re: ***UPDATE NO.3**My new AR is cycling .223 fine but hanging up on 5.56

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And if he is near madisonville/robert I'll take a look at it and we can swap parts from my gun to see what works

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Thanks, I really appreciate that. Im in the Acadiana area so that's a stretch. I will try and post pics tonight when I can and I will follow up with whatever info I gather from PSA this evening. I really appreciate everyones time and responses.

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Drown it in oil and use the forward assist to engage the bolt completely

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I did oil it sufficiently and have used forward assist. It will not lock all the way. The gun has been run wet, for over a 100 rounds. Problem is only getting worse.

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I did oil it sufficiently and have used forward assist. It will not lock all the way.

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Now that you added this, it really changes things. I didn't realize you had tried to use the FA to seat the rounds. LIke I said before, if this was a headspace issue (and you have to be aware that being 0.25" out of spec would be an enormous amount) then it would occur with BOTH the .223 and the 5.56 rounds. Again, they are dimensionally identical. The chambers are different but not the rounds. So either they would chamber or they wouldn't. I am back to wanting to say it's an out of spec lot of ammo but that leads me to ask a few more questions.

1. Are the failures to seat always after you fire a few rounds? Does it occur when you manually chamber?

2. When it fails to seat, are you able to use the Forward Assist to seat and then fire the round? Because when you say you "have used the forward assist" that seems to indicate the round just won't chamber at all.

3. When you "click" on a round, does the ejected live round have a primer strike?

4. You admitted you are a "noob" to AR's so let me ask this. Does it say "5.56" on the receiver or on the barrel? Are you 100% sure that this barrel is chambered 5.56? Have you called PSA to confirm? Because some 5.56 ammunition is loaded to a longer OAL than .223 and WILL cause chambering issues in a .223 chambered barrel. This is the situation I mentioned before that can result in dangerous pressures. Furthermore, I have seen situations where the 5.56 round (in a .223 chamber) will slam into the chamber and fail to seat but then when you whale on it with the FA it will push the bullet back allowing it to seat and fire. Guess what? By pushing the bullet back it is possible to compress the powder and really elevate pressures. Ka-Boom. So maybe put in a call to PSA, I know they are a PITA to get on the phone, and verify your chamber.

Well... They clearly say it's a 5.56 chamber and, fwiw, I hear that PSA gets their barrels from FN. Which is one of the best out there.

So that's a weird one. Back to ammo, set the 5.56 rounds and .223 rounds on a flat surface and compare OAL. Or use calipers if you have them. Because what you are describing, failure to manually seat is completely different than a failure to feed and/or the bolt short-stroking or bolt bounce.

Last question before I punch out. I should have been more descriptive in my prior question.

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quote:When it fails to seat, are you able to use the Forward Assist to seat and then fire the round? No. After using fwd assist, it still will not fire.

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Will the bolt NOT CLOSE or does it close but won't fire? Because, and I keep saying this, they are two different things. If it just flat-out won't close, that is a problem. If it closes but then won't fire, that is normal. That just means you pulled the trigger and dropped the hammer on the unseated round. So when you use the FA to close the bolt, it won't fire not because it isn't seated but because the hammer is down. You have to cycle the bolt to reset the hammer.

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So you are doing what with those rounds that refuse to seat? Throwing them away, putting them back in the box? Because it sounds like bad ammo if some of the rounds won't seat at all and others will

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Picked them up off the ground and put them back in the box. I figured it had nothing to do with the ammo and was the rifle since this was within the first 100 rounds ever being fired through this rifle.

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Because it sounds like bad ammo if some of the rounds won't seat at all and others will.

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It is always the 2nd round out of the mag. That seems to not be coincidental.
-Insert mag
-charge rifle
-1st round fires and ejects
-BCG does not fully lock when chambering 2nd round
-F.A. will no seat round either
-manually pull charging handle back and tilt rifle up and unfired round falls out
-manually release charging handle and it chambers another round fine
-round fires and then next round does not fully seat and BCG is "stuck" approx .25" from being fully locked.

are you certain it is 5.56?
can you see it on the barrel?

should have bought an ak.

I would pick up a different box of ammo just to see if there is any difference... but its unlikely that will fix the issue.

Almost sounds like they put a .223 barrel on there. Id just send it back and get a new one if you just bought this stuff.

Take one more pic of the fire control components in the lower from directly above but with the hammer forward and not cocked like it is in your last pic.

Need pictures of the spent brass cases. Only other thing that might be the issue is a rough chamber or a burr that is taking away from the energy needed to cycle the bolt on the extraction cycle. The hunting ammo you were using might have harder brass or is producing enough energy to overcome a rough chamber. That also means it's putting a lot more pressure on the extractor and bolt which will lead to another kind of failure at some point. When you chamber a round using the bolt release from a fully locked back position does it chamber every time? If you can do it safely on your own property, chamber a round, manually eject and lock the bolt back, then release the bolt and see if it will chamber the second.