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M4 LE / 11707 - Bolt Carrier Failure!!!!


Miami_M4
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I purchased my M4 LE / 11707 on October 6th 2004 under the impression that the Benelli M4 LE / 11707 is the most reliable, heavily tested and respected tactical shotgun on the market. I was willing to pay the premium associated with owning a Benelli and did.

 

I am very disappointed with product I had purchased since it “broke” after less than 200 rounds!

 

Background History:

 

October 6th 2004 – Purchased New in Box at an Authorized Dealer

 

October 7th 2004 – Lubed and Assembled for Shooting

 

October 9th 2004 – Went to the Range and fired:

(75) Rounds Winchester SuperX Game Loads, 12GA, 2 ¾, 3 ¼ DR EQ, 1 OZ, #7½ Lead Shot

(25) Rounds Remington Game Load, 12GA, 2 ¾ , 3 ¼ DR EQ, 1 OZ, #6 Shot

(10) Rounds Remington Slugger High Velocity, 12GA, 2 ¾ , 1800 FPS, 7/8 OZ Slug

Note* Fired all rounds with out any malfunctions

 

October 26th 2004 – Tactical Shotgun Class

 

Was able to fire the following prior to failure:

(10) Rounds Remington Slugger High Velocity, 12GA, 2 ¾ , 1800 FPS, 7/8 OZ Slug

(15) Rounds Winchester SuperX Game Loads, 12GA, 2 ¾, 3 ¼ DR EQ, 1 OZ, #7½ Lead Shot

 

Note* I fired the (10) rounds of Slugs in the first half of the class for sighting in purposes with out any malfunctions. I then began to fire the Winchester SuperX Game Loads in various drills we were doing when after (12) rounds the bolt began to “lock” back after each shot. I would try to use the bolt release, but that would not release the bolt. I had to actually “push” the bolt forward to close it. I did this (3) times, at which point I felt that it was unsafe to continue the class.

 

October 26th 2004 – Field Stripped and inspected why the shotgun malfunctioned.

 

I found that the Gas Piston on the left side of the barrel had impacted the Bolt Carrier with enough force to cause an indentation in the Bolt Carriers metal rail. This indentation then caused the rail on the bolt carrier to swell enough to prevent smooth operation in the receivers’ rail grooves. After further inspection, the right side rail has some indentation, with a slight deformation of the metal.

 

Summary:

 

I was not and do not use reloads in any of my shotguns!

 

“Standard, Off the Self” Remington Slugs and Winchester Bird Shot do not contain any “super powerful” charges that would cause this type of damage. It appears that the metal on the rails of this bolt carrier is “too soft”!

 

I am very disappointed with quality of the product I paid “good money” for. It is also embarrassing for you as well when your newest product “breaks” in front of a class of 24 law enforcement professionals who were all in awe of the Benelli M4.

 

The comments after the class, were “I will stick with my 870!”

 

Not good!

 

I am in the process of dealing with customer service, so I will keep you all posted.

 

I have detailed pictures of the bolt carrier and would like to post them but could not figure it out. So, let me know how to post images or I can post the PDF of the document I prepared for Benelli Warranty Service that includes detailed pictures and explanations.

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Yours got further then mine did. I only got thru 50 rounds before it took a dump on me and the gas piston broke in half.

Good luck with customer service. It took them a month to simply mail me a replacement gas piston.

Your right about it being embarassing. Expecially after the kind of money we've laid out for a shotgun that is supposed to be uber reliable.

-Steve

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I'm getting the impression that the pistons:

 

a) are designed w/ insufficient diameter/thickness to prevent breakage or bending, or

 

b) are being fabricated in some substandard manner (possibly an outsourcing-related issue?), such that their metallurgical properties are inadequate to handle the loads that they are subjected to.

 

This is the 2nd piston-related failure I've heard of, both occurring w/ in the last 2 months. Not good. I hope the factory's USA branch is taking note of these issues & addressing them. No worse form of advertising than to have potential customers see your flagship product bite the dust.

 

Miami, I hope this is strictly a manufacturing issue instead of a design flaw. This thing supposedly passed some intensive testing to claim its title. If I were a Benelli USA rep., I'd be less than happy about my product breaking "...in front of a class of 24 law enforcement professionals".

 

Someone better get on the phone to Italy.

 

[ 10-28-2004, 10:17 PM: Message edited by: Double_wield ]

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OK, this is not a piston-related problem, but rather, it's the carrier this time. Once again, metallurgy seems to be the problem. I sincerely hope this gets resolved soon. I've got mine on order, but at the rate it's going, Benelli may have the fix instituted by the time they're finally made & delivered.

 

[ 10-28-2004, 10:28 PM: Message edited by: Double_wield ]

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I've been thinking about this problem while at work today. There may be something wrong with the ARGO system.

Tap an unloaded Benelli M4 with the bolt closed on the deck on the butt stock, you will see the bolt retract. The action is very smooth and requires very little to cycle the weapon.

The ARGO system was ment to bleed the proper amount of energy (gas) to reliably cycle the weapon reguardless of the power or size of the load. This adds up to make the weapon reliable at cycling low recoil rounds.

Have you inspected the area where the piston stop is on the barrel? This over travel stop keeps the piston from entering the receiver too far. Any undue wear in this area? The ARGO system could be dumping way too much gas into the piston and causing undue stress on the system. Just a theory.

Any damage to the pistons themselves that you can see?

Those of you whom have the Benelli M4 with higher round counts, is your carrier face wearing like Miami_M4's is?

The left hand piston is the one in which shattered on my rifle. I really hope these issues are flukes and not a design flaw.

I would suggest sending them the entire shotgun to inspect the ARGO system. Or you can take your chances with a replacement carrier and see if that solves your problems. I took that route since shipping overnight from AZ to MD is VERY expensive. I'd ask them to replace the pistons as well, since they have now been impacting on an uneven surface.

If you have other pictures you'd like to post, I'd gladly host them for you if you want. Just e-mail them to me.

-Steve

 

[ 10-29-2004, 04:38 AM: Message edited by: stevenb ]

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To answer your questions regarding the rest of the ARGO System on my M4:

 

Gas Pistons: They look fine, and travel smoothly in their tubes.

 

Gas Piston Stops in the Reciever: No damage or signs of overtravel impacts

 

Reciever Rails: Again no damage or signs of "excessive" wear.

 

That is why I think the issue is related to the manufacture of the bolt carrier.

 

I sent the whole gun back, at thier request.

 

They felt that due to product liability issues, a simple replacement of the bolt carrier would be risky.

 

That indicates to me that there may be "other" issues with the M4s that we do not know about, and they want to see if this one has any of the "other" issues.

 

I requested a complete replacement, just for "peace of mind", since this too is not a range weapon, but my home defense weapon.

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