Please help me troubleshoot my ARs FTF issue!

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  • clandestine

    AR-15 Savant
    Oct 13, 2008
    37,031
    Elkton, MD
    I've tried proper lubrication and new mags. Trying to tackle the small things first.. I'll check if the bolt falls into the gas tube without hitch...

    What's next , polish the ramps?

    The ramps need to be recut on the right side, then deburred. Barrel has to be removed for that.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,815
    BradMacc is right but, do the BCG drop first. See what the deal is. Reworking feed ramps involves dismounting the bbl.. Looking at the scratches on the cases shows there is a problem there but, maybe not the ftf problem. Fix the small problems before addressing the big ones.
     

    BigMBobbyOP

    Ultimate Member
    Sep 30, 2011
    1,021
    PA
    It's not hard if you have the proper tools and a steady hand when grinding/polishing.

    Well at least I know what was causing the FTFs now :)

    Guess I have nothing to lose by trying.

    I would appreciate if you are able to share what tools are needed or instructions on the process. I really don't know where to begin.
     

    BigMBobbyOP

    Ultimate Member
    Sep 30, 2011
    1,021
    PA
    BradMacc is right but, do the BCG drop first. See what the deal is. Reworking feed ramps involves dismounting the bbl.. Looking at the scratches on the cases shows there is a problem there but, maybe not the ftf problem. Fix the small problems before addressing the big ones.

    Thanks, will do
     

    clandestine

    AR-15 Savant
    Oct 13, 2008
    37,031
    Elkton, MD
    Well at least I know what was causing the FTFs now :)

    Guess I have nothing to lose by trying.

    I would appreciate if you are able to share what tools are needed or instructions on the process. I really don't know where to begin.

    It's not easy for me to write out, a demonstration is better. If you let me have the upper I'll fix it and video for my youtube channel for all to see.
     

    drkeg

    Member
    Jan 14, 2011
    77
    Catonsville
    "The Barrel extension can cause ammo to not feed. A cratex bit on a dremel works great to fix that."

    Exactly this. If the points and edges on the back side (the side facing you) of the locking lugs at the top of the feed ramps are very sharp, they can gouge and snag the round on the way into the chamber. A bullet shaped cratex bit works very well to smooth them a little. Clean it out afterwards very thoroughly.
     

    BigMBobbyOP

    Ultimate Member
    Sep 30, 2011
    1,021
    PA
    "The Barrel extension can cause ammo to not feed. A cratex bit on a dremel works great to fix that."

    Exactly this. If the points and edges on the back side (the side facing you) of the locking lugs at the top of the feed ramps are very sharp, they can gouge and snag the round on the way into the chamber. A bullet shaped cratex bit works very well to smooth them a little. Clean it out afterwards very thoroughly.


    Thanks I'm thinking about trying this...
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,815
    Honestly I'm thinking about the buffer as well

    Just a thought: Do your changes incrementally, one at a time. That way you'll have a better grasp of what's going on with your rifle. Change-test, change-test, etc.

    It may have been said here before but, it would be nice to see a fired case. We're looking for two parallel scratches on the case, just below the case shoulder. Those scratches are indicative of (repairable) feed ramp problems that clandestine and others here have mentioned.
     

    BigMBobbyOP

    Ultimate Member
    Sep 30, 2011
    1,021
    PA
    Just a thought: Do your changes incrementally, one at a time. That way you'll have a better grasp of what's going on with your rifle. Change-test, change-test, etc.

    It may have been said here before but, it would be nice to see a fired case. We're looking for two parallel scratches on the case, just below the case shoulder. Those scratches are indicative of (repairable) feed ramp problems that clandestine and others here have mentioned.

    Post 44 i think shows a round that got stuck. I'll grab a fired case next time. The stuck one appears to show what you are mentioning if Im reading you right.

    I'm on board with incremental changes. Tried the bolt drop test and everything was ok. I picked up some new ammo and will try that (its Federal 223 Rem 55gr Full Metal Jacket)

    I did see some nicks on the barrell extension where the rounds enter the chamber. You can see it in the pic in post 54.
     

    Erno86

    Banned
    BANNED!!!
    Aug 27, 2012
    1,814
    Marriottsville, Maryland
    Could be a stuck blown primer or primer anvil stuck way back in the gas key. Make sure you have the proper buffer spring and buffer. It might be the gas tube is misaligned, or the gas tube might have an obstruction; and the gas tube vent in the barrel might have to be re-drilled so as to make a cleaner opening.

    The gunsmiths at Duffy's Gunroom can help you out.

    It looks like it is under gassed.

    I'm no expert...but it looks like the bolt carrier has way to much grease. Degrease the bolt and bolt carrier including the gas escape holes on the right side of the carrier, and coat them with a fine oil {I use semi-synthetic motor oil;} leaving the last rear half of the bolt carrier free of oil.

    The buffer tube might also need degreasing. You want to make sure that no excess amounts of grease or oil gets in the buffer tube.

    You'll will also have to degrease the whole inside of the receiver. I use non- chlorinated brake degreaser. Make sure you wear eye protection when you do this.

    I believe I had the same kind of jam...what with the deeply scratched live round shell casings in my AR Smith & Wesson in 5.45x39. I was using corrosive ammo a lot, and I had John at Duffy's replace the gas tube, while he put a new free floated forearm on it; though I believe that he also re-drilled the gas vent tube hole in the barrel. I haven't had a jam since, though I use non-explosive Gunzilla now, by using it with an eyedropper down the gas tube after a blast of degreaser, during my cleanings after using that dirty Russian corrosive ammo.

    If the rifle worked before...and now you're having problems --- it should not be a feed ramp issue ---- IMHO.

    Good luck

    You can order gas tubes from Brownells.
     
    Last edited:

    clandestine

    AR-15 Savant
    Oct 13, 2008
    37,031
    Elkton, MD
    I'm no expert...but it looks like the bolt carrier has way to much grease. Degrease the bolt and bolt carrier including the gas escape holes on the right side of the carrier, and coat them with a fine oil; leaving the last rear half of the bolt carrier free of oil.

    The buffer tube might also need degreasing. You want to make sure that no excess amounts of grease or oil gets in the buffer tube.

    You'll will also have to degrease the whole inside of the receiver. I use non- chlorinated brake degreaser. Make sure you wear eye protection when you do this.

    No
     

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