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Posted: 8/31/2008 9:52:32 AM EDT
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I did my usual function check after cleaning my weapon but this time it failed. It passed on safe and semi auto. I charged it, put it on auto and pulled the trigger and it fired like it's supposed to but when I held the trigger to the rear and charged it again, the hammer followed the bolt forward. What does that sound like to you? I have a new M16 hammer that I stuck in there but it didn't help. Next I put in a new auto sear just for the hell of it but that didn't help either. I don't have a spare trigger or dissconector at the moment but the dissconector thats in there now is only about 600 rounds old, give or take. I'll order all new parts for the lower but it would be nice to know which part failed on me. None of my guns ever failed a function check before. |
, It's all good. From what I'm reading that isn't a fail but a pass!
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Hmmm, maybe I didn't explain it well enough. This is from the functional check page of TM 9-1005-249-10. Auto- Place selector in auto. Pull charging handle to rear and release. Pull trigger and hold to rear, hammer should fall. (It did) Pull charging handle to rear and release. Release trigger and pull again. Hammer should not fall. My problem is that I didn't have to release trigger an pull again because the hammer already followed the bolt forward while I was holding the trigger to the rear, after the second charge. During a function check the auto sear should catch the hammer. |
During the second part of the function test, you're saying that when the trigger is not being pulled, the hammer is still following the carrier. Correct? Then, when you're performing the first part of your function check, at what point is the hammer being released by the auto-sear? If it is being properly released when the bolt goes into battery, your problem would be your disconnector. But if that's happening, the function check should fail during the semi-auto portion. If the hammer is not being released but is following the carrier, the problem would be with your auto-sear or the hammer, or a combination of both. |
You didn't include all of the text from the TM for the function check. See below. The bold text is part of the TM you didn't include, and it explains why the hammer won't fall after cycling the charging handle when Auto is selected and the trigger held back - - the hammer already fell automatically on its own. From TM 9-1005-249-10; page 3-50: "3. Place selector lever (2) on AUTO. Pull charging handle assembly (1) to rear and release, Squeeze the trigger; hammer should fall. Hold trigger to the rear and cock the rifle. Release the pressure on the trigger and squeeze it to the rear again. The hammer should not fall because it should have fallen when the bolt was allowed to move forward during the cocking sequence." |
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Well okay, Thats not the way I remember things working before. I'll take you fellas word for it. It wouldn't be the first time I was wrong about something. Edit- Gary123, I'm not trying to pick a fight but I didn't leave anything out. My TM reads just as my post does. If it read like your post, I would have realized every thing was alright.  The pic is just so you don't think I've totally lost my mind. |
It will not fall again when in auto and you do not allow the trigger to reset. |
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it should not fall becouse the carrier would have tripped the auto sear releasing the hammer. This would have let the hammer follow the carrier home. Firing the next round if loaded. Working as it should If you would have pulled the trigger and the hammer would have tripped then the M16 would have failed. IE: the carrier would have failed tripping the auto sear ect. |
| If the hammer is riding the carriers arse into battery it is not being held by the auto sear. The auto sear is either moving out of spec on its pivot axis, its worn where it meets the selector, the selector is worn, or the hammer is worn. Also check for play in the hammer on its pivot pin. I'm thinking the suspect parts are either the hammer, the sear, the selector (really doubt it), or the pins for the selector, and hammer. |
Ok so this is how I read it and you can take it for what it's worth... I am wording the entire instructions below from your picture and making comments throughout the process in red bold (parenthesis). Place selector in auto. Pull charging handle to rear and release. (at this point the BCG has pulled the hammer back which was caught by the auto sear and then released by the auto sear when the BCG went forward, which at this point the disconnect got a hold of it, which kept the hammer from falling) Pull trigger and hold to rear. (opening the disconnector and releasing the hammer.) Hammer should fall. (which it sounds like it does, yahoo!) (Now it is important to note that you are still holding the trigger back.) Pull charging handle to rear and release. (at this point the BCG has pulled the hammer back into the auto sear which catches it and then when you release the charging handle the BCG goes forward releasing the auto sear's hold on the hammer, thus causing the hammer to fall because you are holding the trigger back so the disconnector cannot grab the hammer. I think at this point your instructions should say "Hammer should fall.") Release trigger and pull again. (nothing happens because the hammer is not cocked because it was already released by the last step.) Hammer should not fall. (which it shouldn't, again because it fell when we released the charging handle throwing the BCG into the auto sear, which released the hammer, which was not caught by the disconnector because we were pulling the trigger back.) So where you would get into trouble is if you were not holding the trigger back, pull the charging handle and release and the hammer fell. This would mean that the disconnector failed to hold the hammer. Also if this were the case it would fail on semi as someone above already mentioned. I think the problem here is simply how you are reading the instructions. Hope this helps!  |
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With an M-16 style rifle, when the selector is placed on "auto", the selector cams the rear end of the disconnector, blocking its action, while simultaneously allowing the auto sear to rotate forward, allowing it to engage the hammer. The only two devices affecting the fall of the hammer on "auto" are the trigger sear and the auto sear. If you are holding the trigger back, the auto sear will release the hammer to fire the rifle when the bolt carrier closes. If you are off the trigger, the auto sear will release the hammer to fall onto the trigger sear. The disconnector only comes into play when the rifle is set on "semi", whereupon the auto sear is also cammed out of engagement. |
Sorry I meant "trigger sear" then where I put "disconnector". Thanks for the correction!
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function checks are ghey a lot of things could be wrong with it and you wouldent know from the function check. The function check for burst is WRONG because you fire it on SEMI and the burst cam rotates, so when you switch to BURST it would really only fire 1 or 2 rounds on the first burst depending on how you preform your function check. look at it, if its put together correctly its good. I cock the hammer and fire/trip the sear by hand so I can see whats going on. The disconnects should lock the hammer back at the right time. If it works its good. |
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