Ammo issue or something else?

[imku]

I'm currently in the 2k range of ammo usage, clean up after every range session and lube internals generously. I'm shooting AE XM193 55gr and within the last 300 rounds I had (2) failure to fire issues and the ammo has light primer strikes. When I pulled the trigger there a click but no bang. When looking, the bolt seems to be all the way foward (is there any way to tell besides visually?). I eject the round, inspect and reload and it shoots fine. Question is, (because I could not tell) do you guys think that the bolt was not locking all the way foward, or was it ammo induced? I think this is a minor issue, but i was just wondering if anyone can enlighten me. Google search didn't seem to help much this time .

 

[BHarada]

You can check the bolt by pushing it forward using the small scallop cut into it. If it moves forward and clicks into battery then you know that it's not cycling fully after firing.

Do the misfire rounds fire when you re-chamber them? If they do then I would lean towards a mechanical issue with the bolt/hammer. Have you done any work on the trigger group (i.e. lightening springs)?

 

[bobbyd3]

I had a similar issue when I first shot mine.

I figured out it was because I wasnt letting the chargeing handle snap back I was pulling it back and pushing it forward gently. Im new what can I say

Then went to shoot and Click. Eject the round it had mark where was struck but didnt fire. Ever since then I let bolt go and have had no troubles. The rounds that had light strike mark all fired when I re-loaded them

 

[imku]

First, thanks for the replys. Misfire rounds are DO fire when reloaded. The FTF (failure to fire) happened on the second round so I believe it has nothing to do with riding the charging handle foward. I have left the internals/trigger group all stock and plan to leave it that way for a while. What would be the issue with the bolt or hammer? I don't really know what to look for, and upon inspection prior to my cleaning the firing pin was free moving just fine. What else do I need to look at?

 

[SW Gun Guy]

I am far from the expert here. Does that ammo have the primers that are made for AR type rifles, i.e. slightly harder primers? If so, I would say that I would look for the pattern (2 out of 300) to get better or worse. Might just have been tough primers that worked the second time they were hit. I think statistically, 1 out of 150 misfires is not enough of a pattern yet to take any action. Just my $ .02

 

[imku]

I am far from the expert here. Does that ammo have the primers that are made for AR type rifles, i.e. slightly harder primers? If so, I would say that I would look for the pattern (2 out of 300) to get better or worse. Might just have been tough primers that worked the second time they were hit. I think statistically, 1 out of 150 misfires is not enough of a pattern yet to take any action. Just my $ .02

This is definatley something that crossed my mind as far as a low round issue/pattern count. Thus my post . I wanted to hear suggestions/recommendations to further my own knowledge on this type of issue so in the furture I can identify/diagnose it immediately. The ammo is AE XM193 55gr, which I assume have primers made for AR type rifles.

 

[oneyeopn]

is there any carbon or dirt build up on the firing pin shoulder face or inside of the bolt, that also might cause the problem.

 

[imku]

I definately had carbon deposits on the small flat surface areas of the firing pin, but nothing more than I usually see.... The BCG and bolt had the same amount of carbon as usual with everything still oily prior to my cleaning. The first FTF was at about 100 rounds in and after about another 80-100 rounds the second FTF happened. The more I think about it I lean towards what S&W GUY said and link the issue to ammo. Next range session I will use different ammo and post if i have similiar issues. Thanks again for your input guys