply moderate pressure on the forward (away from you) stroke.
No pressure on the return stroke.
The tiny shavings should be collecting on the far side of the filed area.
Use the whole length of the file, not just the middle two inches.
Slow, controlled strokes. You should NOT go at it like a teenager "rubbing one out".
Click to expand...

Nice visual on that one tootall.

I am gonna shoot mine first before I do the mod. If it needs it will get filed. Just the like the m305's these might need a little extra love, but unlike the m305's these already look alot better and are shooting better with a minor mod.
 
mspben said:
What mags are you using?

Ben
Click to expand...

Gray metal LAR15 mags from Questar. I have one with a slight back and forth wiggle, so I tried to intentionally cause the jam that everyone is having, and it still didn't happen. Seems to be hit and miss (mostly miss) with these rifles.

Only issue I am having is getting my gas regulator out. Came out no problem for the first cleaning. After 800 rounds, can't get it out. It spins between settings fine. I can get it to go horizontal. Just can't pull it out.
 
Zesty said:
Gray metal LAR15 mags from Questar. I have one with a slight back and forth wiggle, so I tried to intentionally cause the jam that everyone is having, and it still didn't happen. Seems to be hit and miss (mostly miss) with these rifles.

Only issue I am having is getting my gas regulator out. Came out no problem for the first cleaning. After 800 rounds, can't get it out. It spins between settings fine. I can get it to go horizontal. Just can't pull it out.
Click to expand...

It gets quite dirty... mine wouldn't come out after 200 rounds. A light tap on the bottom of the piston will do the trick.
 
I took my t97 out Yesterday for second time and after 5 rounds, it stopped firing. It loads correctly, but when i pull the triger, it doesnt fire. Has anyone else have this problem? I took it apart on the spot and everything seems to be ok, and functioning, but the firing pin does not seem to hit the primer, I looked at the bolt where the striker hits the back if the firing ion and it looks like the firing pin moves too far in the bolt, and does no get struck anymore. It's like if the back of the firing pin flattened out a bit or got shorter. That's my best guess from looking at it, and taking it apart. Everything else seems to be functioning. The firing pin moves freely, and I did not change any setting to the gas system it's set on 2. I shot 250 rounds through it last week, worked well then. Except yesterday, crapped out after 5 rounds
 
G
Cgn99 said:
I took my t97 out Yesterday for second time and after 5 rounds, it stopped firing. It loads correctly, but when i pull the triger, it doesnt fire. Has anyone else have this problem? I took it apart on the spot and everything seems to be ok, and functioning, but the firing pin does not seem to hit the primer, I looked at the bolt where the striker hits the back if the firing ion and it looks like the firing pin moves too far in the bolt, and does no get struck anymore. It's like if the back of the firing pin flattened out a bit or got shorter. That's my best guess from looking at it, and taking it apart. Everything else seems to be functioning. The firing pin moves freely, and I did not change any setting to the gas system it's set on 2. I shot 250 rounds through it last week, worked well then. Except yesterday, crapped out after 5 rounds
Click to expand...

Can you post pictures?

The gas should be set at "1".
 
Cgn99 said:
I took my t97 out Yesterday for second time and after 5 rounds, it stopped firing. It loads correctly, but when i pull the triger, it doesnt fire. Has anyone else have this problem? I took it apart on the spot and everything seems to be ok, and functioning, but the firing pin does not seem to hit the primer, I looked at the bolt where the striker hits the back if the firing ion and it looks like the firing pin moves too far in the bolt, and does no get struck anymore. It's like if the back of the firing pin flattened out a bit or got shorter. That's my best guess from looking at it, and taking it apart. Everything else seems to be functioning. The firing pin moves freely, and I did not change any setting to the gas system it's set on 2. I shot 250 rounds through it last week, worked well then. Except yesterday, crapped out after 5 rounds
Click to expand...

Is the tip of your firing pin broken? Quick check - push the pin all the way forward and check to make sure it comes past the bolt face enough to ignite the primer.

Ben
 
Okay T 97 nuts. I solved the mystery! The reason that our team 97's are having bullet setback issues is that certain magazines are tilting horizontally downwards because the magazines are too slim and the mag well just a hair too wide. What you can do to test this, is load a magazine with two rounds (or snap caps) remove the rear stock, bolt, op rod, etc (keeping the carry handle mounted as it serves just that purpose - holding the rifle while doing this test). Load the mag into the mag well, and with one finger, push the round forward towards the chamber from the base while, with another finger, pushing down gently at the mouth (not depressing the mag spring, just preventing the round from tilting upwards). What you will notice with problem mags is on the right column of the mag, the round will encounter resistance with a problem mag, possibly with the tip of the bullet making contact with the mag well, while the left column will always chamber easily.

On the right column of the mag, the magazine is tilting down slightly, which causes the bullet to be too low to engage the feed ramp when it chambers. The bullet strikes the vertical part of the rifles magazine well just below the existing feed ramp and the gets set back in the case and/or the case neck gets deformed as it violently smashes into the ridge between the two - probably causing the stoppage in the video I posted - where the round becomes seriously jammed in the chamber to the point it can't be cleared through a simple immediate action of racking the charging handle.

Adding a single feed ramp lining up with the right column as per the initial op and a few posts shown here will fix that problem. There probably are other simple solutions to this as well - you could, for example add some sort of spacing media (I was thinking duct tape) on the left side of the magazine, to prevent it from tilting.

I went the route of adding the feed ramps and by trying the two finger round test, ascertained that the ramp was deep enough to prevent the chambering issue. I used a fine, rounded needle file - 6". Initially I tried sung a course, rounded file, and had no luck. Thanks Tootall for the instruction of the correct technique. What I got isn't pretty, bit i think it will work which, to me, is all that matters.
 
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harbl_the_cat said:
I used a fine, rounded needle file - 6". Initially I tried sung a course, rounded file, and had no luck. Thanks Tootall for the instruction of the correct technique. What I got isn't pretty, bit i think it will work which, to me, is all that matters.
Click to expand...

Glad to help.
I should have said something about using a fine pitch, rather than a course one, but it didnt occur to mention at the time. Sounds like you got it sorted out though.
I thought afterwards that my comment of using the full length would likely not be possible in the tight confines of the magwell.
The theory is sound, but it doesnt match the reality!
 
Blarf - let this be a lesson to ya'll... stupid Recruit mistake.

My work bench was a total disaster area when I did a full detail strip, inspection and cleaning. Half a sleep, I realized the trigger group is actually really easy to take a part, so I did that.

Rushing to get to work, I reassembled my rifle and guess what? My bolt grew legs and walked away one me...

I was half an hour late for work because I was cursing and swearing, tearing my shop upside down to try to find the darn thing and I ended up not finding it.

Like I said - stupid recruit mistake. Always lay your parts down, left to right as you disassemble. Always have a tidy workspace...
 
harbl_the_cat said:
Blarf - let this be a lesson to ya'll... stupid Recruit mistake.

My work bench was a total disaster area when I did a full detail strip, inspection and cleaning. Half a sleep, I realized the trigger group is actually really easy to take a part, so I did that.

Rushing to get to work, I reassembled my rifle and guess what? My bolt grew legs and walked away one me...

I was half an hour late for work because I was cursing and swearing, tearing my shop upside down to try to find the darn thing and I ended up not finding it.

Like I said - stupid recruit mistake. Always lay your parts down, left to right as you disassemble. Always have a tidy workspace...
Click to expand...

You'll find it when you get home. It'll probably be under something right in front of you. As males, we tend to be unable to see anything that isn't at eye level in plain sight. Or boobs.
 
Zesty said:
You'll find it when you get home. It'll probably be under something right in front of you. As males, we tend to be unable to see anything that isn't at eye level in plain sight. Or boobs.
Click to expand...

Well, my cleaning/working desk is really tiny and there was all kinds of crap on it when I started. I should have tidied it up in the first place.
 
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