Unobtanium

It indeed looks like an 11721, however, as far as I am aware, those do not have fixed chokes. Can you take a picture of the end of the barrel to verify? I am very interested in seeing this, if it does indeed, as that is part of why I bought my M1014.

Hard to explain, frustrating to play with in the living-room, completely intuitive in action.

I suggest a possible modification of user technique. I find many people pull the shotgun into their bodies with both hands, along the lines we all hear as children "Hold that shotgun tight or it will break your arm!" We develop a death-grip/hug type mentality when we hold our shotguns. Especially the 12ga. However, try this. With your trigger-pulling hand, pull the gun toward your body, firm against you. With your fore-arm holding hand, pull the gun away from you. Creating a tug-of-war. Your forearm will be a shock-absorber, and your trigger-hand will keep the gun firm to the body---but not rib-crushing. It should be a game of tug-of-war that your trigger-pulling hand barely wins, but that should not cause trembling or shaking. Stop it just short of that. Further, lean slightly into the weapon. 60-65% of your weight on your front foot, torso leaned slightly over your center of gravity, into the weapon, to create this bias. Pretend you are poking the muzzle into your target. An antagonistic "poke" delivering type stance. Nothing exaggerated, but I word it this way so that you get a visual. In fact, here: Second soldier from the camera, like that (notice the first soldier appears to be a girl ): Report back letting us know how the recoil pad functions after said technique modification. Play with it, 60/40, 70/30, pull-push etc. Try some controlled pairs. Let us know if it helps. I am inclined to think that your shot-to-shot recovery time will decrease greatly, as will the pounding your chest takes.

Here is the TDS for Loctite 243 http://tds.loctite.com/tds5/docs/243%20NEW-EN.PDF Compare it to the TDS for Loctite 242, and pay special attention to the bond strengths on Stainless and other more inert metals. http://tds.loctite.com/tds5/docs/242-EN.pdf

For semi-permanent install: Loctite 243 or Loctite 242 AND PRIMER, or Rocksett (unsure of how permanent this is in this application, heat WILL NOT WORK to remove it. Rocksett claims is water-soluble. ) or Vibratite VC-3 (very impermanent, but should hold it solid per claims, ships with Gearscout mounts and is used on M1Abrams turret bolts). Loctite 242 by itself isn't going to work.

The only currently produced M4 that I am aware of that has a fixed choke is the SBS. Do you have a factory SBS M4?

If the handguards he is using are slightly "longer" and prevent complete seating of the barrel in the receiver, then they are taking the brunt of the recoil instead of the receiver. They are polymer I bet, and they flex. This takes tension off of the detent/mag-cap. This allows movement of the mag-cap.

Replace your aftermarket handguards with the OEM handguards and repeat testing. Let us know if the problem persists. I do not think it will. Other than that, I have read this thread and am at a loss. I assume that the problem is not you, and I cannot figure out how it is the weapon, if the detent is present, and nothing looks grossly "wrong", and you are getting audible and physical feed-back when you tighten the cap. Take a picture of the barrel/receiver joint after it is installed, and take a picture of the detent and cap where we can see the detent, see the teeth. Take a picture up into the receiver's "ceiling" with the trigger-group removed. Take a picture of the handguards with the shotgun upside down (fully assembled), and looking down on them right-side up. This will allow everyone to see every possible failure point except for something really outlandish. Those are the only areas that I can think are the issue. The only other issue is that you are using the OEM 2-piece setup for the mag-tube with the spacer, and your spacer is loose, so no-matter how tight you get the mag-tube, the spacer being loose negates it. I studied that as a failure point, and it is one. Insure that the spacer is tight to the magazine tube, if that is your setup, before you tighten the cap.

The tolerances of Kip's initial tubes were different than his current tubes. Kip had to begin making the tubes with more tolerance between the threaded portion and the receiver because a few people could not physically install their tubes. Every time he got a return tube because the Benelli receiver would not accept it, he loosened the fit by an infinitesimal amount. This is because Benelli's tolerances are not as "good" as Kip's. The receivers that would not work were "outliers" that he had not encountered until that time, but if one exists, another likely does, so he took that into consideration in future production runs. The reason I am a fan of Kip's current tubes in lieu of his past production runs (and not scrambling to get an older "tighter" tube) is that they are ever so slightly thicker than in the past. They are literally the strongest Ti magazine tube on the market, bar none. Please note that his +- tolerance standards have not changed. He is just adapting to Benelli's variances so that all of his customers can use his products. I first attached my magazine tube with Mxloc 42, a generic version of Loctite 242 which shares its formula. I used only 1 small drop. By the end of 100 rounds at the range, my magazine tube had come loose. I then used A LOT of the stuff when I re-attached it. I let it dry for 24 hours. During that 24 hours, I researched anaerobic thread-lockers. I did a TON! of research, discovering that the Ti and anodized Al were all but non-reactive. This, coupled with the smooth surface of the Ti threads prevents any kind of meaningful bond. The most you will accomplish is that when the 242 hardens, it will have created a near interference fit for the threads. It won't adhere at all. This is what about 30 seconds with a heat-gun and a VERY SMALL amount of torque from my hands resulted in after a 24 hour cure time. I doubt the heat did much. As a point of reference, I cannot budge my current setup, even if I torque on it as hard as I can. *Note the perfectly clean threads. It did adhere some to the receiver. Not at all to the Ti tube. I used acetone to prep both surfaces. UN-torquing the tube took what felt like the same torque as I used to tighten it when wet. It is my conclusion that the best adhesives for this application are Rocksett, Vibratite VC-3, and Loctite 243. Rocksett is water soluble and has a low yielding torque, but is nearly heat-proof, is not substrate dependent, and acts as a resonance damper. Common use is attaching suppressor mounts. Loctite 243 is like "Super 242". It needs no primer, and is a little more resilient in every way. Common use is industrial. Vibratite VC-3 is a different type of thread-locker. It is a very very viscous vibration damper. Common use: M1 Abram's turret. Regarding ease of removal, I have no experience with Rocksett, but have heard both that it is easy to remove, and very difficult. I will rank it as the "most permanent", followed by 243, followed by VC-3, which is meant specifically for easy removal. Gearscout includes it with their mounts, as do a few others. *** Stainless, most shiny plated/coated bolts or nuts, Ti, Anodized Al etc. are all non-reactive, along with a few other metals. FYI, you should use a primer with 242, or use 243, when trying to bond these metals to another non-reactive.

You've already done a ton for the community and myself, Kip! I am sorry sending that 243 to you took so long on my part, glad you received it! Loctite 242 CAN be used, but only if the correct Loctite primer is ALSO used. By itself, you might as well spit on it and screw it into the receiver.

Just a PSA, but use Loctite 243 if your install is to be "semi-permanent" (i.e. not removed after every range trip). Loctite 242 does not play well with Ti and anodized Al. Very little/no adhesion.

The trigger feels about the same. IF an issue arises, it is on Benelli's part. I have never heard of a Geissele component having an issue.

The hammer should not cause any issues. Geissele is actually the company that is replacing many of the KAC fire control groups in military weapons. Their stuff is solid, and has a track record for being successful.

The only M4S90's you will find like this in stores (I mean to say, with a real magazine tube, not the spacer), are the H20's, which have a coating, which qualifies them as "American made" through a loop inadvertently created in the system by forcing re-finishers to have Type 7 FFL, thus making them "manufacturers". The feds screwed themselves. Receiver Barrel Bolt Bolt carrier Gas piston Trigger housing Trigger Hammer Disconnector Buttstock (with integral pistol grip) Forearm/handguard (forend) Magazine body (One part you will replace with the mag-tube) Follower (Another...) You still have 11 parts and are not 922r Compliant. Even if you don't choose to add the C-stock. The only way this is now legal is if you add the Field stock (no PG). TO make this legal, people usually add handguards, or hammer. I chose to add the hammer, because I am a huge Geissele fan and have their triggers in all my M4gery's.

Because people want to be 922r legal if they can. With a PG stock, you're not 922r legal unless you have this, or another part.

I have waited anywhere from 2 weeks to 2 months.

Bought components and made it. Total cost was around $80 + Coating. Notice how it matches my mag-tube... You like it? You can have one, as well! http://tac2.net/index.php?template=bbr + http://www.shootersconnectionstore.com/Shooters-Connection-Mag-Release-Button-P536.aspx Their picture is crappy. It is actually shiny/stainless, but their picture doesn't show this. Mine is coated to match my mag tube.

You can do so from his website. http://shop.carriercomp.com/category.sc?categoryId=4 Be prepared for a wait.

+1, I think the GG&G bolt release is even a bit large, for my taste, and opted for a custom setup that was smaller:

I have owned the large titanium bolt handle from FF, which weighs in in the mid teens, IIRC, and the action did feel much less robust. It's definitely not obsessive, especially if you want to shoot light birdshot for practice or something. Also, the bolt-carrier should recoil straight back. It is symmetrical for this reason. 2 pistons--one on either side, equal weighting, but then you have this piece of metal sticking out of one side of it...throws balance off, creates ever-so-slight un-even wear, and causes it to recoil less smoothly than otherwise possible. Why don't you go shooting with some light birdshot and after charging the weapon REMOVE your big fat bolt-handle and see how it feels. I promise you will want to ditch the thing, after that. Lighter is definitely better because it not-only adds weight, but also screws up the dynamic function of the thing.

It's difficult. What do you want to ask him?

Yes, me personally. It occurred during rapid-fire. UN-aimed magazine dump "for fun". I just outran the gun. It has happened maybe 3 times over the 4 M4 shotguns I have owned over the years, but the first time it happened, it was weird. I thought something was broken, or that I had not allowed the trigger to re-set. I then had it happen again, and before doing anything else, let completely go of the trigger, checked that it had a chance to reset, thought about things, checked the chamber, etc. Definitely benelli click, as it were. The first time I had just gotten the gun back into action and wondered about it later.

The Benelli trigger system is a poor design in some aspects. The disconnector setup allows you to pull the trigger and release the trigger with the bolt still about 1/2" or so out of battery.

Several times. Not on my M1014 yet, though.

Just wait. People will sell/give them away on here from time to time as they upgrade to full-length mag-tubes. Cruise AR15.com for that same, as well. It's like $50 or less from a person, $$$ from Brownells or Benelli.