SFAR debris in fire pin chamber

[Skankyfrankie]

New to AR, Took the new SFAR out first time after a cursory cleaning. I did not take bolt apart (I know I know)
On shot 7 no primer contact tried once more same thing just a tiny barely visible scratch.
Pulled bolt, could see something brass or copper not round flush in the fire pin hole.
Pulled fire pin and found a small brass looking shaving. End of fire pin kind of marred up. It kind of looked like a piece of a primer. Way to big to go through pin hole. Wind got it before I devoted it so no pictures. The pin looked like impacted brass on the tip, I was able to clean it up.
Is there anything in the firing pin chamber that could come apart or is it likely mfg debris?
Is the firing pin suppose to be spring loaded because it is not?

It fired fine after but wondering is something inside broken?

 

[NikA]

Sounds like a pierced primer on a previous shot and resultant primer pieces in the FP channel.

 

[Skankyfrankie]

My thought as well but how did it get in there? And all my brass were in tact.

 

[noahmercy]

My thought as well but how did it get in there? And all my brass were in tact.

May have been from a proof load at the factory.

 

[Skankyfrankie]

So nothing normally in there except the pin, no guides or springs right?

 

[RoninPA]

Hate to say this but I will. What does it show in the parts breakdown in the manual? Some folks forget that the manual/parts breakdown can be a good place for information.

 

[Skankyfrankie]

It says ruger quality control should have caught a half primer in the fire pin pocket lol. It doesn’t show anything in there except the pin

 

[Mobuck]

"So nothing normally in there except the pin, no guides or springs right? (and later) It says ruger quality control should have caught a half primer in the fire pin pocket lol. "
In 'true' AR system, there's no springs or anything else inside the bolt other than the FP nor is there room for 'half a primer'. That 'firing pin chamber' is part of the working mechanism of the design. The gas from the gas tube enters this space forcing the bolt carrier to the rear which in turn unlocks the bolt from the barrel extension. It's possible a bit of machining debris could have been trapped in the gas tube/block and been blown into the bolt carrier by firing(probably a one time thing). Original design AR bolts have 3 tiny 'gas rings' in a groove about midway along the bolt's body. Assuming Ruger uses AR designed bolt, the tiny bit could also be a piece of a broken gas ring from the bolt which IS or could become an issue later.
Post a pic of your bolt and I can confirm.

 

[Skankyfrankie]

Good info it looked like part of the primer, wind got it before I saved it but I’m going to open it and inspect the gas rings. Still not clear how it could get where it was unless it was there during assembly. Too big to fit past rear of pin.

 

[Skankyfrankie]

And there is a fair amount of clearance around front of pin chamber. Also I did not say it was a primer I said part of a primer like part of the ring. It didn’t look like gas rings from pictures I see of those but I’m going to open it and look.

 

[Skankyfrankie]

Could it be something from the gas regulator? I’ll open and inspect it also. I did not know the gas goes into the firing pin chamber. I did say new to ar or did I lol… and it is firing normal now

 

[kmoore]

I always had a backup firing pin when shooting matches with an AR. They do have/get pierced primers and that can/does/might cause a nick/chip/broken firing pin. I still keep an extra firing pin in the parts bag for each AR I have. There so cheap and easy to change out, I also just do that while cleaning anyway if I believe I am up to a few thousand rounds.

 

[Mobuck]

My comments were based on a true AR designed system. I've never even seen a SFAR first hand but the disassembly video indicates this does have DI drive and gas rings on the bolt. With that settled, it takes about 15 seconds to determine if you have a broken gas ring. If you've already seen the firing pin(Pulled fire pin and found a small brass looking shaving.), you've seen the gas rings (true AR has 3 small rings or one with three spirals).
New gun, lack of lube, rough parts can all result in a gas ring snagging on the rear bore of the bolt carrier. They're not 'fragile' but can and do get tweeked or broken during installation and fail during initial firing.
Here's my thoughts and procedures when starting up a new AR platform: Don't be afraid to lubricate. My new assemblies smoke from all portals the first few shots. Unless you've just parachuted into the desert in the middle of a sandstorm with your new AR, there's no reason not to lube it till it drips. There are little holes in the side of the bolt carrier to vent gas during firing. You can slide the bolt forward until the gas rings show through those holes and give them a drop of oil w/o even taking the bolt out of the carrier. Oh speaking of this, there's no such term in AR nomenclature as 'firing pin chamber'.
I'd like to be more help but this probably just new gun startup glitch.

 

[Skankyfrankie]

Thanks I have not pulled bolt out but plan to do that soon and look at gas rings but it didn’t look like pictures I see of gas rings. It was lubed and once debris was removed it functions fine. Still I’ll look

 

[Skankyfrankie]

Here is another question while I have your attention. New stag arms 15. Fires with several different plastic mags including pmag gen2. But pmag gen3 doesn’t feed bolt pushes round up to feed ramp then rides over. Usually on 3rd round.
Tried several gen 3 including the pinned 30 rd that hold 10. Several new 30 rd and several new 10 rd.

 

[Skankyfrankie]

Here is another question while I have your attention. New stag arms 15. Fires with several different plastic mags including pmag gen2. But pmag gen3 doesn’t feed bolt pushes round up to feed ramp then rides over. Usually on 3rd round.
Tried several gen 3 including the pinned 30 rd that hold 10. Several new 30 and several new 10 rd.

 

[NikA]

I think there's a magazine stop different between Gen2 and Gen3, cannot recall exact specifics.

 

[Mobuck]

A 'bolt over base' failure to feed is often indicative of short stroking/under gassing. You didn't say how many rounds you loaded in the mag when this stoppage occurs. Full count or less? Some new mags just need some break-in time.
FWIW, I use P-Mags interchangeably w/o regard for series or capacity but seldom load to full count. (old time habit)

 

[daveag.]

CLP is your friend with an AR. Breakfree.

 

[Skankyfrankie]

It was lubed with break free. Gen 3 we’re new gen 2 we’re used. Will look closer Sunday. Thanks all

 

[Skankyfrankie]

For the sfar ruger is giving a new firing pin. So I’ll use new one keep this one as a spare

 

[Mobuck]

I don't wish to seem growly but if the BCG wasn't disassembled and various parts lubed with appropriate slickery stuff, it wasn't 'lubed'. I really am trying to sort out/solve your issues.
I assemble AR platform firearms to meet specific customer requests/needs so I get to handle lots of these. The primary issue I find is people believe all the stories brought back from 'the sandbox' by military users. Different environment, different use parameters, different logic vs the civilian recreational user.

 

[Skankyfrankie]

The stag arms BCG was lubed with Lucas gun lube and tiny bit of gun grease on bottom of BC. Mag pul says hand cycle full mag. If it works it’s not the mag. That’s easy to try. Relubing the BCG will happen after that and if it didn’t hand cycle the first time I’ll try it again. I get it more lube but I know it was lubed and it fires several brands of plastic mags just not the gen3.

 

[krw]

It was good advice to run any new AR wet. It can start a big good bad discussion but I prefer wet. I have a pile of AR’s and accy’s. I also exclusively use 10 an 20rd mags. I love the straight alum 20’s. Also in AR’s you get what you pay for. I have never been around Ruger SFAR so I don’t have an opinion on those. But any AR10 platform is a different beast vs milspec 15 platforms

 

[Skankyfrankie]

The ruger SFAR is running fine now that the brass debri is out from the firing pin. The Stag arms 5.56 is the one not feeding the pmag gen3. Same mags work in the Christensen arms 5five6 wylde. All three are new less than 100 rds. Each.

 

[Mobuck]

" The Stag arms 5.56 is the one not feeding the pmag gen3. "
Anytime I hear someone say this, I'm forced to ask: Can you describe the problem? The most frequent cause is gas related. Even though the gun cycles OK with this mag or that one doesn't mean it's functioning CORRECTLY with any of the mags. Correct function isn't really displayed while firing with ammo in the magazine. Recently, I had an AR that functioned fine with older well used magazines but failed to feed properly with new mags and only achieved bolt lock on empty mag with one old mag. The reason had nothing to do with the mags. The primary reason for the malfunctions turned out to be gas related--gas block mis-aligned due to an incorrectly located gas block dimple. This was fixed and the rifle now functions 100% with any/all magazines tried.

 

[Skankyfrankie]

Thanks. Hope not the issue. Will have time to look soon.