I have recently aquired a pre-ban Colt,
excellent shape,
I had some failure to fires recently where the primer was dented but did not fire?  on a couple of these upon pulling back on the charging handle it did not engage the bolt. the handle came back but not the bolt. what causes this, the handle does not appear to be worn and it does not do it all the time?

Thanks

RAC

Since this is your first post, I will go along, but I am questioning where you have a AR-15 at all!!!!!!!

Unless this is a 9mm rifle, you have a real problem.  One the 5.56 AR-15 rifles, the cocking handle has a hole on the end that grabs the carrier key.  The gas tube runs threw the hole(like a guide) then the key goes into the hole, with the gas tube on the inside of it.

With the key/tube inside the handle end hole, there is not way that the cocking handle is failing to grab the key/carrier.

Pull your handle back, pull the carrier/bolt out, then pull the handle all the way back.  At the end of the rearward stroke, push the complete cocking handle down to have it glide down out of the retaining slot and pull the cocking handle.  Unless you have the wrong cocking handle, or the end of yours is broken, You have been dreaming again.

Know if you saying that the carrier is coming back, but is leaving the bolt in the barrel extension, then you have installed the bolt/carrier wrong, or your cam is broken and is not rotating the bolt out of battery.

As for your light hits, break the bolt down and check the firing pin channel. Chances are that it is full of fouling and needs to be cleaned.  The use of a Q-tip from the back end and CLP will do the trick.

Here is the repair manual:
old.ar15.com/books/TM9-1005-319-23.pdf

And since you have been stumped by the simple cocking idea, the user manual;
old.ar15.com/books/TM9-1005-319-10.pdf

P.S. Welcome to AR-15.com.

Dano

Thanks for the response, I had the weapon broke down before posting to check it out and I still
hope it was a dream, I couldn't see how it would happen unless the charging handle was broke. If it happens again I will get pics.

Thanks for the input on the repair manual sites. I have been using Scott Duffs book and it was helpful, but not in this dream.

With the firing pin question I have addressed some excess carbon there and will try it again this week ,

RAC