New Diamondback AR question

[Mgderf]

My nephew called a while ago and said another nephew had just purchased his first AR15, a Diamondback .223 New in the box.
He said they were having problems.
I asked what was going on and he said that it would not even fire the first round.
Try, and try again, he said the firing pin was not even putting a dent in the primer.

I asked the nephew on the phone if he had his AR there and he said yes, so I suggested that they swap bolt carrier groups and see if it would fire.
Success! It fired each and every time tried.

I told him to take it back to the gunshop, and they did.
The smith at the shop told them that "the spring in the firing pin channel was getting in the way".
Nephew said they had it running in less than 2 minutes.

I have never heard of a firing pin spring in an AR15.
I thought they were all free-floating firing pins.

Is there a "new" design I was not aware of?
Would this be an attempt to mitigate the chances of a slam-fire?

I'm glad I could help him figure out the issue on the phone, but I'm still a little confused.
Not like that's something new...

 

[edwea]

Could it be that he meant firing pin retaining pin? Being new to the platform, I can see how he might have heard "spring" when the Smith said "pin" or "retaining pin". Just a thought.

 

[Mgderf]

Not sure. I wasn't there.
I only talked to him on the phone.
I don't really see how the firing pin retaining pin could "get in the way" of the firing pin, but that's a thought.

I'll need to tear that Diamondback down to take a look at it.
At first I thought he might have a short or broken firing pin.
I was confused when he started talking about a firing pin "spring".

 

[1mil-high]

I have never seen a true AR platform rifle to have a firing pin spring. That being said if the firing pin retaining pin were inserted ahead of the first nub on the firing pin it could prevent the firing pin from striking the primer. The firing pin would likely just fall out of the BCG if this were the case though.

Not sure what the shop would be talking about.

 

[Gabriel]

I have never seen a true AR platform rifle to have a firing pin spring. That being said if the firing pin retaining pin were inserted ahead of the first nub on the firing pin it could prevent the firing pin from striking the primer. The firing pin would likely just fall out of the BCG if this were the case though.

I'm going to guess this was the problem and the OP's nephew heard/remembered it wrong. That would be easy to do if you aren't familiar with the platform.

 

[Mgderf]

Without being there, I can't say, but this was a factory built rifle, new in the box, sold through a reputable dealer.
That said, I have seen some real pieces of work come straight out of the factory.

I don't believe I've ever seen a Diamondback AR in real life.

 

[TacOpsGuy320]

I have a 300 blackout Diamond Back and it runs great. Theres always the potential for things to get missed in the MFG process.

 

[Gabriel]

I have a 300 blackout Diamond Back and it runs great. Theres always the potential for things to get missed in the MFG process.

Yeah, if my job was sitting at a desk assembling bolt carrier groups ten hours a day, I can see getting it backwards every once in a while after your brain goes dead from repetition. That being said, there should be a function check and test fire later down the line before it goes out the door.

 

[TacOpsGuy320]

Yeah, if my job was sitting at a desk assembling bolt carrier groups ten hours a day, I can see getting it backwards every once in a while after your brain goes dead from repetition. That being said, there should be a function check and test fire later down the line before it goes out the door.

I completely agree. It’s not unheard of to want something that you purchase new to work as designed.