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M4 11707 Bolt Carrier Failure w/ PICS


Miami_M4

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Well, it happened to me again!

 

My M4 11707 LE broke over the weekend and this time it is in a different spot.

 

I have less than 350 rounds thru it since I got it back after Benelli replaced the bolt carrier and barrel when it broke the first time.

 

During a routine cleaning and inspection after the shoot, I noticed that the bolt carrier had cracked. The crack is on the left side of the bolt carrier and is just below the bolt head pin cam channel.

 

See Photos:

 

Benelli M4 Cracked Bolt Carrier Pictures

 

I use Remington Game Load #6 2 ¾ inch shells exclusively for the 3-Gun matches I shoot in, and occasionally Remington Slugger Slugs for paper targets in certain stages. It is equipped with the 4-Port “Low Recoil Rounds” barrel that has been the subject of recent threads on this board.

 

After reading a thread “M4 Barrel Markings” posted by STA on 6-11-2005, and analysis by STA and others, I am beginning to believe that you CANNOT shoot “standard load” 2 ¾ shells or 3” shells in a M4 equipped with a 4-Port “Low Recoil Round” barrel.

 

If you do, it will cause “battering” of the gas pistons, and bolt carrier, which in turn will lead to failure.

 

But, if you read the “M4 SUPER 90” Manual (G0093602 – 01/2003) it states on page 72, “Choice of Ammunition” - “The M4 can use 12ga. Shells with 70mm (2” ¾) or 76mm (3”) cases.”

 

So, now what do we do?

 

I certainly do not want to be limited to “low recoil” rounds in my super duper, hardcore, military approved M4!

 

And, for those of you who will say; “if it breaks Benelli will buy me a new one”, what do we tell the family members of the person who was relying on an M4 as a home defense gun, and it broke during an incident that cost them their lives?

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I am sure that the gun civilians purchase and what the military gets is 2 diff guns. The military proving grounds puts test guns through all kinds of he!!.

If they happen to be the same, know doubt with reports from the field will change the status of M4 being issued. Well then again our liberal media may not report it until the war is over so our soldiers will be @ risk. Good luck with that getting fixed. They may tell you it is shooter error!LOL

IF i was you and it gets fixed you better sell it on gunbroker.

brice

Originally posted by Miami_M4:

Well, it happened to me again!

 

My M4 11707 LE broke over the weekend and this time it is in a different spot.

 

I have less than 350 rounds thru it since I got it back after Benelli replaced the bolt carrier and barrel when it broke the first time.

 

During a routine cleaning and inspection after the shoot, I noticed that the bolt carrier had cracked. The crack is on the left side of the bolt carrier and is just below the bolt head pin cam channel.

 

See Photos:

 

Benelli M4 Cracked Bolt Carrier Pictures

 

I use Remington Game Load #6 2 ¾ inch shells exclusively for the 3-Gun matches I shoot in, and occasionally Remington Slugger Slugs for paper targets in certain stages. It is equipped with the 4-Port “Low Recoil Rounds” barrel that has been the subject of recent threads on this board.

 

After reading a thread “M4 Barrel Markings” posted by STA on 6-11-2005, and analysis by STA and others, I am beginning to believe that you CANNOT shoot “standard load” 2 ¾ shells or 3” shells in a M4 equipped with a 4-Port “Low Recoil Round” barrel.

 

If you do, it will cause “battering” of the gas pistons, and bolt carrier, which in turn will lead to failure.

 

But, if you read the “M4 SUPER 90” Manual (G0093602 – 01/2003) it states on page 72, “Choice of Ammunition” - “The M4 can use 12ga. Shells with 70mm (2” ¾) or 76mm (3”) cases.”

 

So, now what do we do?

 

I certainly do not want to be limited to “low recoil” rounds in my super duper, hardcore, military approved M4!

 

And, for those of you who will say; “if it breaks Benelli will buy me a new one”, what do we tell the family members of the person who was relying on an M4 as a home defense gun, and it broke during an incident that cost them their lives?

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I know little about the M4, but the 2005 catalog does state the gun is designed for 'light tactical loads', whatever the heck that means:

 

m4.jpg

 

The current website catalog page does not appear to mention the 'light tactical loads':

 

http://www.benelliusa.com/firearms/m4.tpl

 

and Miami is saying his owners manual does not either :confused:

 

I'm confused too.

 

I'd like to know so I can give out correct info.

 

mudhen - CA

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Hey Miami, first let me say BIG drag, on your bolt carrier....

Is a NON low recoil round barrel available for your m4?

 

Reason I ask is because a "low recoil round" barrel is typically designed for just that and only that, low recoil Police, and Military rounds ( they have their own designation) for close quarter combat, and training.

In fact many agencies are only authorized to use low recoil ammo, in buck or slug.

 

I am assuming that the standard barrel is a two port which the ARGO system can regulate between standard, and magnum rounds effectively, but it is quite possible that it can't regulate the gas pressure of 4 ports fast enough from a standard pressure load and racking the action way to hard. ( remember the idea of 4 ports is to grab more pressure to cycle the action from a low recoil round.)

 

If thats they case then yes benelli should put that in their manual...

 

That crack looks pretty freaking bad, it took a serious whop to shift the metal structure sideways like that..

Or it wasn't properly relieved of forging tension and just cracked from harmonics.. Either way hope you get it squared away....

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Terrible news about your carrier, but a big thanks for providing photos.

 

Back when I was tracking down the low recoil barrel, customer service confirmed two port barrels were not available anymore, but assured that I could use any 2-3/4" or 3" shells in the 4 port barrel (#81246). I always had some question in my mind that a system which was designed for rugid military use with two ports, could now handle any loading with those two extra ports added. I really interpreted that barrel marking to mean "low recoil only", which is what prompted me to call Benelli a few months back.

 

I can't recall if they had the verbage about the modified gas system on their website, but I also have two of their print catalogs showing this statement. As for the website, I see they've made some very recent changes. Due to the possible legal issues of the mag extensions, the extension info and pic are now missing from the M4 page. They've gone so far as to remove all info/pics on the entire line of mag extensions from their accessory page as well. A quick browse using Google's cache function or web.achive.org will return views of the old web pages in all their extension toting glory.

 

Good luck in repairing your M4 and please let us know what you hear back from Benelli.

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Thanks for all the feedback, and I am beginning to see what I am going to have to do.

 

For all of us that have 4-Port "Low Recoil Rounds" Barrels on our M4's, we are going to be limited to just that, Low Recoil Rounds.

 

I am just starting to work with Customer Service, since they are short staffed this week. I will keep you posted on what I find out.

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Miami, one further question ..

 

After disassembling and finding the carrier cracked, did you happen to remove the gas plug assemblies from the barrel for inspection? I'm just curious if you made sure that each gas plug cap (# 273J in the parts manual) was free to push in against the spring.

 

I would think that if either of these become stuck or even sluggish, it would prevent the excess gas from being relieved, causing much higher pressure to be exerted on the pistons and carrier. Just a thought ?

 

SA

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STA - The gas pistons as well as the rest of the gun is fine.

 

Look, the situation is as we have all come to see, 4-Port "Low Recoil Rounds" barrels are for that type of ammo ONLY, no matter what Benelli says or states in thier manual.

 

It's just a shame that we have to do this type of research ourselves!

 

I would love to get a 2-Port barrel for my M4 11707, but we will have to see what Benelli Customer Service does with my repair. And after reading some other threads, I do not think that is going to happen.

 

Maybe a letter from an Attorney might help...hmmm

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  • 3 weeks later...

How many have had this problem? Comon or not?

 

I just droped 1200 bucks on the new and improved "Combat proven", "Marine tough", shotgun. and find this out. I hope this is not comon?

 

So much for confidence in my new battle proven shotgun.

 

Attorney's live for this kind of stuff. I hate most lawyers and would only use one as a last alternative. Hope someone from Benelli will give us some insight on how comon the problem is and if it is a problem how they plan on makeing it right.

 

Not real happy right now.

 

Byron

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