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Can a mag extension lead to light primer strikes somehow?


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Shot a 3 gun match today. Had some rifle issues.


Stage 1 - used a MFT mag, some people report bad issues with them, they've worked fine for me. I shot the stage without a hiccup.

Stage 2 - used my 20 rd G3 PMAG w/ a new Strike Industries +5 extension. Out of 8 rounds, only one round fired. The first shot did not fire so I stripped it and reloaded. Repeated a couple more times, and then it fired one. Then the problem repeated, and I just called the stage. All rounds seemed to have light primer strikes.

Stage 3 - used the MFT mag again, no problems.

Stage 4 - used my 40rd G3 PMAG w/ another Strike Industries +5 extension. No problems at all except for one double fire. 


Rifle has a Hiperfire trigger with < 1k rounds. New things that have happened since my last match are new loads, mag extensions, and a Odin Works Zulu 2.0 stock. I inspected the bolt, and everything seemed to be okay. I had also used the same 20rd G3 PMAG when I was developing loads though I only loaded 5 at a time. Any suggestions on what could cause this problem? When I did open up the rifle to see if anything was wrong, the buffer retaining pin popped out, but I don't think this would have caused the problem.

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Dude,  I think you have all kinds of gun/ magazine / ammunition issues.  The MOST likely cause of a malfunction in an AR, and I have to assume its an AR as you don't say, are magazines and lube.  Since you changed several items; I think the MOST likely cause is the ammunition, possibly the stock some how, and finally the magazine.  The magazine is last provided you have had those magazines run in that gun before.  


Magazine extensions COULD cause failure to feed issues if there is something going on w. the spring or its assembled incorrectly or its just plain full of crud.  


"No problems other than one double fire" is a BIG problem that needs looked into, you also need to make sure you did not simply bump fire the trigger which can happen.


Look at the ammunition again, are they really light hits or just firing pin dimples?


Excessive sizing can cause issues and create an excessive gap between bolt face and firing pin.  

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Stick to the magazine/magazines that work.  Next, compare the ones that don't work to the good one/ones and try to make them like the good ones.  (Lip width and how the follower works and anything else that seems different.

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