Unobtanium

I would only use it once, buy replacements from brownells.

Did they ever occur using a different type of ammunition?

Was the weapon 100% stock in every way? Is it still stock in every way now, and does it still do this? If not, what was changed?

I have a chrome-lined bore

Yeah, this will work as it's not a "rocket science" type part, but I can understand OP's anguish, as I am OCD myself. OP, while you are at this, order yourself a few O-rings for the gas plugs, and an O-ring for your firing-pin retaining pin. You will thank me later when you nick one being careless. http://www.brownells.com/.aspx/pid=23713/Product/TRIGGER-GUARD-PIN-SPRING http://www.brownells.com/.aspx/pid=23649/Product/GAS-PLUG-O-RING http://www.brownells.com/.aspx/pid=6388/Product/FIRING-PIN-RETAINING-PIN-O-RING

It would be hard not to considering that it's functionally the same as an 11707 with Kip's magazine tube, a US hammer, and a C-stock with a fancy coating which seems to be a mixed blessing so-far.

Both are great products. The carriercomp tube fully loaded is only slightly heavier than the unloaded steel tube. It is also corrosion proof, nearly. To me, it was worth it.

If nothing else, someone in the US can probably gift it to you. It's just a piece of pipe...probably necessary for a science-project your kid is working on.

Yes, but then you add rail-panels and a VFG because the M80 is awkward to grab, and the light itself, and you have more weight than you bargained for.

I am contemplating placing a lock-washer similar to the M4/M16 variant found in the PG of that weapon system under the washer of the Urbino, and then a "crush" type lock-washer between the bolt and the supplied washer. I think that might do some good.

Doesn't get any better than that! This is where I sourced the above info on his setup: http://www.brianenos.com/forums/index.php?showtopic=150964&view=findpost&p=1692132

PS. I do not believe that a properly spec'ed M4 is capable of a non-user induced or maintenance-related malfunction using full-power ammunition, so I tracked you all over the internet and found that you are using a Nordic Components spring that you have trimmed, as well as a total mag-tube length to accommodate 9 shots, consisting of a +2 factory extension on your OEM 5-shot tube, and then a +2 extension on top of that. This is likely the source of your problem. Buying the spring from Kip SHOULD fix your issue, although it is designed for a 7-shot tube, Kip has opined in the past that it will work for a 9-shot tube. It is certainly better than what you are currently running.

The small spring is from Brownells. Are you saying your 11703 spring was smaller yet? http://www.brownells.com/.aspx/pid=6248/Product/RECOIL-SPRING-STANDARD-AFTER-S-N-M293830

I would be very interested if others using your chokes posted their results, as well, as each shotgun seems different.

Very nice!

Solid deal. Looks like the guy would just rather have an m4 carbine. Just keep her up, or try AR15.com I also suggest maybe buying a geissele hammer, upping the price $50-60, and selling as 922r out of the box.

I looked further into your issue. The Field stock has a screw in it that interfaces with the "plug" in the buffer tube. If you remove the stock and *possibly* the snap-ring and change the orientation of this plug by 90* or 180*, you very well could fix the issue you are having. It's worth a shot!

I have an M1014. I ordered an "M4S90/Common Parts" recoil spring from Brownells. It is the only one they offer for the M4. I measured the new spring against my M1014 spring (has had a few rounds through it by now). Surprise. My M1014 spring is still noticeably longer. It has 64 coils while the one from Brownells has 65. Further, I mic'ed the diameter. M1014=0.47", M4=0.45". My M1014 cycles loads as light as 2.75 dram. However, based on posts I have read, the M1014 is historically the most finicky, and indeed my M1014 did eject light loads rather weakly when I first got it, although it never had any failures. If anyone has a micrometer or is curious, I would be interested to see how your M1014 or M4S90 spring OEM compares. It will be a good chance for you to clean and lubricate the tube. I recommend TW25B for this process. Less friction in the recoil tube= better reliability, especially with light loads. I also noted that my recoil "buffer" is chrome-plated. I don't remember if the M4S90s I had were or not.

+1 PLEASE DESCRIBE IN DETAIL WHAT HAPPENS. I will provide an example, that happened to me: -Weapon: M4S90 -Variation from OEM: OEM Steel full-length magazine tube (can't get them anymore, don't ask), OEM spring/follower. -Ammunition involved in failure: Winchester 12-pellet "magnum" 2.75" buckshot. 3" #4 Remington buckshot. -Condition of weapon at time of failure: Firing/just fired next to last round in magazine. 1 round available in the weapon to be fired. -Weapon condition at time of failure: Relatively clean, well-lubed. -Situation: Fired slow-fire correctly from the shoulder. -Failure: Bolt locked back, round either on follower or stuck in mag-tube. Follower is always "down" just like the gun had locked back on an empty chamber. There is one round remaining in the weapon. Solution/Conclusion: Magazine spring is not strong enough. Rationale: the shells move freely in the magazine tube. The less shells, the less spring pressure. When a healthy shell (2.75" 12-pellet buck or 3" #4 buck) is fired, the inertia of the weapon causes it to move backward. The shell, having mass and being at rest, does not wish to move (physics). It compresses the spring in the tube while the weapon around it moves backwards. The bolt cycles before the spring overcomes the resistance provided by the shell under heavy recoil. The above failure resulted. Solution: Back then, it was ordering a M1S90 Military spring. Now it is just buying one of Kip's Ti tubes which comes with a custom spring which I have found to perform flawlessly. Kip formerly sold these springs individually, I am not sure if this is still his practice, but he is a great guy to do business with, and if you are running a full-length magazine tube from anyone but Kip or FFT, and using the supplied spring, I would suspect that this might be the issue. (SOCOMguy also made/makes quality products, but I am unaware of what spring, if any, he offers with them). ______________________ The above might give you some insight into the issue. It is a thorough analysis of a similar problem I had back in 2008 or so.

Mine showed wear in a few dozen rounds or so. Would it have died sooner or later? I doubt it. However, I feel that Kip's product is far superior.

Should be indicated on boxing.

As long as its not reduced recoil.

Is there a round on the follower?what ammo, mag, and mag spring are in use?

Factory stock is long, but it's the best made thing out there. You can try the Urbino, but it forgoes Benelli's awesome system and attatches with a screw. I'm not really a fan of it as it shoots loose easily enough if you don't locktite it. If you do, it's on for keeps because of the crappy slot-screw they use. If they have a beefy hex-head maybe not such an issue. Anyway, just my experience with it and what I have read from others. Kip... http://www.carriercomp.com