New M4 Won’t cycle properly

[Nmthree]

Bought an M4 about 2 months ago - love it…when it cycles properly.

Took the gun out of the box, ran some Remington 1200 fps, 1oz shells (bird shot) through it. Every 4th or 5th round, a shell would get stuck in the carrier.

Called Benelli and I was told, the rounds weren’t heavy enough and FPS was too low. I was also told the gun was probably on a ship for 3 months…clean it, oil it and get ammo that was at least 1250 fps and 1 1/8 oz.

Cleaned it, oiled it. Bought Winchester 1325 1 1/8 00 & Federal 1 1/8 1500 fps. 
 

Today shot about 75 rounds through it and shells keep getting stuck in the carrier. Any advice. See picture attached (of shells getting stuck in the carrier.

Thanks in advance for your help.

 

[Dkay67]

What size magazine tube does this have, and if a 7 round, did you change the spring out?

Edited December 19, 2021 by Dkay67

[Ben elLes]

Also run like 2 or 3 hundred rounds of buck / slugs through it.  That’s what it is made for so start with that.  Bird shot runs clean through my older one now.  Still breaking in the second.

[Unobtanium]

I see a crossbolt going through a receiver. This is a no no in my book. You could be pinching the receiver or distorting it in a way that is causing retardation of the carrier's movement. I am not sure this is the problem, but when someone has an issue with a gun as proven as the M1014, and it's  not in factory configuration, I opt to return it to such, operationally, before further diagnosis.

 

Further, the mag tube/spring comment above is very on point, as well.

Edited December 19, 2021 by Unobtanium

[Milspec]

Yeah, what is up with that bolt.  What's going on there?

[Unobtanium]

40 minutes ago, Milspec said:

Yeah, what is up with that bolt.  What's going on there?

Its to attach the side saddle, and its proven to cause issues in other guns.

[RJHUB]

Also make sure that bolt release spring is in place.

I would check all things that were not factory.

[CAUS]

47 minutes ago, Unobtanium said:

Its to attach the side saddle, and its proven to cause issues in other guns.

How does the 3rd-party trigger guard pin cause the problem? Wrong size? Thanks!

 

[CAUS]

My two cents is to not modify anything in a new gun. Run a few hundred rounds first to make sure it runs smoothly. Then, change one thing at a time, unless it has nothing to do with the shooting part.  

[Evolution]

2 hours ago, CAUS said:

How does the 3rd-party trigger guard pin cause the problem? Wrong size? Thanks!

 

The OEM trigger group retaining pin is just a pin, held in place at the head with a cir-clip and retainer. It does not have the capacity to pinch or squeeze the receiver's sides in. The receiver is very thin in that area.

You would think that the trigger housing might prevent that from happening but who knows? If the cross bolt is cranked on.

Edited December 19, 2021 by Evolution

[StreetSweeper56]

Easy way to check, remove the bolt holding the side saddle and replace it with the OEM retaining pin. My guess is that will, in fact, fix the problem.

[Ben elLes]

I had some problems with an extended carrier doing the same thing… you got one of those on there?

[StrangerDanger]

If that’s a Tacstar side saddle, it’s a notorious piece of shit that will definitely squeeze the receiver if tightened too much. Not tightened enough and it falls apart. Then it starts scratching up your receiver.

Any aftermarket shell elevators in use?

I’d take the magazine tube apart and clean it well inside. Do not apply oil inside the magazine tube at all. I’d recommend making a polishing jig for the magazine tube. I put a 12 gauge cleaning rod in my drill gun, then wrap fine steel wool around a 12 gauge chamber brush. Then go to town up and down the inside of the magazine tube for 5 minutes. Clean out the residue and admire the mirror finished magazine tube. Note the difference in sound once you reinstall the spring and follower. The magazine spring won’t be fighting the resistance inside the magazine tube as much so that it can deliver more of the spring energy to loading shells onto the elevator. This is particularly important when it is the last round or two being loaded from the magazine. The polishing can be done on steel, titanium or even the Briley carbon fiber magazine tubes. 

[StreetSweeper56]

1 hour ago, StrangerDanger said:

If that’s a Tacstar side saddle, it’s a notorious piece of shit that will definitely squeeze the receiver if tightened too much. Not tightened enough and it falls apart. Then it starts scratching up your receiver.

Any aftermarket shell elevators in use?

I’d take the magazine tube apart and clean it well inside. Do not apply oil inside the magazine tube at all. I’d recommend making a polishing jig for the magazine tube. I put a 12 gauge cleaning rod in my drill gun, then wrap fine steel wool around a 12 gauge chamber brush. Then go to town up and down the inside of the magazine tube for 5 minutes. Clean out the residue and admire the mirror finished magazine tube. Note the difference in sound once you reinstall the spring and follower. The magazine spring won’t be fighting the resistance inside the magazine tube as much so that it can deliver more of the spring energy to loading shells onto the elevator. This is particularly important when it is the last round or two being loaded from the magazine. The polishing can be done on steel, titanium or even the Briley carbon fiber magazine tubes. 

That is genius right there!

[ede2301]

I had a similar issue with my new M4, about 2-3 times in every 20-25 shells a shell would get stuck on the carrier ramp. Basically at the time it seemed like the bolt carrier group didn’t have enough momentum to push it forward and load it.  In each instance I was able to either tap the bottom of the shell carrier or the nudge the bolt handle forward and it would load the shell. Initially I thought maybe it needed shells with a little more velocity but this seemed to occur regardless of the type of shells I was using and always towards the end of the magazine usually around shell 5, 6, or 7.  I tried some Federal 3 Dram 1-1/8 ounce #8 field loads, Federal Power Shock 00 Buck, Winchester 00 Buck Military Surplus (Brown Box), Wolf Power Shot 00 Buck, and a few Federal Law Enforcement slugs, nothing low velocity and nothing low recoil and all 2.75" shells.  When I say a few total shell count was around 200.   

I went ahead and took the entire shotgun apart, barrel, magazine tube, gas pistons, plugs, bolt, trigger group/housing, bolt carrier, and thoroughly cleaned and oiled it, sans the gas pistons which the manual states not to oil.  Everything looked in good working order but still the issue persisted. Even with dummy shells and testing on the bench it would occur once or twice out of every 3-4 magazines.

The aftermarket parts I swapped are listed here:
Benelli OEM 7 rd mag tube installed, for 922r purposes I put in the FFT trigger kit (trigger, hammer, disconnector with springs), one of the FFT Mag Followers, an A&S Trigger Housing (since I had to take the whole trigger pack apart anyway to put in the FFT Kit I figured I might as well get rid of the polymer housing plus gain one 922R part), a FFT Wolff Magazine Spring, and FFT Handguard.  I also swapped the recoil tube for a 3 position tube but that's Benelli factory.  Basically I've added parts to stay in compliance plus the mag spring but nothing superfluous.  No side saddles no aftermarket Bolt Release Buttons, etc…

Here was the fix (at least for mine M4 anyway) if anyone else is having this issue, Per Stranger Danger's guidance I went ahead and polished the inside of the magazine tube, used some #1 Steel Wool wrapped around a brass 12 gauge bore brush and attached that to my Drill.  Went back and forth for about 20 minutes then switched to a #0000 polishing steel wool and did another 20-30 minutes.  That mag tube is smooth as glass. 

Even went ahead and used some light polishing compound on a cotton wheel on the Dremel on the ridges of the Magazine Follower which is also smooth as butter at this point.  However that didn't completely resolve the issue but what did was removing the FFT Wolff Premium Spring.  For some reason my M4 was just not happy with the FFT Wolff Premium Spring.  I switched over to a Carrier Comp premium spring (oddly also a Wolff Spring but made to different specs) and I am rocking shells up the feed ramp at this point.  Even the original factory spring is working.  Interestingly the OEM Spring, and the FFT Spring are close in length, with the FFT being just slightly longer maybe 2-3 inches.  The Carrier Comp Spring is over a foot longer then both the factory and the FFT Spring.  I talked to Todd over at FFT and to his credit he refunded me the price on the spring I bought from him since it just doesn’t seem to work in my gun.  Excellent Customer Service and that was certainly appreciated!      

In summary, I’d ditch the side saddle, and possibly for testing purposes even the oversized bolt release button.  Then polish the magazine tube, polish the ridges on the follower, and give the Carrier Comp Spring a try.  I’ve not had this problem come up since then and I’m running all of the aforementioned rounds without problems.  Best of luck!   

[Evolution]

^^^^Doesn't surprise me at all that your apparent issue was the spring. When you get down to the last couple of rounds if the spring tension or power remaining is not sufficient enough to throw next the shell well back onto the carrier, it stops up the gun.

Personally, I stay away from FFT supplied stuff.