More Benelli M4 Reliability Issues

[stevenb]

I've read about several people having the issue where the bolt is sticking to the rear during cycling. I'm currently running into this same problem. However it has been an ongoing problem and I've had probably 5000 rounds thru the weapon. You can make it stick to the rear simply by pulling the bolt to the rear (not the bolt lock)

Under close examination of the bolt carrier, I may have found the problem. Where the gas pistons impact against the bolt carrier, it appears that the metal has began to deform from the impacts.

I then realized that this portion of the bolt carrier is the rail in which it rides within the receiver. I think the rails have expanded due to deformation and are binding in the receiver. If you look at the outer edge of the bolt carrier rail, you can see where the finish has prematurely worn off around the front end.

Pulling the bolt to the rear, you can feel the bolt binding. Even with the bolt carrier tail out of the recoil spring assembly (remove the trigger group and pull the tail downward while inserting the bolt carrier group into the receiver.)

I have one of the 4 gas port barrels. I had originally broke one of the gas pistons within the first 50 rounds of owning this weapon. Now, as soon as I have some time, I'm going to call and return it to Benelli. Hopefully they'll replace the entire weapon since those swelled out rails have worn the inside of the receiver rails.

Honestly, the design is pretty poor for the impact site for the gas pistons. To ensure that it wasn't something else, I removed the top rail completely to prevent any type of binding. I also removed the bolt release.

No tacstar side saddles were on the weapon either. The weapon couldn't be any cleaner.

[HDRDKG]

I believe that was the issue with the older 4 port barrels. The barrel was designed for low recoil rounds and I have heard of the bolts actually breaking from the gas pistons slamming into the bolt. I have the newer 2 port barrel and no problems at all. I would trust my lfe on this weapon.

[MaxSecured]

I believe that was the issue with the older 4 port barrels. The barrel was designed for low recoil rounds and I have heard of the bolts actually breaking from the gas pistons slamming into the bolt. I have the newer 2 port barrel and no problems at all. I would trust my lfe on this weapon.

Hello HDRDKG,

Can you tell me the simplest way to determine if I have a 2 or 4 port barrel?

Thanks,

MaxSecured

[HDRDKG]

Take the barrel off the receiver and look down the chamber end. Best to have some white background. You will see the little holes inside the barrel where the gas system is located.

[ishmael]

I too have the 2 port barrel and have had no such problems, but I haven't shot it much. Has anyone had any similar problems with the two port barrel?

[HDRDKG]

Here you go. This shows that the Benelli M4 is one awsome weapon that seems to handle abuse very well.

 

http://www.benelliusa.com/forum/showthread.php?t=13618

[johnnywitt]

Two M4's, both 2 port bbl's. Both guns cleaned thoroughly before firing. The one receiver that was marked M4 LE, not a hiccup yet with regular loads and will even digest 7/8 oz. 20 gauge load weights with 3 1/4 gr. powder charge. The other gun, newer, gave me **** for about 100 rounds then runs like a champ now, but it won't cycle 7/8 oz. for sh*t. Benelli will probably give you another gun. They know about those 4 port guns. Hope they come through for ya.