First let me say I'm pretty new to AR's. I assembled a couple with kits and have been shooting various 55gr ammo. Both are marked 5.56.

So yesterday I took my boys and nieces out to do some plinking. At some point during the shoot one of the kids loaded some ammo that had been loaded for a bolt gun in the AR. It's a 40gr Nosler BT lead free over H335, CCI primers. They fired about 10-12 rounds and had a jam. I saw them drop the mag and start trying to pull the handle back, no go. I went to them and took the rifle to the truck. I don't know for sure but my son said he thought it jammed loading a round not ejecting. So may be dealing with a live round.

The thing is [i]really[I] stuck. I put quite a bit of pressure pulling back on the charging handle and neither the carrier nor bolt show any movement. I even tried hitting the forward assist with the heel of my hand and it didn't move. So how do I get it apart? Is H335 a bad powder for AR's? Nate

This is common when the shoulder is not bumped back enough.  It is likely a live round and chambered but the headspace of the brass is too long.  Any ammo for a semi-auto gun must be full-length resized every time to be reliable, or you get this stuff.

To clear the weapon, collapse the stock fully, place your fingers on the charging handle, and "butt-stroke" the weapon to the ground, with the weapon completely vertical, impacting the ground on the buttstock, at the same time pulling towards the earth on the charging handle.  Don't be gingerly, this takes a firm hit.  This gives you the momentum of the weapon, the carrier, and your arm while pulling on the charging handle at the same time.

This, and keep all body parts away from MUZZLE end of gun when doing this.

http://www.youtube.com/watch?v=kzBdyubc0Uk

Thanks Guys, I usually do full legth size so not sure what's up with them. They didn't malfunction out of the mini, but this bolt is stuck for sure. Will do this when I get off work tonight.

I had a friend who swore his were FL sized.  It turned out he was not turning the die down far enough to "cam" into the shell plate, and when I put his in a case gauge, they showed to be just a TAD long, and that is all it takes.

First make sure your rifle is on safe and pointed in a safe direction.  If it is a collapsible stock fully collapse the stock.  Then ensuring the muzzle is clear from YOUR face and in a safe direction away from anyone or anything you may injure/damage mortar that bad boy on the ground while trying to pull the charging handle to the rear in an attempt to extract the round that is lodged in the chamber.  This may take some effort.  Do this until you get the BCG moving.  Once the BCG is moving if the round is still stuck you will have to attempt to remove it with using a stuck shell extractor or just with your BCG (depends on what you got going on) or you can elect to clear it yourself or take it to a gunsmith for guidance.  Most importantly be safe, this is a drill that won't allow for complacency.  If you are not familiar first and foremost is safety.

I used the method described & linked to on you tube and it ripped the rim off the case. It did free the bolt though. I had to drive the shell out. It damaged it pretty bad but from what I saw it looks like a piece of brass may have been wedged in the chamber against the case near the shoulder. Don't know where that little piece may have come from but the AR isn't as forgiving as the mini. They shot most of them in the mini, until this happened and I stopped them. The rotating bolt definately requires a shorter case.

Thanks all for the tips.

If you got the mag out, and can open it up, try using a LARGE flat blade screwdriver to pry the bolt back. I have also been known to use a cleaning rod with no tip to help unstick the case. Haven't had to try it on a live round but....

I'm in the same position as OP.  I got hte upper separated and have used a 30 call steel cleaning rod (300BLK) and it ain't moving.  Looking at the bottom of the rear receiver, it looks like the rear of the bolt carrier is a bit off center and canted to the right.  My round didn't cycle forward fully, but was able to get it to chamber with the help of the FA.  Fired the round, and haven't been able to get the CH or ABCG to move much.  It appears like the bolt is still cammed closed.  Any ideas?

Did you buttstroke it?

I buttstroked it, used a .25" stainless rod to hammer the hell out of the inside of the empty case, etc.  After reading this thread, went home and went to prying on the bottom of the bolt with a long Phillips head screwdriver- viola!  Evidently, the case was not quite ALL the way in the chamber and the last 1/4" of the case was swelled out, probably about 1/4" wider OD at the head than right in front of the swelling.  Lesson learned.

Mine did this once and it ended up being two gas rings that got bent up and shoved in between the bolt and bolt carrier. I sent my stag bolt back to Stag and they sent me a new one within days stating that there were burrs in the Bolt carrier that caused it.