Just bought my first ar 15. Dpms Oracle yea I know shoulda spent more. I got it oiled it and shot it maybe 50 rounds first day. And 60 the next. After that I would only short stroke. Ive tried oil and diffrent bullets.  The green tips come the closest to not stroking. They will eject but not chamber a new one. Cheep ammo wont even eject. I did shoot a few round the second day from a shooting bench.  But why now. After it worked fine

Loose gas key, and loose gas block would be the first two things I checked.

If its a factory rifle they should fix it, it could be a trivial repair and not worth the trouble of dealing with the manufacturer.

Simple searches would find you a few hundred threads where all the troubleshooting for short stroking has been covered in exhaustive detail.

Obstruction in the gas port? Perhaps gas block is not set properly, the few rounds you fired were enough to clog what little opening there was.

See ive done alot of searching and the block and keya are properly aligned. Its like it just froze up. My aks havent done anything like this or the m14.

Start by scrubbing out the chamber with CLP and a chamber brush, mop it out, and dry with patches. Lube the carrier rails *generously*: you can wipe off excess throw-off, but if it's not wet during break-in, the increased friction may cause malfunctions. Also, confirm tightness of the gas key screws visually, by observing whether they have turned relative to the staking, and with a hex key. Lastly, full-power 5.56 ammo is best for the first few hundred rounds, until everything is run-in and smooth.

HTH

I guess when I shot it from thw bench the stock taking all the recoil caused the gas key to get a tiny chip. Cause its missing a tiny spot

Cause I cleaned the gun with rubbing alcohol like I read. And then used mobile 1 15w 30. A friend Told me that power steering is better.

Alcohol and 15w 30?  Clean everything with a good CLP and lube generously with a good gun lube.

I think you still have other problems with it.

Pic of BCG

If it's new I would call the manufacturer at this point.

don't forget that the inside of the bolt carrier and the bolt are the essential working parts of the AR15 gas system. make sure the inside of the bolt carrier is clean and smooth, and then check the rings on the tail of the bolt. if everything looks good, insert the bolt into the carrier, hold the carrier vertical with the bolt down and see that the bolt doesn't fall out. also the bolt should be able to move within the carrier with a bit of force. the bolt is the piston in this system, it needs to be tight enough to prevent too much gas blowby, yet not too tight to move. these systems like to be run "wet", find a tiny plastic liquid dispenser, fill it with oil, and every 50-100 rounds, squirt a bit of oil into the bolt through the gas ports in the bolt carrier. the best part of this is it only takes a second because the ports are easily visible looking at the bolt through the ejection port when the bolt is forward. your rifle, being new, probably has some tool marks and tight tolerances that will polish up with use.

make sure the gas check rings are not lined up as well.

TXL

 While still commonly taught and in the TM, this isn't an issue.  The gaps in the gas rings are compressed when the bolt is inserted into the carrier.  The rings don't stay in the same position while firing.  Even if you manage to line up all the gaps in the rings, it will function.  Even with just one or two rings, it will function (obviously not recommended!).    

Rubbing alcohol?  Where did you find that that bit of gun cleaning wisdom.

As for the rest of that, I think you need new (smarter) friends.

Yes, you need smarter friends who use Ketel One Vodka!  One for you, one for the gun.  

Seriously, If I need to rinse things off I use brake cleaner spray.  But for lube I am an old school CLP guy.  The other lubes can be good, and i have a friend who swears by Mobil 1, but CLP is very consistent and predictable and a good place to start.  Even the high speed low drag shooters have a can of CLP close by.

I had the same thing with a new AR once and we took the extractor apart and cleaned that sucker out real good. There was a very tiny bit of packing grease or something in there and I swear that was causing the malfuncs.

For some things a polar solvent is better. High percentage rubbing alcohol, or denatured alcohol, works well at removing the typical new gun preservatives, cosmoline, etc.

I too recommend doing the basics like checking your carrier key. Don't let the gas key bolt punches fool you. They still could come loose under usage like you describe and cause a leak. Have a smith that knows about AR's tighten up the bolt to the proper inch pounds! Also use some sort of CLP and brush clean the chamber well. After that if it still short strokes then investigate leakage at the front sight area but that's small odds.

Durango

I just solved my short stroking issue on my Recon 16.   The key was leaking which I could see when blowing through a straw with a little oil around the key.  I could see lots of bubbles.  After getting a replacement carrier from DPMS for my new Recon I noticed the staking was exactly the same - not properly staked.  I was able to remove the gas key screws with no resistance.  I sealed the key to the carrier with a little Loctite Hi-Temp.  No more bubbles. Now it fires all types of ammo with no short stroking, FTF's and locks back the bolt on an empty mag.

No_Calvary,

I'm glad everything worked out for you. From what I was told when sealing the gas key is to use some sort of gasket seal and then torque the gas key bolt to I think is about 55 inch pounds and punch to hold those bolts in place.

Like mine the smith saif mine was a little loose so he redid mine. Towards the end of the month I'm gonna get a chance to retry mine at the range. Cross you fingers mines works fine otherwise it's another trip back to the gun smith for me.

Impala

What does the fired brass look like? Splits or primmers falling out?