I'm having a consistent problem with my AR15. I am consistently getting rounds that do not go off.

I believe it's light primer strikes, but I'm looking for your guys input.

 

Build consists of:

 

Upper: Spikes Tactical 14.5" Midlength Upper with Dynacomp

Lower: Spikes Tactical lower with Daniel Defense Lower Parts Kit. Spikes Buffer Tube and Spring Set.

 

Ammo:

 

Tula Steel Case

Federal Brass Case

 

Take a look at the rounds that did NOT go off:

 

 

Here are some casings of rounds that did go off:

 

 

In today's session alone I had 8 rounds or so that had this issue out of maybe 50 or so rounds so there is definitely a problem.

Maybe about 4 out of 20 rounds the last time it was out.

 

Thanks for your help.

Ide bet its the cold. Primers become harder to ignite and lubricants become gooey and slow parts of the gun down. Could be either issue or both issues. Easiest way to solve it is use an AK

Did you lube the firing pin at all? Not supposed to and in the cold that can be the cause of the issue....

Dirty bolt carrier group of shotty ammo. Take the BCG apart clean everything then try again.

Could be the cold. But we have been shootin the last month is sub freezing temps with different calibers and have had no issues because of the cold.

Try a different firing pin (yours may a bit too short) and retaining pin.

 

People who shoot 7.62x39 steel case in their ARs (with standard .223 firing pins) have this problem.

I would throw those rounds away. I would go with heavier hammer spring. I had the same problem with my mini 30. Heavier hammer spring fixed the problem with my minI 30.

A friend of mind who is an armorer also suggested the hammer spring. Any thoughts?

 

It was very cold, but I had this issue in an indoor range only a couple weeks ago.

 

Granted I have not given it a super thorough cleaning, but there are less than 250 rounds

through the rifle so I don't think that's the issue.

I had some light hits with my pistol. Took out the firing pin and there was gunk on it. Cleaned the firing pin and no more problems. I'd follow the advice to clean the BCG first before messing around with hammer springs. Relube with a light oil if you're using a thick lube now.

It's hard to tell, but it looks like the primers on the "bad" rounds are set too deeply into the case.

 

Run a finger over them, are the primers flush with the brass or do you feel a "step" where the case head is higher than the primer?

It's hard to tell, but it looks like the primers on the "bad" rounds are set too deeply into the case.

 

Run a finger over them, are the primers flush with the brass or do you feel a "step" where the case head is higher than the primer?

 

Not a bad call but I'd say the issue is too frequent to be an ammo issue.

 

I'll try cleaning the firing pin.

 

I do like the AK solution. LOL!

Ammo with a plus sign in side of circle on case head is NATO Spec with hard Mil Primers. Hammer spring or firing pin in the problem here. Also, russian ammo has very hard primers.

 

Would your hammer spring happen to be painted yellow? If so, JP reduced power springs may be installed in FCG. Then this is the problem. Change to full power springs if you plan on shooting Mil-Spec Ammo. New Springs can be ordered from Wolff Springs.

If I'm not mistaken the spring came with my Daniel Defense lower kit.

I don't know if anyone knows what spring comes with that kit.

 

Will a stronger spring effect trigger pull?

Three Springs in FCG. Hammer, Trigger, Disconnector. I don't know what DD is using for spring strength, would assume MIL-Spec. Try cleaning bolt carrier first. Get some auto parts brake cleaner and spray down the firing pin hole in the bolt carrier and use a small caliber cleaning brush to clean out. Maybe some left over crud in there. Spray firing pin also.

Make sure all parts are installled properly in BCG. Try again. If no better, I would look to make sure hammer spring and trigger spring are installed properly in lower. Are they in correctly? Reference pictures on AR15.com in the manual section. It is possible for them to be installed improperly causing light hammer strikes. Good Luck.

Not a bad call but I'd say the issue is too frequent to be an ammo issue.

 

I'd say the frequency points directly to an ammo issue.

 

If it was a cleaning issue, the problem should get worse as you shoot and get the gun dirtier.

 

If it was a gun issue, the rate of malfunction should be much higher.

 

If it was a cold issue, it should be resolved when the gun warms up by shooting it.

 

I just got back from a 3 day carbine course where I was one of 18 shooters participating. I personally fired 1132 rounds of 5.56x45. The other shooters fired about the same. That is a lot of rounds downrange. 1 shooter on the line was shooting PMC ammo. He had at least 1 malfunction related to this particular issue in every magazine he fired through his BCM EAG 14.5" midlength.

 

At least 3 other shooters had identical problems with some steel cases ammo (I can not remember the brand) and some Federal XM ammo.

make sure your hammer spring is on right...

TRIGGER ASSEMBLY

 

PARTS: Trigger, Trigger Pin, Trigger Spring, Disconnector, Disconnector Spring

TOOLS: 5/32" drive pin punch

 

 

• Shoulder trigger spring onto trigger with ends of spring forward and under.
  
• Install disconnector spring with the wider portion of spring down towards trigger and push until it locks in there.
  
• Position disconnector on top of trigger, where trigger pin will hold both in place.
  
• Insert trigger assembly into receiver.
  
• Insert trigger retaining pin through receiver, trigger, and disconnector. The trigger pin has 2 grooves in it; one in the middle of the pin and one off to one side. It does not matter which way it is inserted, though common practice is to insert from left to right, with the groove to the left.
  
• Insert hammer pin from opposite side to help align things as you push the trigger pin in and the hammer pin out. You will have to push down on trigger assembly to align the holes and get the pin in all the way.
  FUNCTION CHECK
  
• Make sure that the trigger pivots smoothly when depressed.
  
• Verify that the disconnector pivots when pushed.
  

 

HAMMER ASSEMBLY

 

 

PARTS: hammer (with J-pin installed), hammer spring, hammer retaining pin

TOOLS: 5/32" drive pin punch

 

 

• Install spring onto hammer, ends of spring to rear and shoulder on back of hammer.
  
• Install hammer in receiver with feet pointing rearward away from hammer
  
• Use 5/32" punch to retain hammer in place as you insert hammer retaining pin.
  
• Like the trigger pin, you may have to push down and align the holes perfectly in order to push the pin in all the way.
  
• Ends of the hammer spring will rest on top of the trigger pin, with one end in the groove on the trigger pin.
  
• Inserting the hammer pin may require some effort, as the J-pin in the hammer will catch the grooves in the pin.
  FUNCTION CHECK
  
• Verify that hammer locks to the rear when pushed back.
  
• Verify that hammer pivots forward when trigger is pressed.
  
• Without releasing the trigger, push the hammer back again and verify that it locks (caught by disconnector).
  
• Releasing the trigger should not cause the hammer to pivot fully forward (caught by trigger).
  
• Hammer will fall when trigger is pressed.
  

<a name="selector">

I won't rule it out but it's two different types of ammo.

that's the only reason I'm thinking it's something else.

If I'm not mistaken the spring came with my Daniel Defense lower kit.

I don't know if anyone knows what spring comes with that kit.

 

Will a stronger spring effect trigger pull?

 

Now let's talk...

 

#1 You are dealing with two of the hardest primers available. And shame on you for shooting steel cased but that's another issue.

 

Not an ammo issue.

 

And I'm biting my tongue regarding all these off the wall posts.

 

#2 It's a new rifle you assembled. Your LPK was packed in a preserving oil, did you degrease it and relube the pivot points with a very light oil? You should have.

 

#3 I doubt you have a bolt issue, but that should have been degreased and re lubed as well.

 

#4 Could be a faulty too light hammer spring to compound the other stuff.

 

#5 Yes a heavier hammer spring will effect your trigger weight.

 

If you fired it indoors I'd clean it (degrease) and try it again. If it F's up indoors you have a spring problem. If it's only in subfreezing weather it's oil.

 

That's why I ****. You have to be careful when you assemble, it's a machine and has to be viewed as that and not an Erector Set.

What is your firing pin protrution? Should be around 0.032 to 0.038.

make sure your hammer spring is on right...

 

Yep, I would bet that the spring legs are under the trigger pin

Yep, I would bet that the spring legs are under the trigger pin

 

That would be a shame on you moment!!!

I didn't assemble it and to be honest I don't know much bout ARs.

I'm gonna have it looked at next week by an armorer.

 

This is all good info though thanks. Learned a ton.

 

I'll update you guys once it's looked at.

Don't necessarily need to have it looked at by an armorer - just have it looked at by someone who's done ARs

Did you lube the firing pin at all? Not supposed to and in the cold that can be the cause of the issue....

 

I'm going to go with this^

 

That pin needs to be clean.

A friend of mind who is an armorer also suggested the hammer spring. Any thoughts?

 

It was very cold, but I had this issue in an indoor range only a couple weeks ago.

 

Granted I have not given it a super thorough cleaning, but there are less than 250 rounds

through the rifle so I don't think that's the issue.

 

A friend of mine had a problem like this after he built a lower, his hammer spring was backwards he turned it the right way and fixed it.

Yep, I would bet that the spring legs are under the trigger pin

 

First time I built a lower, I did just that!

Just a shot of the inside of the lower and the hammer spring. I don't know if this pic reveals

anything, but let me know if you see anything that is off. I don't know how it's supposed to

look.

 

Looks wrong ...no ?

Hammer Spring in upside down, reverse so spring legs come off pin from bottom not top

See diagram I posted previously from Arfcom, you'll see difference.