M4 FTE, Pt II

[Nitro]

So, this has been an ongoing issue for me.  My M4 has been sporadically failing to extract for a while now.

Some background, I got it in Oct 2019 and have kept it mostly stock.  Mesa shell carrier & IWC light mount, everything else is original.  During my troubleshooting, I upgraded to a full length mag tube and wolff spring, which didn't fix it.  I've got about 400 rounds through it, all 00 or slugs.

Today at the range, I shot 50 rounds of Win Ranger 00 magnum.  First box of 25 went flawless, second box of 25, not so much.  I had 3 FTEs.  My best guess is the extractor itself is the problem.  I checked the whole gun when I got home, no loose components, bolt runs smooth.  I also cannot duplicate the issue from manually cycling the action with snap caps or live rounds, no matter how long I try.  I've tried shooting different brands (Winchester, Federal, Fiocchi, Hornady) and always the same result, starts off good then goes down hill.  The bolt stays back and the shell is left half in the chamber.  I clean and oil it after every range trip, she still won't play nice.

Oddly enough, it always seems to start when the gun warms up, not sure if that's coincidence or not. I've resisted sending it in to Benelli this long to see if I could sort it out on my own, obviously that's not going well.

Any input from those with experience (or ideas) is welcome.  I've attached a pic of the malfunction.

 

[Evolution]

No expert here either but, just using common sense it points me in the direction of the extractor too Or the spring that the extractor is under pressure with. OR maybe your chamber is slightly undersize or not polished well, so that when the chamber heats up and  the hulls are compressed tightly against the walls, it just makes it a hair too tight and the extractor slips off the head of the shell. Maybe a combination of the two things?

Just going by what you say that it doesn't occur until the barrel is good and hot. 

[John P.]

How much oil are you applying?  Getting those rails nice and wet?  This isn’t normal—mine has never malfunctioned in 13 years (most of it stationary in a safe, but still). 

[Nitro]

I do run it pretty wet, as I was instructed when I bought it.  Although I'm careful to keep it out of the pistons and mag tube as I was informed that could cause failures to feed.

The shells sticking in the chamber did occur to me the first few times this happened, however I ruled it out as I discovered that when it failed to extract I could tilt the muzzle up and shake the shell out of the chamber.  If that didn't work, I could catch the shell rim with a fingernail and easily clear it that way.  Point is it really takes minimal force to remove the spent shell when this happens, even when the barrel's hot.

I don't see any obvious damage to the extractor, but without another to compare it to, I have no idea if it's out of spec or something.

[John P.]

I wonder if maybe you could just send the bolt assembly to Benelli instead of the whole gun to see if things appear correct to them?

[RxArms]

I would service the extractor.  It is not normal to have the bolt back like that and a shell half way extracted.

do you have any friends with an M4?  If so, pop their bolt into your gun and see if it functions properly, if so, then you know it’s something off with your bolt assembly and most likely the extractor.

[Nitro]

Unfortunately, I don't know anyone personally that has an M4. Close as I can get is a friend that has a 1301.  I even asked my local range/gun shop if they had one used I could compare mine to, no luck.  As far a servicing the extractor, I've made sure it's clean and free of any carbon buildup.  It doesn't bind on the spring as far as I can tell, but then again, I'm no gunsmith.

I'm not sure Benelli would let me get away with just sending in the bolt assembly, even if that would be a alot easier and cheaper.  Although, I've never had to send a gun back to a manufacturer before.. 

[RxArms]

Might I suggest changing the extractor, is cheap enough to see if it works?

https://www.midwestgunworks.com/page/mgwi/prod/70037

changing the spring and pin also might be worth it.

Edited November 7, 2023 by RxArms

[Nitro]

I thought the extractor was held by a captive pin, I'll have to check that out.

Any ideas if Benelli would take issue with that should I end up having to send it in?

[Nitro]

Well, I was going to order a new extractor and spring but now I find both are out of stock at MGW. It's looking more like I'll be sending it to Benelli.

Anyone have any recent experience with their CS? How are they fairing these days?

[EzGoingKev]

On 11/6/2023 at 11:37 PM, Nitro said:

Unfortunately, I don't know anyone personally that has an M4.

Where are you located?

[John P.]

They’re in stock at https://www.gunpartscorp.com/gun-manufacturer/benelli/shotguns-benelli/semi-auto-shotguns/m4-super-90 if you still want to try.

[Nitro]

Thanks, I'll check that out.

I took a closer look at the extractor and barrel, there's some wear but nothing that seems to be impeding function.

[StrangerDanger]

Looking at your photographs, the extractor claw looks to be rounded over on one side of the claw, is this accurate? If so, then this may be the source of your issue.

Replacing the extractor claw can be difficult. The pin is almost a blind pin. I say almost since you can access the side you need to tap from, but you essentially need a curved punch. Punches don't like curving and generally break making it a consumable tool. If you need help with this, I can take care of it for you if you like.

[Nitro]

Indeed it is rounded off at the bottom edge.  I was wondering if this was part of the design, a factory defect, or if it was damaged by something I did and never noticed.  Looking at the bolt assembly, I understand what you mean about it being a difficult replacement.  I was going to try to contact Benelli on Monday to see what they have to say about it.

I really appreciate your offer to replace it. Depending on what Benelli has to say, I may take you up on that.  Thank you.

Figures I would find a way to break something the Marines couldn't break...

[StrangerDanger]

We saw a lot of quality control issues come out of Benelli during the Covid era. 
 

All of the extractors I looked at have a pretty hard 90* corner on both sides with maybe a light chamfer to knock the edge down. 
 

My concern is the damage is deeper than the extractor. Like the wear on the extractor is the symptom of something else being out of spec. Could be the bolt head. Could be the bolt carrier. Could even be the barrel assembly but less likely. 

 

Without being able to hot swap parts and live firing it, you’ll just be guessing. So if Benelli will warranty it, you’d be best served going that route. 

[Nitro]

Thank you for the information and advice.  Hopefully, Benelli is willing to play ball on the warranty.

[Nitro]

Spoke with a Benelli rep and he advised sending it in.  He also agreed that it's most likely and extractor and/or extractor cut issue.  It's going to be at least a six week turnaround, minimum, apparently because it's hunting season and the M4 ain't a hunting gun but hopefully they can sort it out and get it running properly.

Thanks for all the replies, I'll keep updating when I know more.

 

[Nitro]

Update..

Got my M4 back from Benelli after a little over two months (Dec 4th-Feb 14th) and finally got it to the range.  I'm happy to report I ran 118 shells of 00 buck from a few brands, mostly Winchester, without a single failure.

According to the report from the tech they changed out the extractor and deepened the extractor cut in the barrel extension.

I wish I could say my trust in my M4 has been completely restored, but I think its going to take a few more range trips for that. I'm a pessimist, I know. More like 98% restored..;)

Thanks again to everyone for all the previous input.