So the second time I was cleaning my 6920 I forgot to put the firing pin in before I assembled everything. 
Take it easy on me, I’m new to ARs. As you can imagine this is a problem. The bolt won’t go fully forward so I’m unable to strip it down again. Any suggestions short of paying someone to fix it? Thanks guys!
You will need to get a dental pick or similar and try and turn the cam pin. It will be a serious PITA. You may also try shaking it vigorously which may allow it to rotate. That’s all that comes to mind at the moment.
Thanks bud, I’ll see what I can do.
You da man! If you’re ever in Anchorage, beer’s on me.
If you un-pin the upper from the lower, both front and rear pins, you should be able to slide it forward enough to remove it.
We all make mistakes, and have all been there/done that. 
Since you say you are new to ARs, and this was your second time at disassembly/reassembly, I’ll ask the question no one else has yet asked…Do you have an Operators Manual that you can refer to?
I did that one time with my LR308 when I was still new to the AR platform. I was loading ammo for it and was checking the COAL (Cartridge Overall Length) by doing a chamber check. I took the firing pin out to be “safe” not realizing that the cam pin would now be free to rotate and bind up in the receiver. I pulled the charging lever back and let 'er fly home. Bad move. Needless to say, the chamber check “failed”. The bolt went into battery just fine but when I tried to extract the round…NO GO. I thought that the COAL was too long and the projo was just stuck on the lands so I proceeded to butt stroke the gun on the ground with my hand pressing down on the tack latch…standard procedure for extracting an improperly sized round. However, NOT the standard procedure for un-fucking a jam due to a rotated cam pin. At this point I still had no idea that it was bc of the cam pin, not the round. So I kept butt stroking, even harder (wow, that sounded kinda gay). Eventually the bolt went back and the round came out but not without slightly dinging up the inside of my receiver where the cam pin was bound up. Purely cosmetic, didn’t really hurt a thing. Lesson learned though. My situation actually inspired some friends who are in the manufacturing business to make a short firing pin for the AR that allows the user to do function checks safely.
BINGO! I was just about to say, read the operator’s manual thoroughly, and practice assembly/disassembly until you can do it, without referencing the manual.
Not that I would ever leave a pin out after cleaning (:eek:), but just wondering which method worked. The pick or the shaking?
Yep, I bought it brand new so I have everything. I read it thoroughly but I’m more of a visual person so I went on YouTube and found some professional cleaning videos and went step by step with the video the first time. Second time I thought I had it pretty well figured out.
What happened is the firing pin was sitting next to/under the Q-tips I was using and I just never even saw it. I knew I was missing something but couldn’t put my finger on it.
I took a plastic clicker pen and pushed on the (digging up manual to find correct term) bolt locking lugs to rotate it enough that it turned and the bolt went forward. I was then able to disassemble the rifle and fix my moronic mistake.
Tried that but the rear pin hole on the upper wouldn’t allow it to move forward.
I believe that he said that the bolt wouldn’t go fully forward. That means that the bolt carrier probably was still partially to the rear which means you can’t remove the upper.
That too.
Excuse my ignorance, but I don’t understand why not installing the firing pin would cause it to not lock/unlock.
I guess I never realized the cam pin actually interfered with the firing pin.
The firing pin passes through the cam pin. If the firing pin is missing and you install the BCG the cam pin can turn freely and not within the track as it is designed.
I’m going to have to try this just to say I’ve done it.
Maybe be tomorrow’s afternoon project.
I’m new to the AR platform and let’s hope I don’t do the same.:eek:
I have seen this many times. A good method of prevention is to shake the bolt carrier group prior to inserting it into the weapon. This will usually let you know if it is going to stay in.
Also, be careful before to ensure the firing pin is all the way in before you insert the firing pin retaining pin, if you don’t, the firing pin can still fall out.
I think the best way to prevent these things from happening, is to simply read the Operators Manual. Become familiar with the correct nomenclature of the individual parts, their purpose, and how they interact with each other.
As mentioned above, if you are not completely comfortable with the disassembly/reassembly and function check of the weapon, without having to consult the Operators Manual, then have the manual open in front of you, so that you can reference to it occasionally to prevent making a mistake.
There are the little tricks like we all learned in Basic Training, like inserting the Firing Pin Retaining Pin, then shaking the bolt to ensure the Firing Pin does not fly out. Or pushing the bolt into the carrier, then flipping the carrier to extend the bolt. These are all things I still do to this day out of habit.
But again, the best way to prevent these things from happening, is to simply read and become familiar with the Operators Manual.