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Discussion Starter #1
I've had no more FTEs since replacing my PT709 extractor, but then, I haven't fired that many rounds yet.

I have given some thought to the underlying problem. In every case, my gun extracted the empty casing part of the way out of the chamber. This indicates to me that the extractor probably had a grip on the base of the casing but lost it as the slide moved aft and the barrel tipped down (which also moves the base of the shell casing lower). It would be interesting to watch high-speed video of this (where are myth busters when you need them?) but I don't have such a camera and I don't want to "break" my gun again just to test this. So I speculate the underlying problem may be one of the following.

1. The extractor never had a grip on the shell and the partial extraction was done by the loaded chamber indicator (which must release as the shell slides down with barrel tilt).
2. The extractor had a poor grip because the flange at the base of the shell perhaps because the shell flange was thicker than the gap between the bolt face and the extractor claw. Maybe there is another cause for a poor grip, like weak extractor spring, slightly out of battery, or dirty/greasy extractor piston or slot.
3. The detailed geometry of the extractor allows the claw to slip off the shell as the barrel tilts.
4. The partially-extracted shell binds in the chamber as the barrel tilts and this forces it to pull loose from the extractor.

I discount #4 because a new extractor seems to have fixed the problem. I tend to suspect #2 or #3 because these extractors are MIM parts where tolerances are not as precise as machined parts. MIM parts are cast oversize and they shrink when heated to consolidate the metal. It seems to me that this also guarantees variability in precise dimensions, which may explain why some guns are 100% from the start while others have chronic FTE problems.

I'd be interested in the thoughts and experience of other 709 owners. This seems to me a good CCW gun but only if it's reliable. I would be more confident in the gun if I thought I understood the original problem and knew I fixed it.

Scott
 

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You forgot one or two possibilities:

1. A recoil spring too heavy to allow the pistol to cycle properly.

2. Underpowered ammo, which has the same effect as #1.
 

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Scott, Are you having failure to eject or failure to extract? How many rounds have been run through your PT709 with this issue? What type ammo were you using while this happened? By the way, I have a PT709 and it has cycled pretty much flawlessly since I traded for it. My missus has a PT111 and it also has cycled flawlessly. We have run inexpensive range ammo through both pistols, reloads, hollow points of various manufacture, etc. Here is a pretty decent recap of failure to eject and failure to extract causes:

Mr. Completely: Curing Failure to Eject or Extract
 

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Discussion Starter #4
"You forgot one or two possibilities"
I don't think so. In every failure I experienced, the shell casing extracted between 1/4 and 3/4 out of the chamber but stopped there; meanwhile the slide continued all the way back, reversed, and stripped the next round (which subsequently jammed under the partially-extracted shell casing). So it appears the slide makes the full travel but looses the grip on the empty shell before it's completely out of the chamber.

"Are you having failure to eject or failure to extract"
Failure to extract in all cases. Ammo was mostly Federal Champion FMJ (Walmart) plus some others. Never had a problem with self defense rounds but I don't practice with that many of those. The gun has a few hundred rounds through it but I haven't kept records. After the first hundred or so rounds (without FTE problems) the gun went to Miami to get a short front sight; they also replaced the barrel and who knows what else. FTE problems began soon after that. Then I replaced the extractor with one I ordered from Taurus and have had no problems since (maybe another 100 rounds). Just looking, the old and new extractors don't appear different. Thanks for the link but I don't agree that normal extraction is done by residual pressure. By the time the slide has moved aft and the barrel unlocked and tilted down the bullet and the pressure are long gone so extraction is mostly the extractor plus a little inertia (shell moving while barrel stops). What you say is true for blowback operated semi-autos but mot locked-bolt recoil operated guns
 
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