[Arizona_Mike]

I shot about 20 rounds of 168gr .308 with no issues and when I switched to 145gr I was getting a lot of failures to eject and had to clear several jams. Apparently the jams bent the ears of my ejection chute back to the point they interfered with the recoil springs and the springs were sticking back. The last shot appears to have had no functioning recoil springs (because the slide moved freely) and the back of the top cover was bulged outward. Both ears of the chute were bent past 90 degrees so I suspect that one or more shots besides the last one may have had the benefit of only one spring. The recoil pad was knocked back about 1/4 inch. There is a noticeable bulge in the back of the top cover weldment. My shoulder is grateful that the spot welds held and the assembly bent rather than broke.

Mike

 

[henshao]

I shot about 20 rounds of 168gr .308 with no issues and when I switched to 145gr I was getting a lot of failures to eject and had to clear several jams. Apparently the jams bent the ears of my ejection chute back to the point they interfered with the recoil springs and the springs were sticking back. The last shot appears to have had no functioning recoil springs (because the slide moved freely) and the back of the top cover was bulged outward. Both ears of the chute were bent past 90 degrees so I suspect that one or more shots besides the last one may have had the benefit of only one spring. The recoil pad was knocked back about 1/4 inch. There is a noticeable bulge in the back of the top cover weldment. My shoulder is grateful that the spot welds held and the assembly bent rather than broke.

Mike

Glad you're alright. Glad the RFB is built like a brick ****house so that its riflemen will be alright. Sad that the gas system of the RFB is so quixotic.

Because I didn't hear anything about any clicks or gas settings getting changed I'm assuming they didn't and you continued at the previous gas setting for the new ammo in spite of the rifle's feedback.

 

[Arizona_Mike]

Glad you're alright. Glad the RFB is built like a brick ****house so that its riflemen will be alright. Sad that the gas system of the RFB is so quixotic.

Because I didn't hear anything about any clicks or gas settings getting changed I'm assuming they didn't and you continued at the previous gas setting for the new ammo in spite of the rifle's feedback.

On my last (and only) outing I had the gas system dialed in for the 145 grain. It was a pleasant surprise that the 168s shot so great.

Mike

 

[Arizona_Mike]

Glad you're alright. Glad the RFB is built like a brick ****house so that its riflemen will be alright. Sad that the gas system of the RFB is so quixotic.

Because I didn't hear anything about any clicks or gas settings getting changed I'm assuming they didn't and you continued at the previous gas setting for the new ammo in spite of the rifle's feedback.

On my last (and only) outing I had the gas system dialed in for the 145 grain. It was a pleasant surprise that the 168s shot so great.

Mike

 

[ronmar]

Sounds as if you lost a recoil spring before the main event. Look at the two short tubes welded up inside the carrier. These slide along the spring guide rods and are what compress the springs as the carrier moves to the rear. You may find that one has failed, or one of the springs themselves so you were running on one spring. This probably happened about the time you started having jams. Of course running on one spring causes the top channel rear plate and buffer pad to absorb the remaining energy of the carrier.

 

[Arizona_Mike]

Both springs are intact. I doubt both fingers got bent on the same jam so it is mostly likely I was running on 1 spring for a few rounds before the second spring jammed.

Heard back form Kel Tec. They are sending the chute on the honor system but want the cover plate back before they send a replacement. This is consistent with what others have posted.

Found this picture on line (there is a lot of discussion about this failure mode) that showes exactly half of my problem (I had it on both sides).

Mike

 

[henshao]

What do the extractors look like? Extremely curious how that tab got to that position.

 

[ronmar]

That is kind of weird. That is a good pic. The extractors do not go far enough forward to touch the chute tabs. They actually run in those two notches immediately to the right of the tabs in that pic If the ends of the tabs are bent outward properly, it should not be possible for a case mouth, even one only being held by one extractor to snag on them as the shoulder of the case hits the side of the receiver before the mouth can get far enough out to hit the end of the tab.

One way I could see this happening is if the tabs were spread really really wide. Adjusted normally like the pic below, they are pretty close to the springs. If spread too wide, They could possibly contact the springs and be bent. Or they could be bent during re-assembly by the ends of the guide rods and those two welded tubes, as the carrier is slid onto the receiver. In normal operation, the welded tubes do not come far enough to the rear to catch the tabs.

Here is what the tabs should look like when properly adjusted(click on pic).

 

[Arizona_Mike]

I don't think you are accounting for the next round, esp. what happens to the next round when the previous case is in the way. I had to pull the mag and shake out a live round as well and the unejected case when it was jamming. In two cases I needed to pull them out with my fingers. My recollection was that those live rounds were to the side of the fired and past the chamber mouth to about the shoulder.

Those loaded rounds were so badly mangled (scrapes along the side of the bullet and case neck), I tossed them into the bushes so I wouldn't fire them accidentally.

Mike

 

[Arizona_Mike]

What do the extractors look like? Extremely curious how that tab got to that position.

The extractors look completely normal.

Mike

 

[ronmar]

Yea, but the cases cannot turn sideways in that narrow space, and if the tabs were bent as is shown in my pic, the case simply cannot turn far enough for the mouth to catch the end of that tab. The shoulder and the case rim touch opposite sides of the receiver long before this can happen. I seem to recall a failure where the tabs were not correct from the factory. One of the tabs took a trip down the case mouth, but the resulting jam was plainly obvious as to the cause as the case and chute tried to become one. If you were having an empty interfere with the ejection process, this indicates the tabs were not preventing the empties from sliding back into the action which is their purpose, and were already bent...

 

[Arizona_Mike]

Remember immediately before it started jamming, I fired 20 rounds of another ammo with no issues whatsoever. Since I save brass I was counting and there was the usual "left behind" case (that I wanted to grab because the first 20 rds were match grade cases) . I've also laid eyes on the chute and what it looks like/supposed to look like many times when cleaning or lubing the gun, often plucking that case out when cleaning. When the gun was new, the factory test fire case was lodged there.

Something happened and it happened within 10 rounds of switching ammo.

Mike

 

[BlakeHanson]

Remember immediately before it started jamming, I fired 20 rounds of another ammo with no issues whatsoever. Since I save brass I was counting and there was the usual "left behind" case (that I wanted to grab because the first 20 rds were match grade cases) . I've also laid eyes on the chute and what it looks like/supposed to look like many times when cleaning or lubing the gun, often plucking that case out when cleaning. When the gun was new, the factory test fire case was lodged there.

Something happened and it happened within 10 rounds of switching ammo.

Mike

Check the extractors closely for cracks. They are sometimes only barely visible. If one is broken, the other one will feed the empty case at an angle to the chute wrecking it.
The spring stirrup will hold both parts in place even if they are broken.

. I decided to remove the retainer to see the rest of the extractor, and the assembly fell into pieces.

Another one damaging the chute:

Not that I can tell, the extractors look good. I really do not believe it was over gassing the system...

... He called me back and walked me through taking the bolt apart and come to find out ronmar was correct (sorry about that). One of the extractors was actually broke off entirely! He told me that the as the extractor wore down and fractured, it is what was causeing my random jams and stupid issues. Today I sent my barrel assembly and bolt to KT. Andrew said that this is not a common failure but it is not the first one they have seen. Hes going to replace both extractors and springs in the bolt and fix the ejection ramp and chute. He said it shouldnt take to long at all. KT really does have excellent customer care!

Sometimes to people's surprise, both are broken:

(this one was shooting but jamming and bending case mouths)

And another:

I was just reading some random threads for fun today at work and ran across this one. And a light clicked on... low and behold my extractors are broken too... both sides... snapped clean through just like the OP's pics. Gun still works it just runs a little rough. Will be contacting KT tomorrow.

 

[Arizona_Mike]

Thanks for the detailed and informative reply.

I have quite a few cases that look like that. I removed my extractors, cleaned them, and inspected them under a magnifying lamp. I can't find anything amiss.

Mike