Unusual Malfunction

mark46th · 06-27-2012, 16:39

My son is an LEO- While adjusting a new optic, his M4 started have a failure to cycle. He took it to his armorer who discovered a piece of primer in the gas tube. The armorer said he had never seen anything like it in 30 years. The armorer thought it was the Winchester ammo he was using...

longrange1947 · 06-27-2012, 19:35

Never saw that in the M4 but have in the SR25 shooting Winchester ammo.

**Team Sergeant** · 06-27-2012, 23:32

Quote:

Originally Posted by mark46th

My son is an LEO- While adjusting a new optic, his M4 started have a failure to cycle. He took it to his armorer who discovered a piece of primer in the gas tube. The armorer said he had never seen anything like it in 30 years. The armorer thought it was the Winchester ammo he was using...

The anvil?

Rob_Frey · 06-28-2012, 17:50

In the end of the gas tube that goes into the Gas Key?

Was he shooting 5.56 in a .223 chamber and popped the primer?

mark46th · 06-28-2012, 22:24

A piece of the primer, not the whole thing, ended up in the gas tube, I don't know how far, but the armorer saw it when he shined a light in to the tube. Next time I talk to him, I will get more details...

Gene Econ · 06-30-2012, 05:59

Quote:

Originally Posted by mark46th

My son is an LEO- While adjusting a new optic, his M4 started have a failure to cycle. He took it to his armorer who discovered a piece of primer in the gas tube. The armorer said he had never seen anything like it in 30 years. The armorer thought it was the Winchester ammo he was using...

Guys:

Happened to me with a JP upper and some handloads. Can't remember the brand of primer. The primer blew and got stuck in the gas key. Had to totally replace the gas key.

I can't begin to imagine the probability of that happening as the primer barely fits into that thing.

Gene

mark46th · 06-30-2012, 21:02

I spoke to my son. The piece of the primer was in the gas key, all the way to the back of it.

Tuukka · 07-07-2012, 06:05

I have seen primer parts only once in the gas key.

Just witnessed this week a primer wedged in between the bolt carrier and cam pin, was a bitch to remove the carrier from the weapon.

**Ambush Master** · 07-07-2012, 07:37

I heard about primers comming out and locking up M60s back in the Late 80s to early 90s. That put my "Reloading Operation" of .308 on hold.

Iraqgunz · 07-11-2012, 21:49

I have personally seen 5 documented cases of this happening. In every single it was due to the chamber being non 5.56 and the primer blew back into the weapon during the cycle of operation.

The weapons that I know that were involved were Bushmaster carbines and 1 DPMS.

**The Reaper** · 07-12-2012, 17:31

Loose primers are generally a pressure or overworked brass indicator.

The chamber issue can cause it as well, via pressure spikes.

Do not shoot 5.56x45 in .223 chambers.

TR

Gene Econ · 07-12-2012, 18:28

Quote:

Originally Posted by Iraqgunz

I have personally seen 5 documented cases of this happening. In every single it was due to the chamber being non 5.56 and the primer blew back into the weapon during the cycle of operation.

The weapons that I know that were involved were Bushmaster carbines and 1 DPMS.

Iraqgunz:

You have only seen five cases of blown primers in AR's? He, he, he. I have seen guys shoot rapid fire strings and blow several primers in one string. And it wasn't because they were shooting 5.56 through .223 chambers and jammed the bullets into the rifling, thus causing a pressure spike.

It was because they thought they were getting over by getting another twenty fps out of a already too hot load, fired on a more than average hot day, after their ammo sat in the sun for a few hours and cooked.

I don't take blown primers as easily as some guys. It means the guy either made a mistake in his handloading or took an unnecessary risk to win a match.

That said, I can't recall one experience with Lake City 5.56 blowing a primer in an issued service rifle or carbine. Crimped primers do work.

Gene

Iraqgunz · 07-12-2012, 19:19

No, I mean specifically 5 cases of primers that have blown back into the upper and getting into the carrier key. In all the cases that I examined the ammo was either M855 or M193. All the chambers that I checked were in fact not up to 5.56 specs.

Quote:

Originally Posted by Gene Econ

Iraqgunz:

You have only seen five cases of blown primers in AR's? He, he, he. I have seen guys shoot rapid fire strings and blow several primers in one string. And it wasn't because they were shooting 5.56 through .223 chambers and jammed the bullets into the rifling, thus causing a pressure spike.

It was because they thought they were getting over by getting another twenty fps out of a already too hot load, fired on a more than average hot day, after their ammo sat in the sun for a few hours and cooked.

I don't take blown primers as easily as some guys. It means the guy either made a mistake in his handloading or took an unnecessary risk to win a match.

That said, I can't recall one experience with Lake City 5.56 blowing a primer in an issued service rifle or carbine. Crimped primers do work.

Gene

Gene Econ · 07-13-2012, 06:14

Quote:

Originally Posted by Iraqgunz

No, I mean specifically 5 cases of primers that have blown back into the upper and getting into the carrier key. In all the cases that I examined the ammo was either M855 or M193. All the chambers that I checked were in fact not up to 5.56 specs.

OK -- now I am curious.

What process did you use to inspect the chambers and how are you sure the chamber was the problem and not the gas system / timing?

BryanK · 07-13-2012, 06:54

One of the gunsmiths in my neck of the woods had posted the following reply regarding this same issue. I have not used him as a 'smith before, but he gets some good reviews from the locals. Here was his reply on another forum "marylandshooters.com":

Quote:

Having Primer Pop out? Its likely your Throat or Feed Ramps are causing "Pressure Spikes" and popping Primers. This can be remedied by recutting the throat and recutting the Feed Ramps. Our Throat Recutting is listed as an additional Service. Primers Popping CAN also be caused by bad Feed Ramps or "Clickers" that push rounds into the casings when feeding. This increases Chamber Pressure as well.

...This Service primarily helps reliability with wide ranges of Ammunition and certain Projectiles (Soft Point, Ballistic Tip, Hollow Point). Often AR15's have Feed Ramps that are rough, or worse are "Clickers". A "Clicker" Ramp can be identified with a Ballpoint Pen. You run the Pen tip up the where the Upper Receiver Stops and the Barrel Extension Ramps Begin. If the Tip hangs up you have a "Clicker". This WILL result in Failure to Feed Malfunctions with certain Ammunition. A "Clicker" can also force a Projectile to be forced into the Casing which can increase Chamber Pressure dramatically, which is BAD.

This Service also keeps the Locking Lug Area and your entire Weapon from accumulating Brass Shavings which can affect reliability. Polishing the Feed Ramps minimizes rough areas that shave material as Ammunition pass over them. If enough Brass/Copper Shavings accumulate the Bolt will fail to rotate into battery and will result in malfunctions.

Alternate Benefits include reducing Brass Casing Damage. Reloaders tend to appreciate this added benefit. Effortless Feeding and Proper Ramp Geometry also minimizes Bullet Deflection when Feeding/Chambering Rounds. Projectile Deflection and Damage can affect the Weapons Accuracy/Consistency.