Problem with my AR15

Bak Dur

Bak Dur

CGN frequent flyer
Super GunNutz
Rating - 100%
135   0   0
Location
Mississauga
I have a DPMS oracle that has been giving me problems and I have no clue what else to do.

The rifle is not cycling. It looks as if the bolt is not even attempting to move back when I fire a round (so gas isn't getting to it???). Originally I tried a few things and then noticed my gas block was lose. I bought a Gas Block alignment tool and I know for certain the block is aligned properly. The little piece of plastic was moving from the barrel to the block freely as I turned rifle upside down and right side up a few times. So after I realigned the block I fired 6 shots and not one of them cycled my bolt. Here is what I've tried, let me know if you have any ideas what else it could be:

I replaced buffer spring
checked my bolt and gas rings - look fine and bolt passes test of standing it up on itself
the gas key is properly staked/pinned and has zero wiggle.
I took gas tube out of gas block and made sure it was completely clear and reinserted it with new roll pin

Am I missing something? I did notice that these test shots were done bone dry. I cleaned everything and didn't really lube it up, but I don't think that would prevent the bolt from even slightly moving. I will lube and try on weekend with 2 different ammos' in case my Norinco Tuna Can 556 is crap, but I've shot it before no problem. Gun only has like 1400 rounds through it since new.

Any advice is welcome
 
I had that problem with a DA 556 from Canada Ammo. Tried everything. just as you have done.
Eventually I sent the upper back to Canada Ammo and they sent me a new one.
Never did find out the problem??
 
Loosen the two set screws on the bottom, push the gas block hard back towards the handguards and holding it there, tighten the set screws. Make sure the block is level, doing these two things will make sure the barrel gas hole in aligned with the hole in the block. Finally, what ammo are you using?

Scott
 
So I noticed it wasn't cycling and tried those few things first - changing buffer spring and checking bolt gas rings. That's when I noticed the gas block was lose. I used the Brownells plastic tool to realign them and it is sitting properly for sure. It's a plastic rod that fits perfectly in gas hole in barrel and will fall into and out of gas block when aligned. Then you push it out with cleaning g rod through barrel. I will try running it wet to see if that helps. I used to always run it wet but then switched to Otis dry lube spray. We will see if that helps.
 
Update in case anyone else has this problem. I tried a new BCG and AR worked fine so I looked closer at my carrier and that's when I noticed there as an obstruction in my gas key. I am thinking its a primer from my Norinco Spam can ammo that must have got in there somehow (the primers tend to fly out quite often). I have no clue what else it could be. Definitely not carbon buildup though, something is lodged in there good. ordered a new gas key for $13 bucks so should be good to go :)
 
Can't you just remove the obstruction. It would be easier than staking on a new key if you even have that tool ? Drill it out or dremmel .
 
I was going to try and drill it out but then someone pointed out it may have melted in there and bonded with the key so why risk it. I'll put the new key on and hopefully get a gunsmith to stake it for a reasonable price. Otherwise I can just buy the tool from Brownells.

MustangFrank said:
Can't you just remove the obstruction. It would be easier than staking on a new key if you even have that tool ? Drill it out or dremmel .
Click to expand...
 
Bak Dur said:
Update in case anyone else has this problem. I tried a new BCG and AR worked fine so I looked closer at my carrier and that's when I noticed there as an obstruction in my gas key. I am thinking its a primer from my Norinco Spam can ammo that must have got in there somehow (the primers tend to fly out quite often). I have no clue what else it could be. Definitely not carbon buildup though, something is lodged in there good. ordered a new gas key for $13 bucks so should be good to go :)
Click to expand...

Thanks for following up.

I'm interested to hear about the loose primers - Is this a widely reported issue?
 
Not sure if its a primer in there, but I can say that the Norinco Spam Can I've been shooting seem to have maybe 1 primer every 10 to 15 rounds come flying out/blown right out of its seating in the case. I find them everywhere in my range bag and case when I get home. I don't know what else could have got in there??? I rarely take the BCG out at all and when I do, I definitely do NOT stick anything in the gas key.

alpining said:
Thanks for following up.

I'm interested to hear about the loose primers - Is this a widely reported issue?
Click to expand...
 
I shot 6-7000 rounds of it a few years ago, with zero issues. Buddies shot more than me, with no problems either.

I'm not an expert, but it could be revealing another problem with your rifle: In a properly functioning firearm, the primer expands/flattens to fill the primer cup in the case after firing, sealing the rear of the case. Fired primers should look flatter than unfired. Loose primers are a sign of insufficient chamber pressure (due to low powder charges or failure of the case to seal properly in the chamber). It can also happen with reloaded cases, but that's not possible here, right?

Maybe early extraction, or maybe a problem with headspace or bolt face or something like that. Unless for some reason your ammo is extremely out of spec. But since I've never heard of this problem with this ammo before, I'd suspect a problem with the rifle.

Is the new bolt showing the same loose primer issue?
 
Haven't tried my new BCG yet. I tested the rifle with a buddies for like 10 rounds and didn't inspect those ones. I'll check this weekend with the Nickel Boron BCG I just rec'd :)

alpining said:
I shot 6-7000 rounds of it a few years ago, with zero issues. Buddies shot more than me, with no problems either.

I'm not an expert, but it could be revealing another problem with your rifle: In a properly functioning firearm, the primer expands/flattens to fill the primer cup in the case after firing, sealing the rear of the case. Fired primers should look flatter than unfired. Loose primers are a sign of insufficient chamber pressure (due to low powder charges or failure of the case to seal properly in the chamber). It can also happen with reloaded cases, but that's not possible here, right?

Maybe early extraction, or maybe a problem with headspace or bolt face or something like that. Unless for some reason your ammo is extremely out of spec. But since I've never heard of this problem with this ammo before, I'd suspect a problem with the rifle.

Is the new bolt showing the same loose primer issue?
Click to expand...
 
well. why risk it? I say why not risk it take a drillbit that fits it and hold it with a vicegrips and see if it will come out easy. your going to replace it anyways you say, why not take the opportunity to learn
 
oh yeah I am definitely cutting it open to see what was in there now that I ordered a new one. I am curious to see what it is and if it did indeed melt and bond with the frame. I'll post pictures once I get it done.
Mongo62 said:
well. why risk it? I say why not risk it take a drillbit that fits it and hold it with a vicegrips and see if it will come out easy. your going to replace it anyways you say, why not take the opportunity to learn
Click to expand...
 
You must log in or register to reply here.
Back
Top Bottom