Lucky for me that it happened to someone I was with. After pulling real hard on the charging handle we were able to get the round out of the chamber. Still not knowing what it was, we tried putting my BCG in his gun but that didn't help either.
He went to see Wes (Sagewa) who pulled out a case gage and he quickly saw what the problem was....

It sounds like you guys are describing this stupid douchebag:
http://www.waguns.org/viewtopic.php?f=74&t=6978

The jam round I used CCI #400 small rifle primers, A2230 23gr, 55gr bullet. LC 5.56 Case, length 1.754. it seems the Primer does have a tiny dent in it. All my reloads are once fired brass, new fired by me. cleaned with walnut and corn until they shine better than new. If they need it I blow them off with compressed air but usually don't need it..

I bought a case trimmer a couple months ago but haven't needed it..

I think I do need a go-no go gauge- a LE wilson gauge .223 as you say.

Most if not all the primers cycled out of an AR platform without being fired have a small dent on the primer, due to the floating firing pin.

Have to ask though, are you sure it was a slam fire and not a bump fire? I have a light trigger on one of my lowers that if I do not follow through well, I can get a couple out in short order........

yes I am sure, it was instant, sounded as fast as full auto when bump fire is about half the rate as full auto.,

On slam fires or unintentional bump firing, make sure a hammer or trigger pin hasn'walked out and only in the hole on one side of the lower.

Had a partly empty mag empty itself one day due to this.

Nope, Classic was describing me. For some ungodly reason, I resized a whole bunch of 223 brass without camming over the press, so the shoulder was too far forward. Duhhh! I know better than that. It jams the round in there good and tight. Case gage!

I have taken the gun back out to the range and it worked great with factory ammo, shot 40.
I shot some reloads, only 1 in the mag at a time. It was slow going but I didn't have any problems shooting about 40 of them also.

I was very surprised at this gun though, it was the cheapest I could make with the cheapest blem lower from SAA, a PSA cheap complete upper with charge&handle $199, a cheap 4x scope. I rested it on a sandbag and at 100yd it was within a a couple inches (4 total) shooting it as fast as allowed, 1 a sec. At two hundred I couldn't focus on the bulls-eye cause the scope isn't good and neither are my eyes but I hit the target every time with only one flyer at the top but still in the target just an inch out of the circle. not bad for under 450.

I want to get a 3x9 for my other AR that has a bull barrel add see what kid of accuracy I can get from both of them, I hope the bull is better cause it weighs a lot more.

The range I am a member of is only 200 yd but a couple times a year they open it up to 600yards for 4 hours so I'll have to find somewhere else close that goes out to 300 maybe try 500. My neighbor was shooting 1000yrs last month his wife told me. I would need a 24x to even see it....lol

I'm going to get a gauge and hope my reloads work good it a full mag.

Thanks for everyone's help !!!!!!!!!!!!

Had the same problem with rounds stuck in the chamber. I use CCI 450 primers so no slam fires experienced so far.

I was crimping and bullet seating in same step with Lee 223 Seating Die. Troubleshooting revealed that I collasped the shoulder on a couple of rounds that must have been longer than the others. Starting crimping with Lee Factory Crimp Die after bullet seating step. Also checking each round with go/no gauge at resizing step and after crimp. No problems since this new crimping and QA checks.