AR 15 problem


January 20, 2012, 03:37 PM
I recently completed my first AR build using all spikes tactical components. Took it to the range today for the first time and ran into some issues and was wondering if anyone has a idea as to what a solution may be. It ran the first clip through fine then around the 25th 30th round it would fire the first round and then fail to fire the next chambered round. I tried two different kinds of ammo ( American Eagle and PMC) both with the same result. Each time when I ejected the unfired round , the primer would be dimpled but obviously wouldn't fire...

I know this may be vague but any help or advice anyone could offer would be appreciated..

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Mac's Precision
January 20, 2012, 03:58 PM
Check your basics.

Compare the primer dent of fired rounds to the dent in unfired rounds. Are the fired dents MUCH deeper indicating positive ignition as opposed to shallow taps on the unfired cases?

Check for firing pin freedom of movement. Examine the firing pin hole in the bolt and assure there is adequate clearance for the pin to freely move through.

Check firing pin protrusion.

Check headspace.

Check hammer travel and freedom of movement.

What brand / weight springs did you use in the lower?

What trigger group components?

What firing pin?

January 20, 2012, 04:59 PM
check for crud/burrs inside the bolt face

January 21, 2012, 04:08 PM
Does the hammer fall when you pull the trigger or is it not cocked?

January 21, 2012, 08:11 PM
I think CCW might be onto it. Sounds like the disconnector might not be working and the hammer following the bolt down.

January 21, 2012, 08:18 PM
Is the spent case always ejected?

January 21, 2012, 08:24 PM
check the unfired rounds in another rifle

they may not be sized right and the bolt can not go into battery, hence the firing pin not reaching the primer

January 21, 2012, 08:31 PM
This same thing happened to me (dimpled primer but no bang) and I found I had installed the hammer spring backwards, enough force to dimple but not to go boom. if you do a google search for "ar15 hammer spring backwards" you will get a bunch of posts from ar15 dot com about it with some pictures. My trigger pin also worked out because of it. as soon as I switched the spring around I had no issues.

January 22, 2012, 08:31 AM
First thing to do is check the hammer spring. Fairly common on first time builds.

Legs over the top.

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