.223 fail to fire

[swampy]

I'm sorting through a bucket of once fired brass and I found a dozen unfired rounds. PRVI brand. Three show extremely light primer strikes. The rest look untouched. I compared the cases to once fired brass, new loaded ammo and a few FTF from my AR that also have extra light primer strikes. There doesn't appear to be anything different about these FTF cases. The 3 from my AR (fed 193) were tried several times but failed each time. I haven't tried the recently sorted ones.

My questions: The FTF doesn't appear to be a dud primer as the firing pin hit is barely noticable in any of them. With the cases measuring the same and appearing the same what causes the light or non existant primer strike? If this is a case problem then I don't want to run these bad cases through the reload process. I can't see any rim thickness issues, the rim, case length, overall cartidge length, angles and everything else seem normal and are identical to factory ammo and once fired cases compared side by side. They all fit in a case gage as they should.

As a curio bonus question. I found 2 rounds that appear to have a deep set plastic plug in the primer pocket and an orange/white plastic or nylon plug in where the bullet should be. I'm guessing this is some sort of dummy to simulate a FTF or snap cap type of thing. Anyone got any ideas if I'm right about what these are?

 

[Supermoto]

extremely light strikes on AR is from the floating firing pin. The hammer did not hit the firing pin

 

[swampy]

Is it common that the same case rechambered will continue to do the same thing? I have a few of these from my AR and neither of them will fire on a 2nd or 3rd try. The primer markings are unchanged after 3 tries. They look nearly untouched. That is what made me figure it is a case oddity. The ones I have from the bucket I'm sorting have even lighter strikes or no marks at all.

 

[Supermoto]

no. if they look near untouched then the firing pin is not hitting the primer. For some reason the bolt is out of battery or the pin is broken. Bad primers will have a dimple in them that is noticeable but not as deep as a fired one

post some pics if you can

 

[Jasper]

drop the loaded round in a case gauge.

excessive sizing (bumping headspace back too far) can also cause light strikes. not usually seen in factory ammo, but anything is possible

 

[EddieCoyle]

A couple of light strikes on the same round will pulverize the priming compound. Once this happens, you could hit the primer with an ice pick and drilling hammer and it won't go off.

A Boxer primer has the anvil at the top, with solid priming compound between it and the primer cup. Denting the cup will enough force will squeeze the solid compound above it into the anvil and it will go off.

Hitting it with not enough force to make it go off cracks the priming compound. Do it a couple of times and you gradually force the cup all the way to the anvil with nothing left to squeeze and go off.

I know this because I have an Uberti copy of the Colt Lightning pump action rifle. It has a weird two-piece firing pin that has a habit of - you guessed it - light striking. I carefully pulled apart some rounds that didn't go off after being hit a few times and that's what I saw: Powdered priming compound and the cup touching the anvil. I switched to Federal primers and the problem disappeared.

 

[DukeInFlorida]

I lube my firing pin with Militec-1 (synthetic) and it works slick in any weather, hot or cold.

And, the unanswered BONUS question is right... Those are dummy loads. A great game to play is mix a few of those in with your regular rounds in a mag, and do a "high stress clear the jam" exercise. You'll need the practice for when the zombies are breathing down your neck and your gun jams.

 

[swampy]

The few that came from my rifle were tried several times over and over. The AR fired the round before and after each with no problems. Still however, after several tries there was barely a scratch, let alone a dent, on the primers. It looks like the case isn't being held against the bolt face. When I disassemble the rounds I will try to preserve the primers to see if they are intact. I'll see about posting photos. I thought it was an anomoly to my gun until I started sorting 2 different loads of once fired brass and found similar rounds in the buckets. I did gage them in a dillon gage and all are fine.

 

[NavelOfficer]

Grab that magnifying glass...you aren't trying to chamber/shoot .222 Rem or some such, are you? .222 Rem are shorter than .223 at the shoulder/neck: .222 Rem Magnums are a bit longer. Just a wild shot that a few oddities may have gotten comingled with the bulk of the NNY/PPU cartridges.

 

[Admin]

extremely light strikes on AR is from the floating firing pin. The hammer did not hit the firing pin

+1

 

[TZCHRIS]

What causes the 'floating firing pin' ? Just had the same issue with 3 of 500 rounds, all are LC brass and loaded identically. Very light primer stike marks on all 3 cases? Do we know if this is the brass or the firing pin?

 

[EddieCoyle]

What causes the 'floating firing pin' ?

Nothing causes it. The rifle is designed that way. A floating firing pin is not a failure, it's a design feature.

 

[TZCHRIS]

is this common with all ammo and all AR's? I was using some new reloads, made me think I had bad primers or something? How or what causes this? Is it a rapid fire type thing? Is it safe to deprime these rounds? Sorry for all the questions, I take much pride in trying to make 'perfect' ammo, just want to be sure I'm not doing something wrong.

 

[drgrant]

You won't get true "light strikes" in an AR unless your gun or the ammo is ****ed up. (eg, broken parts, or primers not seated properly in ammo, etc. )

-Mike

 

[Fixxah]

I modified the hammer spring in one of my ARs to lighten the trigger pull and had light strikes on a few rounds. Tossed that spring ASAP. If one wants a light trigger buy a two stage. Not sure that your issue hasn't been covered, I am not an armorer anyway.

I assume it is your first time shooting the gun or you've never taken it apart to clean the crud out and lube it as would be necessary for proper function. It is simple to dismantle and you will have a much better understanding of how it functions.

 

[TZCHRIS]

Gun is spotless, M&P Sport with 30 rounds thru it up till yesterday. Does paying $600 for an AR have anything to do with it?

 

[bpm990d]

It's a design feature. Has nothing to do with the cost of the gun. Take it apart and look at it when the bolt is extended and when it is back in the carrier and you will understand.

B

 

[jasons]

I lube my firing pin with Militec-1 (synthetic) and it works slick in any weather, hot or cold.

Never lube the firing pin in an AR, it's designed to run dry. Lube will just mix with carbon and other crud and gum up the works.

 

[highscore]

Primers seated too deep?