New AR build has light strike problem


Took my rifle to the range yesterday for a first run and it frequently light striked 1st 2 rnds of mag and then another or so part way thru the mag. The range officer a 20 yr marine broke the rifle down for inspection and found no obvious reason for it. Got it home broke it down for a full inspection and every thing looks in order , firing pin protrusion good , trigger assembly appears good. So what might be a real starting point to figure this problem out ? Running a palmeto state premium BCG and CMMG lower parts kit.


Did you look to see if the primer seated deeper in to the case on those rounds?


I got a “CMMG” parts kit online that turned out to be bogus Chinese knockoff parts. The springs in the kit were pure shizit. Check the hammer spring, make sure it’s a good one.
Mine actually bent and didn’t have enough strength to drive the firing pin home.


Bad ammo maybe?


I wold have to see all the parts and ammo.
Some Russian ammo has thicker primers.
The hammer spring is a good thing to look at. Measure the firing pin and check your measurements with a known good one.


Start with the ammo, try a different brand. This is of course if you took the BCG apart and cleaned it up real good before using it.


I’ve had this happen on a couple of my 7.62 x39 ammo, Light Strike because the primer pushed down into the pocket further. I refed into the gun and they went off fine.


Ammo run fine in my other rifle in same range visit. So Ill check the measurements with my other rifle when i clean it tonight ( already measured the faulty rifle ) Dont realy have a way to check springs other than by feel comparing with another rifle. Hate to be swapping parts for a hit and miss fix and run to the range each time.


Can you change the springs at the range?


Make sure the hammer spring is installed in the correct direction. Can be installed backwards.


Check your headspacing as well


Probably but I just got finished cleaning and measuring the BCG on the good running rifle and the specs are exactly the same as the problem rifle. So next was testing hammer tension by hand and it seems that my new build has almost half as much tension as my good running rifle so next I`ll get a new hammer spring rather than rob one from another rifle for hit and miss testing


Did your firing pins match up in length?


Exactly all bolt measurements between both rifles were the same including firing pin protrusion. Believe it may be weak hammer spring now


That ok because it’s an easy and cheap fix Brother!


I got mine from my LGS package looks genuine. Checked the hammer spring tension against my other rifle and it seems to be almost half so I believe that will be my next move.


Hi Tribes,
I see that you’re not new here (joined in May) but this place has really picked up since then.
Since this is your first post we’d like to encourage you to stop by the introductions section and tell us about yourself.

This like is to the updated “What to expect” topic.

But welcome back and we look forward to your input.


Thanks glad to have another good place to visit. I post sometimes on Firearms Forum good bunch of guys over there too . Got a little humor also. I`ts good to have a place where people can trade info and and show off their toys.


Good call, may be a legit kit with a bad spring too. My kit looked very legit, but I noticed a few things that seemed “off” and after really checking things over, I found numerous small details that just didn’t jive with my previous CMMG kits…the springs were the dead ringer.
I bet that new hammer spring will cure your issue.


I’m sure it wont hurt to have an extra hammer spring laying around anyway.