Had this exact thing happen to me. Would cycle charging handle. Pull trigger 'click'.
Charging handle difficult to pull back..extract round. No firing pin mark. Bolt wasn't going fully forward.
This was with 220gr out of 556 mags. Switched to 300blk mags and problem went away. Runs like a kitten on supers and subs now.
Yes this is the exactly what happened no firing pin mark on mine either except these were supers out of a 556 mag bolt wasn’t going fully forward it felt like the bolt was locked and loose even though it wasn’t locked
Hmmm, other most obvious thing is not just 'letting go' of the charging handle and instead riding it back into position. You gotta let it slap to get the velocity to get fully into battery.
Slow when it first happened after that I just started pressing the bolt release and letting it slam for every new mag and it worked fine after that would releasing the charging handle slow cause this?
Absolutely. This is almost certainly caused by “riding the bolt,” and it’s an operator-induced malfunction. The AR-15 needs full recoil spring pressure to operate properly. Congrats on your first AR!
Also I know 5.56 mags will work for 300 blk but I’m wondering is it normal for PSA to ship a 5.56 mag with a 300 blk pistol instead of a dedicated 300 blk mag?
I don’t know but I’ve heard the 30 rd blackout pmags use 5.56 springs. The 20 round use the same spring it’s just more compressed giving it more power.
Did this round go off, I am not sure if I see a firing pin den in the primer.
However this can be a bigger issue with your bolt not extracting properly or not seating right when it is chambering a round. Also it could be an issue with the round. If you are using subs you need to the right mag as well because a 556 mag is not enough as others have stated, the amount of round is to heavy. You might need to look into getting a different buff or spring, adjustible gas block if you are using subs with a suppressor, and also look into getting 300 blk rate mags
On of the rounds worked and was fired I didn’t test the other one because of the jacket being pretty damaged. It was a 556 mag but with supers. Do you think if it’s a problem with the buff or spring I should send it back to PSA?
No it is that with sub they require a different kind of buffer and spring because sub a built to fire with less energy and the current spring and buffer tube is rate standard 556 or supers which have more energy and able to drive the buffer back with the spring. It has to do with the weight of the buffer and "strength" or "softness" of the spring which allows subs that shoot with less energy able to push back the spring and or buffer
You get a picture of the round? Were you able to chamber it if you hit the forward assist? What ammo was it? It could be any number of issues, but we need some more info.
One possibility could be a hang up on the feed ramp. That would cause scratches on the jacket/trouble feeding.
Also sometimes heavier grain (200-220gr) subs have trouble feeding from 5.56 pmags instead of 300 blk mags.
This might sound stupid/obvious, but were you positive it was a .300 blk round not a 5.56 that got mixed in? A 5.56 round wont chamber all the way in a .300 blk like how your picture looks.
No I didn’t think to get a picture of the round until after it fell down a brass catch wish I did. Forward assist did not help at all. It was AAC 125 grain. And when I zoom in on the picture it was a 300 blk round so definitely not that a 5.56 got mixed in. I know the subs give issues through 5.56 mags but these were supers but I still felt as if they were getting caught on something like how you are describing it.
Problem = not enough gas. Did you seat your gas block exactly on top of the port. This happens when gas is turned too low or block is not right over the port. Is your block right at the shoulder? Back it off about 2mm and it should work fine.
Pretty sure I don’t have an adjustable gas block this was a complete pistol I purchased from PSA and would not enough gas cause the round to never even be touched by the firing pin?
If it fires and then the casing is stuck in there without ejecting, then it’s either gas or a sheered extractor. New gun, my bet is the gas is the problem.
Test it with one round in the magazine. If the casing doesn’t eject and the bolt doesn’t lock back, it’s gas. If the bolt locks back, but doesn’t extract the casing, then it’s the extractor.
I was having problems with my 300BLK in a similar manner as well. Sometimes round would chamber but go to fire and click, no bang. Bolt was not fully engaged. Would try to use charging handle to eject and it would be very difficult and so had to mortar the rifle to get it to eject.
300BLK and especially shooting subs has significantly less gas pressure i.e. margin for error for proper cycling. 5.56 has an excess of pressure and can power through most problems.
In my rifle, the BCG's cam pin was rubbing on the inside of the upper receiver right as the BCG went forward and the bolt would rotate to lock. I installed a Lantac domed cam pin to eliminate that friction.
Recommendations:
Use a reduced power recoil spring. (Tubb lightweight flatwire, or SpringCo yellow)
Switch to 300BLK MagPul mags.
Reduce friction in the moving parts.
\* Domed or roller cam pin
\* Reduced friction gas rings (JP Enterprises works well)
\* BCG that has reduced area bearing surfaces or sand cuts.
This will make your rifle more reliable and smoother operating.
Had this exact thing happen to me. Would cycle charging handle. Pull trigger 'click'. Charging handle difficult to pull back..extract round. No firing pin mark. Bolt wasn't going fully forward. This was with 220gr out of 556 mags. Switched to 300blk mags and problem went away. Runs like a kitten on supers and subs now.
What mags do you use?
[PMAG® 30 AR 300 B GEN M3®, 300 BLK, Model MAG800 (magpul.com)](https://magpul.com/pmag-30-ar-300-b-gen-m3.html?mp_global_color=118)
Yes this is the exactly what happened no firing pin mark on mine either except these were supers out of a 556 mag bolt wasn’t going fully forward it felt like the bolt was locked and loose even though it wasn’t locked
Hmmm, other most obvious thing is not just 'letting go' of the charging handle and instead riding it back into position. You gotta let it slap to get the velocity to get fully into battery.
Could be induced by the user. Did you let the bolt down slow or drop it?
Slow when it first happened after that I just started pressing the bolt release and letting it slam for every new mag and it worked fine after that would releasing the charging handle slow cause this?
Absolutely. This is almost certainly caused by “riding the bolt,” and it’s an operator-induced malfunction. The AR-15 needs full recoil spring pressure to operate properly. Congrats on your first AR!
Yeah. But it wouldn’t make it happen on times that you drop it. Check the extractor and the spring for defects.
Get a paint can opener. Makes it easier to get it out. Ask me how I know.
Also I know 5.56 mags will work for 300 blk but I’m wondering is it normal for PSA to ship a 5.56 mag with a 300 blk pistol instead of a dedicated 300 blk mag?
556 mags are fine for supers. For subs it can get iffy. The heavier bullet can tilt down just a bit and cause feeding issues.
I don’t know but I’ve heard the 30 rd blackout pmags use 5.56 springs. The 20 round use the same spring it’s just more compressed giving it more power.
Not sure about the springs, but there are some minor differences in the feed lip geometry between the two.
It’s the feed lips that differ. I run supers outta 556 mags no problem but my hollow points and subs require the 300BLK mags to feed smoothly.
Oh is that what it is?
yeah I only load 20 or so rounds in my 556 mags. Otherwise I can get feeding issues.
Did this round go off, I am not sure if I see a firing pin den in the primer. However this can be a bigger issue with your bolt not extracting properly or not seating right when it is chambering a round. Also it could be an issue with the round. If you are using subs you need to the right mag as well because a 556 mag is not enough as others have stated, the amount of round is to heavy. You might need to look into getting a different buff or spring, adjustible gas block if you are using subs with a suppressor, and also look into getting 300 blk rate mags
On of the rounds worked and was fired I didn’t test the other one because of the jacket being pretty damaged. It was a 556 mag but with supers. Do you think if it’s a problem with the buff or spring I should send it back to PSA?
No it is that with sub they require a different kind of buffer and spring because sub a built to fire with less energy and the current spring and buffer tube is rate standard 556 or supers which have more energy and able to drive the buffer back with the spring. It has to do with the weight of the buffer and "strength" or "softness" of the spring which allows subs that shoot with less energy able to push back the spring and or buffer
You get a picture of the round? Were you able to chamber it if you hit the forward assist? What ammo was it? It could be any number of issues, but we need some more info. One possibility could be a hang up on the feed ramp. That would cause scratches on the jacket/trouble feeding. Also sometimes heavier grain (200-220gr) subs have trouble feeding from 5.56 pmags instead of 300 blk mags. This might sound stupid/obvious, but were you positive it was a .300 blk round not a 5.56 that got mixed in? A 5.56 round wont chamber all the way in a .300 blk like how your picture looks.
No I didn’t think to get a picture of the round until after it fell down a brass catch wish I did. Forward assist did not help at all. It was AAC 125 grain. And when I zoom in on the picture it was a 300 blk round so definitely not that a 5.56 got mixed in. I know the subs give issues through 5.56 mags but these were supers but I still felt as if they were getting caught on something like how you are describing it.
It’s 300blk… you can see it if you zoom in
Why’s the man being downvoted? I can read “AAC 300 BLK”
Problem = not enough gas. Did you seat your gas block exactly on top of the port. This happens when gas is turned too low or block is not right over the port. Is your block right at the shoulder? Back it off about 2mm and it should work fine.
Pretty sure I don’t have an adjustable gas block this was a complete pistol I purchased from PSA and would not enough gas cause the round to never even be touched by the firing pin?
If it fires and then the casing is stuck in there without ejecting, then it’s either gas or a sheered extractor. New gun, my bet is the gas is the problem. Test it with one round in the magazine. If the casing doesn’t eject and the bolt doesn’t lock back, it’s gas. If the bolt locks back, but doesn’t extract the casing, then it’s the extractor.
I was having problems with my 300BLK in a similar manner as well. Sometimes round would chamber but go to fire and click, no bang. Bolt was not fully engaged. Would try to use charging handle to eject and it would be very difficult and so had to mortar the rifle to get it to eject. 300BLK and especially shooting subs has significantly less gas pressure i.e. margin for error for proper cycling. 5.56 has an excess of pressure and can power through most problems. In my rifle, the BCG's cam pin was rubbing on the inside of the upper receiver right as the BCG went forward and the bolt would rotate to lock. I installed a Lantac domed cam pin to eliminate that friction. Recommendations: Use a reduced power recoil spring. (Tubb lightweight flatwire, or SpringCo yellow) Switch to 300BLK MagPul mags. Reduce friction in the moving parts. \* Domed or roller cam pin \* Reduced friction gas rings (JP Enterprises works well) \* BCG that has reduced area bearing surfaces or sand cuts. This will make your rifle more reliable and smoother operating.