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Benelli M4 Feeding Problems

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I have the following Feeding Problems with my Benelli M4:

The new round is on the Carrier/Shell Lifter, the Bolt is in the rearward position but the Carrier doesnt come up. I have to rack the bolt or tip against the Carrier/Shell lifter. Then it goes up and feeds normaly. How to cure this Problem?

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Maybe you're not explaining it right; or I'm just not getting it ... The carrier comes up when the bolt begins moving forward, not when it is in the rearward position. Are you saying that it doesn't come up when the bolt begins to move forward, and that you have to rack the bolt back a second time to get it to raise?

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I have the following Feeding Problems with my Benelli M4:

The new round is on the Carrier/Shell Lifter, the Bolt is in the rearward position but the Carrier doesnt come up. I have to rack the bolt or tip against the Carrier/Shell lifter. Then it goes up and feeds normaly. How to cure this Problem?

 

I am confused by your problem, you are either not explaining it well or you are not familiar with how an m4 works.

 

Try this at the range ...

 

1) - Lock the bolt back. Bolt release button is out, cartridge drop lever is in. The shell lifter is locked down.

2) - Put a round in the chamber and press the bolt release. The bolt comes forward, the cartridge drop lever pops out, and the shell lifter is now unlocked and you can load rounds into the tube as you desire.

3) - When you fire, the chambered round is ejected, the bolt carrier moves back and resets the trigger, a round gets ejected from the tube onto the lifter, the bolt comes back forward, triggers the lifter, grabs the next shell and chambers it

4) - Rinse and repeat.

 

Where in that procedure do you have a problem?

 

I reread your problem ... are you merely stating that when the bolt is locked back, that the shell carrier won't pop up? It's not supposed to ... it pops up when the bolt is released, and only when the bolt is released.

 

I would suggest reading the manual and familiarizing yourself with the m4 operation, it is quite a bit different from other designs that you may be used to.

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I have the following Feeding Problems with my Benelli M4:

The new round is on the Carrier/Shell Lifter, the Bolt is in the rearward position but the Carrier doesnt come up. I have to rack the bolt or tip against the Carrier/Shell lifter. Then it goes up and feeds normaly. How to cure this Problem?

 

Let me guess, this is not a cycling issue, but rather an issue with you trying to baby the BCG closed?

 

-OR-

 

You got a weak mag spring that is not allowing the shell to be fully fed onto the top of the shell lifter in time.

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I am confused by your problem, you are either not explaining it well or you are not familiar with how an m4 works.

 

Try this at the range ...

 

1) - Lock the bolt back. Bolt release button is out, cartridge drop lever is in. The shell lifter is locked down.

2) - Put a round in the chamber and press the bolt release. The bolt comes forward, the cartridge drop lever pops out, and the shell lifter is now unlocked and you can load rounds into the tube as you desire.

3) - When you fire, the chambered round is ejected, the bolt carrier moves back and resets the trigger, a round gets ejected from the tube onto the lifter, the bolt comes back forward, triggers the lifter, grabs the next shell and chambers it

4) - Rinse and repeat.

 

Where in that procedure do you have a problem?

 

I reread your problem ... are you merely stating that when the bolt is locked back...

 

No, Bolt is not locked back. It occurs during the cycling Sequence:

 

3) - When you fire, the chambered round is ejected, the bolt carrier moves back and resets the trigger

, a round gets ejected from the tube onto the lifter...

 

-> Bolt is not going forward but is stuck in the rearward postition, Round is on the Carrier, but Carrier does not come up. Have to give it or the bolt a tip.

 

... the bolt comes back forward, triggers the lifter, grabs the next shell and chambers it

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No, Bolt is not locked back. It occurs during the cycling Sequence:

 

3) - When you fire, the chambered round is ejected, the bolt carrier moves back and resets the trigger

, a round gets ejected from the tube onto the lifter...

 

-> Bolt is not going forward but is stuck in the rearward postition, Round is on the Carrier, but Carrier does not come up. Have to give it or the bolt a tip.

 

... the bolt comes back forward, triggers the lifter, grabs the next shell and chambers it

 

What ammunition is being used? Is the M4 in stock configuration or modified?

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Do you have a low recoil barrell? I would check the BCG to see if any of the metal has been splayed or deformed.

 

Wow, this looks like it is going to be a good post!

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No, Bolt is not locked back. It occurs during the cycling Sequence:

 

3) - When you fire, the chambered round is ejected, the bolt carrier moves back and resets the trigger

, a round gets ejected from the tube onto the lifter...

 

-> Bolt is not going forward but is stuck in the rearward postition, Round is on the Carrier, but Carrier does not come up. Have to give it or the bolt a tip.

 

... the bolt comes back forward, triggers the lifter, grabs the next shell and chambers it

 

Wait, is this during firing or during hand cycling?

 

M4's have a "shelf" that you can set the bolt carrier on, if you slowly cycle it you can set the carrier on the shelf, which I believe is actually the lifter engagement point. It needs some inertia to get past this point ... so if you are slowly hand cycling it, that is your "problem", or lack of one in this case.

 

If this is occurring while actually firing, then you have a problem.

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Wait, is this during firing or during hand cycling?

 

M4's have a "shelf" that you can set the bolt carrier on, if you slowly cycle it you can set the carrier on the shelf, which I believe is actually the lifter engagement point. It needs some inertia to get past this point ... so if you are slowly hand cycling it, that is your "problem", or lack of one in this case.

 

If this is occurring while actually firing, then you have a problem.

 

 

I think he means it happens during shooting.

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My 11703 did the same thing after about 10,000 rounds. The cause was the bolt carrier had been deformed by the gas pistons. You could see the face of the carrier had been impinged. As the carrier would cycle to the rear, it would get stuck.

This is easy to check. Simply inspect the face of the carrier. Look at the edges of the guide rails on the carrier itself to see how the finish is wearing. Cycle the weapon by hand to feel for any resistance towards the rear.

 

If this is the problem, a trip to Benelli is in order. Mine went last year and they replaced the entire BCG, barrel, piston assembly and handguards with the newest model.

It took about a month though.

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My 11703 did the same thing after about 10,000 rounds. The cause was the bolt carrier had been deformed by the gas pistons. You could see the face of the carrier had been impinged. As the carrier would cycle to the rear, it would get stuck.

This is easy to check. Simply inspect the face of the carrier. Look at the edges of the guide rails on the carrier itself to see how the finish is wearing. Cycle the weapon by hand to feel for any resistance towards the rear.

 

If this is the problem, a trip to Benelli is in order. Mine went last year and they replaced the entire BCG, barrel, piston assembly and handguards with the newest model.

It took about a month though.

 

 

11703=4 port...right?

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Yes. It was a 4 port until it went back to Benelli. They replaced it with a 2 port model.

 

Very shocked you got 10K out of it before it went kaput.

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You don't happen to have any pictures of your old bolt carrier or receiver ... do you?

 

The old ones that were badly beat up ... I have 11.5k through my m4, and granted mine is the 2 port model, but I'd be interested in comparing my wear to yours.

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I'll look in my files when I have a chance.

The last few thousand rounds I had an increased amount of failures as the face of the bolt carrier deformed. The deformation could be seen on the sides of the rail due to the rubbing taking place on the inside of the receiver.

 

Most of the 10k was the Walmart cheapie loads. So they weren't tearing it up too badly. Within the first 50 rounds, I snapped one of the gas pistons. It functioned until the broken piston got jammed in the action.

That took Benelli about 45 days to send a replacement after I mailed them the broken one.

 

I tried to get Benelli to replace the entire receiver due to the wear along the carrier rail, but they declined.

 

I've had the Shotgun since 2004, so it's worked over pretty well.

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I am having similar problems with my new M4 #11707 with only about 200 rounds through it. It's a two-port barrel version, purchased April 2009.

 

I noticed while shooting my first few boxes of ammo that certain brands would "hang up" and the bolt would be stuck back, with the shell on the carrier, and needed some "forward assist" to get back into the chambered and breech-locked position. I chalked it up to "low power load cycling problems" that people seem to think will happen.

 

Well, as I did more shooting, I noticed this consistency in whether different brands would hang up or not. The loads were all over the place w.r.t. "light" vs. "heavy"... slugs, buck, birdshot, I did it all. The amount of kick didn't seem to matter as much as which mfgr. it was. Estate and Federal, no go; Remington and Winchester, much happiness.

 

This morning, while cleaning the gun after yesterday's outing, I did a final function check using some snap caps and some Fiocci dummy rounds. The snap caps cycled through perfectly (you know, those precision-machined aluminum jobbies). The Fiocci's would hang up, just like I described.

 

Reading what Unobtainium and StrangerDanger are saying about a "shelf"... I truly believe this shelf has some kind of ammunition-dependent sensitivity, and this creates problems even when all the parts are being slam-banged in live fire mode.

 

I have not had a safe opportunity to try hand-cycling my various brands of live ammo, but will do so at first opportunity.

 

Has anyone else encountered this problem with their M4 recently? This is really disappointing from a gun that retails for $1649. I thought I was getting the best.:mad:

 

Another thing that's kind of a let down is the fact that the ARGO gas system is really nothing more than a Benelli Inertia Driven system with a little gas assist to help kick the bolt carrier backwards. The length of the gas piston stroke is not sufficient to unlock the breech, and based on where the gas ports are located, that's probably a good thing, since the pressure would probably be much to high at that point in the firing cycle. The Inertial release of the bolt is still necessary to move the cycle along.

 

Makes me wonder why the ARGO components are needed at all if the Inertia Driven system is so great?

:(

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Jogusto,

Check your carrier for wear and deformation as I described. You should not have such trouble feeding any rounds.

When mine was at the end of the road, the carrier would get stuck when I would retract the bolt. I'd have to hit the charging handle to get the bolt handle to move forward.

 

One thing I do not like on the M4 is how easy it is to unlock the bolt from the barrel. Tap the butt stock on the ground and the inertia will open the bolt. Hit it hard enough and I would bet it would eject a round.

 

It's only locked in when the pressure to move rearward is coming from the bolt itself.

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I am having similar problems with my new M4 #11707 with only about 200 rounds through it. It's a two-port barrel version, purchased April 2009.

 

I noticed while shooting my first few boxes of ammo that certain brands would "hang up" and the bolt would be stuck back, with the shell on the carrier, and needed some "forward assist" to get back into the chambered and breech-locked position. I chalked it up to "low power load cycling problems" that people seem to think will happen.

 

Well, as I did more shooting, I noticed this consistency in whether different brands would hang up or not. The loads were all over the place w.r.t. "light" vs. "heavy"... slugs, buck, birdshot, I did it all. The amount of kick didn't seem to matter as much as which mfgr. it was. Estate and Federal, no go; Remington and Winchester, much happiness.

 

This morning, while cleaning the gun after yesterday's outing, I did a final function check using some snap caps and some Fiocci dummy rounds. The snap caps cycled through perfectly (you know, those precision-machined aluminum jobbies). The Fiocci's would hang up, just like I described.

 

Reading what Unobtainium and StrangerDanger are saying about a "shelf"... I truly believe this shelf has some kind of ammunition-dependent sensitivity, and this creates problems even when all the parts are being slam-banged in live fire mode.

 

I have not had a safe opportunity to try hand-cycling my various brands of live ammo, but will do so at first opportunity.

 

Has anyone else encountered this problem with their M4 recently? This is really disappointing from a gun that retails for $1649. I thought I was getting the best.:mad:

 

Another thing that's kind of a let down is the fact that the ARGO gas system is really nothing more than a Benelli Inertia Driven system with a little gas assist to help kick the bolt carrier backwards. The length of the gas piston stroke is not sufficient to unlock the breech, and based on where the gas ports are located, that's probably a good thing, since the pressure would probably be much to high at that point in the firing cycle. The Inertial release of the bolt is still necessary to move the cycle along.

 

Makes me wonder why the ARGO components are needed at all if the Inertia Driven system is so great?

:(

 

How many rounds total are through your gun? Some m4s (mine included) jam like crazy the first 100-200 rounds, and then are flawless for the remainder of their life. I don't know why.

 

The "shelf" has nothing to do with what ammo is being used, the shelf is actually the lifter engagement tab thing ... it requires that the bolt carrier have a bit of inertia to have the power to ride over and trip the lifter engagement tab ... if you hand cycle slowly, you can set the bolt carrier on the lifter engagement tab and it will stay there until you jar the weapon, and then the bolt carrier will fall.

 

The ARGO gas system was designed, as stated by benelli, to assure that the gun functions flawlessly when heavy night vision optics or other accessories are added to the gun. It's actually quite a beautiful system, extremely simple and reliable ... but yes, it is basically an upgraded inertia system, which is all it should be. The one weak point of the inertia system has been addressed by adding the dual gas pistons of the ARGO system.

 

If you have a low round count, I would suggest shooting some more before making any determinations about your m4. Also, as stated, you cannot baby it when cycling ... if you try to slowly, gently cycle the action, it will hang up on 3 different points potentially ... slam it like it was meant to be slammed, I promise you, you will not hurt the m4.

Edited by Duggan

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Check your carrier for wear and deformation as I described.

 

Thanks, SD, will do. I would think that having this kind of problem after 200 rounds indicates a defective unit from the manufacturer or "infant mortality" of the involved parts.

 

Anyone else having this kind of problem so soon after purchase?

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The "shelf" has nothing to do with what ammo is being used, the shelf is actually the lifter engagement tab thing ... it requires that the bolt carrier have a bit of inertia to have the power to ride over and trip the lifter engagement tab ... if you hand cycle slowly, you can set the bolt carrier on the lifter engagement tab and it will stay there until you jar the weapon, and then the bolt carrier will fall.

 

Hmm... this may be true with your weapon, but I can very repeatably pull the bolt all the way back, then release it (NOT slowly, but suddenly), and get a hangup *every time* with certain of my Fiocchi rounds, and *never* get a hangup with the aluminum snap-caps. This would tend to argue against the theory that the ammo has nothing to do with it. Field shooting results also argue that the ammo does matter.

 

I appreciate that body motion after the recoil might help matters a bit, but the bolt still needs to stop and change direction even when firing. Releasing abruptly from a fully drawn-back position is much different? Hmmm... not sure. You could be on to something, but then it means inertial voodoo is required for completely reliable operation, including a shooter who not only jerks back (required for the Benelli inertial system to work), but also springs forward again to help the bolt overcome the "shelf".

 

Rather that debate whether the issue is a problem or a non-problem, I'd like to understand how many others out there have experienced this problem, especially in a relatively new M4. Certainly, the OP seems to be one. SD seems to be another, albeit after a larger number of rounds through. Any others?

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I am having similar problems with my new M4 #11707 with only about 200 rounds through it. It's a two-port barrel version, purchased April 2009.

 

I noticed while shooting my first few boxes of ammo that certain brands would "hang up" and the bolt would be stuck back, with the shell on the carrier, and needed some "forward assist" to get back into the chambered and breech-locked position. I chalked it up to "low power load cycling problems" that people seem to think will happen.

 

Well, as I did more shooting, I noticed this consistency in whether different brands would hang up or not. The loads were all over the place w.r.t. "light" vs. "heavy"... slugs, buck, birdshot, I did it all. The amount of kick didn't seem to matter as much as which mfgr. it was. Estate and Federal, no go; Remington and Winchester, much happiness.

 

This morning, while cleaning the gun after yesterday's outing, I did a final function check using some snap caps and some Fiocci dummy rounds. The snap caps cycled through perfectly (you know, those precision-machined aluminum jobbies). The Fiocci's would hang up, just like I described.

 

Reading what Unobtainium and StrangerDanger are saying about a "shelf"... I truly believe this shelf has some kind of ammunition-dependent sensitivity, and this creates problems even when all the parts are being slam-banged in live fire mode.

 

I have not had a safe opportunity to try hand-cycling my various brands of live ammo, but will do so at first opportunity.

 

Has anyone else encountered this problem with their M4 recently? This is really disappointing from a gun that retails for $1649. I thought I was getting the best.:mad:

 

Another thing that's kind of a let down is the fact that the ARGO gas system is really nothing more than a Benelli Inertia Driven system with a little gas assist to help kick the bolt carrier backwards. The length of the gas piston stroke is not sufficient to unlock the breech, and based on where the gas ports are located, that's probably a good thing, since the pressure would probably be much to high at that point in the firing cycle. The Inertial release of the bolt is still necessary to move the cycle along.

 

Makes me wonder why the ARGO components are needed at all if the Inertia Driven system is so great?

:(

 

 

You are not familiar with the ID system based on the information you have provided. For clarification, look up a diagram of an ID system and then take your M4's BCG apart. There is no ID system. Remove the pistons and you got nothin'. They don't "assist". They do it all.

 

I only experienced this problem using HEAVY loads with a stock mag spring and extended tube.

 

However, the OP MAY experience this if his stance is crap (not leaning aggressively foreward) and his hold is weak.

 

I don't know the OP, their build, or stance, so I can only hypothesize, if I were to guess, I would assume that the OP is less than 150#, a smaller person, and does not hold a shotgun aggressively.

 

If my assumption is wrong, then I would move foreward to say that maybe you should mic the shells you are using and see if the diameter, etc. is out of spec.

 

Failing that, I would call Benelli USA, describe the problem, and see what they have to say before you fly off the handle.

Edited by Unobtanium

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So, I took off the stock rail and put on a Mesa side saddle with their rail.

 

Though I has stubs and looks the same, is it indeed a better rail?

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So, I took off the stock rail and put on a Mesa side saddle with their rail.

 

Though I has stubs and looks the same, is it indeed a better rail?

 

 

I think Mesa is crap, personally.

 

Anyways, back on topic...

 

How are you lubing the weapon? You need to lube the trigger group, you need to lube the tracks the BCG slides on, you need to lube the BCG itself, you need to lube the recoil-tube.

 

You do NOT lube the mag-tube or the pistons.

 

I lubed mine heavily with LaRue MG when I got it and proceeded to shoot Remington STS light target loads 5+1+1 rapid-fire with narry an issue the first trip out. Others, who fear the lube, seem to have issues.

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To be clear, my M4 11703 broke within the first 50 rounds. The left piston broke. It operated until the dislodged piece of the piston got jammed in the action.

It continued to operate sluggishly with one piston.

 

The piston broke because it wasn't heat treated properly, and I was feeding it 3" magnum Wolf buckshot on a 4 port barrel.

 

After that repair, the Benelli worked for around 10k rounds. Near the end, the action was doing what you describe. Hanging up at the rear and sluggish performance. The carrier was binding in the receiver.

 

So the entire weapon was sent back to Benelli. Several months later, it came back with a 2 port barrel, new carrier, new handguards, new piston system, choke.

 

The only thing that was the same was the receiver, trigger group and the stock. I had asked that the receiver be replaced also due to the extensive wear present on the inside rails, but they declined. After the Benelli is setup the way I want, I intend to have it refinished. Ion bonding for the steel and titanium parts, and type 3 anodizing with teflon for the aluminum parts.

 

As for the question about the Mesa rail. It's probably no worse than the factory rail. However, the mounting is suspect. You're putting a lot of weight on those 5 receiver holes. These screws are threaded into an aluminum receiver. You're also introducing a design that allows you to apply a lot of leverage on the shell carrier. Your chances of stripping the screws out of the receiver are higher as you install the bigger capacity shell carriers.

 

If they redesigned it with a solid true spec picatinny rail, and gave you a bracket that replaced the hanguard retention clips at the receiver, the strength would be greatly improved. This would require that you remove the magazine extension to install it, but it would be worth it.

 

Saying all this, I think the Sidearmor unit is a better design because it has the barrel mounted clamp that acts as a support so your receiver isn't taking the full load. Plus you're limited to 4 shells.

 

The Sidearmor unit is in need of improvement also though. That topic is ongoing in another thread.

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So, I took off the stock rail and put on a Mesa side saddle with their rail.

 

Though I has stubs and looks the same, is it indeed a better rail?

 

 

OOPS! Wrong thread. I wanted to post this on the bad receiver thread.

 

 

Mesa has been great to me. Very high quality and unique products.

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