FTEject with suppressor

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  • mammynun

    Master
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    10   0   0
    Oct 30, 2009
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    New Albany
    Situation: My stamp for the Thompson Machine (TM) Isis-2 in 45acp that my wife won from TM at the 2016 NRA convention just came back. This is my first pistol suppressor. While waiting for the stamp, I purchased a CZ P-07 "suppressor ready" and loaded it up with Cajun Gunworks parts. The P-07 is the only pistol I own with a threaded barrel. I also bought a TM 1/2x28 recoil booster/Neilson Device. I had shot ~300 rounds w/o the suppressor, mostly 124gr PPU with some 115 Magtech and Federal 124gr subsonic "Suppressor" as well. All performed as expected out of the P-07 and a M&P 9 FS.

    Problem: The Federal subsonic 124gr Fails To Eject 100% of the time; it extracts from the chamber but the slide doesn't go back far enough for the spent case to even hit the ejector. The spent case is still held by the extractor with the front of the case pressed against the barrel hood... if it went back a little farther I'd probably have a stovepipe. When trying the 124gr PPU I get a stovepipe about 60% of the time. The 115gr Magtech has been 100% so far (50-ish rounds), but it's supersonic and the ejection is so weak that I'm sure I'll eventually get a stovepipe with it as well.

    Since this is my first pistol suppressor with a neilson device, I could use some input before I do anything. My first "anything" will be to try some 147gr ammo. My second "anything" will be to fire the gun more as my thought process is that the extra(?) weight of the 45acp can and it's larger diameter bore aren't playing nice with the relatively new/stiff recoil spring in the P-07... but this is a semi-uneducated guess. I'm guessing backpressure plays less (almost zero?) part in a pistol with a tilting barrel/Browning action? My 3rd course of action would be to find a lighter recoil spring if the collective INGO wisdom is that the OEM is too much for this configuration. Maybe a lighter spring in the booster/LID/Neilson? 4th would be to get a threaded barrel for a 1911 if the P-07/Isis-2 in 45 proves to be an unworkable combination...

    I reached out to TM with a less detailed description of my issue via a Facebook PM, but I suspect the hurricane may be delaying a response.

     

    hemicharger

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    Mar 14, 2008
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    I'm guessing for a 124gr bullet to be subsonic like Federal says, it must have a really light powder charge. I'd just try out some standard 147gr ammo. If that works, just stay away from the 124gr subsonic stuff. I doubt there is anything wrong with your gun. It probably doesn't like weak ammo.
     

    mammynun

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    Oct 30, 2009
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    New Albany
    I'd try the 147gr before changing springs

    I just fired 50 flawless 147gr Federal HST's (my preferred SD 9mm ammo) with the suppressor attached, but I don't want to fire another 450 HST's to be satisfied with the reliability. I will order some 147gr FMJ but I really would like the the pistol/suppressor to reliably shoot whatever I feed it, so we'll see if a lighter recoil spring makes that possible without beating up the gun.

    Here's what the 124gr Federal subsonics do... Every. Time.

     

    NyleRN

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    Dec 14, 2013
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    Scottsburg
    I bet 147gr factory FMJ loads will run just fine without messing with the springs. I know those 124s you have are subs but I'd think you could find the 147s easier.
     

    Bfish

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    Feb 24, 2013
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    I didn't see this thread until just now and it seems like you are on the right track. I am not surprised to hear there were issues with 124 subs and you are shooting 147's fine. As stated up thread it's a safe bet the powder load is too light to keep them subsonic. I'm in for updates and to follow your experience but I'm getting your 147grain FMJs will work just like your HST's
     

    hemicharger

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    Just quit shooting subsonic 124gr Bullets. The charge is too light to cycle your gun. Just use any off the shelf 147gr ammo of your choosing and be done with it. I wouldn't play around springs just to get your gun to cycle some underpowered ammo when switching to 147gr will accomplish the same thing
     

    ikendrick15

    Plinker
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    0   0   0
    Feb 3, 2016
    51
    8
    Evansville
    I have that exact gun and am running a silencerco hybrid and I agree with many others in that I would stick with 147gn because for federal to make 124 gn subsonic it's a light powder charge. I wouldn't personally change springs just to accommodate a specific light load.
     

    mammynun

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    Oct 30, 2009
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    New Albany
    If it was just the Federal 124gr subsonic that had issues I wouldn't experiment with spring rates. But it won't reliably fire standard 124gr PPU, and 115gr Magtech barely dribbles out of the ejection port. I think the additional mass of the can is causing it to be oversprung, or to exhibit those symptoms.
    Since its my only host, it will have the can on it 99% of the time... I'd like to be able to run any ammo through it and I think a lighter spring will get me there. It's an inexpensive and easily reversible change...
     
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