etale

tactical1 has a good point about the grease. I would definitely *NOT* use grease in the hammer plunger/ spring area, as it is incompressible and too viscous to rapidly expunge out the vent hole. In fact, it's a common automotive technique to pull clutch bearings by packing the recess with grease and hammering in a plunger (e.g. solid steel rod) with interference fit to the inner bearing: the force of the plunger is transmitted through the grease to the bearing outer race, thus driving it out of its recess. Point being: if there is captive grease below the plunger when the hammer strikes it, the plunger will be prevented from fully depressing into its recess. Something has to give way, and given how hard the hammer is, it's going to be the plunger cap. I just run a very light lubricant (e.g. machinegunner's lube from LaRue) throughout my trigger group, *except* for the sear contact/ engagement points, where a small amount of grease is appropriate.

Definitely not right. I would call Benelli on this, as it looks like a defective part. I have about 450 rounds through mine and my hammer spring cap is virtually pristine.

I have not spoken to FFT about the hammer deformations I observed. FFT is an upstanding company, and I am sure that they will stand behind their products. That said, I feel bad about asking for a refund on the Hammer, and would be happier exchanging it. If it is a heat treat issue (quenching too slowly/ at too low a temerature or tempering too long) it should be easy to resolve quickly. Hardness issues can be caused by more serious problems, such as defects in the steel itself (carbon content too low, impurities, etc.) I'd be interested in what type of steel they are using (S series?). Of course, I still have no firm judgement as to whether the deformations/ dents in the hammer that we are seeing is significant from a functional viewpoint, but it is disconcerting in comparison that Stranger Danger's OEM hammer is un-dented/ deformed after..... is it 13K + rounds, if I remember?

Mine is in exactly the same position as Crofton's. My m4 is 2010 production, I think (bought in early 2011).

Hookster--You are very welcome. StrangerDanger--Thanks. The marks on the hammer are definitely dings/ deformations, and not just surface abrasion. Where the hammer strikes the firing pin there should be a nick visible in one of the pictures. This area has been deformed from an initial thickness of 0.1470 in (measured across the body of the hammer right below the nick) to 0.1530 in (measured right at the nick), for a change of 0.006 in. It seems as if repeated contact with the firing pin has "pancaked out" this portion of the hammer a little, if that makes sense as a description. The nick itself is about 0.04 in at its widest, and the indent is definitely noticeable while running a fingernail across this portion of the hammer. Again, I do not know if this is significant in terms of long-term functionality/ reliability, only that the Geissele/ Carrier Comp and OEM units show no such deformation/ dinging. I agree with you that it is a hardness issue, though not having access to a Rockwell tester, I can neither confirm nor refute our suspicions. As for trigger pull, my (limited) impression was that the FFT trigger with Geissele/ CarrierComp hammer resulted in a trigger pull comparable to that of the full FFT trigger pack, and noticeably lighter than with the OEM trigger and Geissele hammer. That said, I took no measurements on this matter. I will be very interested to hear about the impact of your testing on the FFT hammer (if any). It could well be that my hammer was tempered too long or quenched too slowly for some reason... Mr. Shotgun---I am currently using the FFT trigger and disconnector with the Geissele/ CarrierComp Hammer, and all the usual function checks (as described in the FFT instructions, or in StrangerDanger's earlier post in this thread) check out exactly as they should. That said, I have yet to hit the range with this combo.

I put 100+ rounds of target loads through my m4 yesterday with the new FFT trigger package and I wanted to share some observations: First let me say that the FFT components installed easily, and functioned without any flaws through all 100+ rounds. Trigger pull is lighter and crisper. I am very excited to have acquired 3 US parts for 922r compliance, and agree with the assessments here that the FFT components seem to be well-made and finished. During routing cleaning of my m4 after range time, I noticed that the FFT hammer suffered some dents/ deformations from striking the firing pin and/or from the BCG cocking the hammer.. I was very surprised by this, as neither my OEM Benelli hammer nor my Geissele US-made hammer had any dents after 100+ rounds each, though both did "shine up" a bit (loss of surface coating) where the hammer hits the firing pin/ BCG. Below are some pictures I took of each of the hammers (FFT, OEM, Geissele): [ATTACH=CONFIG]1295[/ATTACH] [ATTACH=CONFIG]1296[/ATTACH] [ATTACH=CONFIG]1297[/ATTACH] Here are the three hammers together: [ATTACH=CONFIG]1298[/ATTACH] Geissele's website says that their hammer is EDM cut and hardened from S7 tool steel stock, while FFT says " wire EDM from ground bar stock high-impact premium tool steel". Usually, S7 is used in high-impact applications, and I would not be surprised if the FFT hammer is S7 as well, given what they say. That said, it would seem based on my experiences that the Geissele hammer and the OEM hammer are both harder than the FFT hammer, as they incurred no dents/ dings. The surface coating on the Geissele hammer also seems to be slightly more abrasion resistant than either the OEM or FFT hammers: the latter two have some abrasion marks from where the hammer rides the hammer spring/ plunger. [ATTACH=CONFIG]1299[/ATTACH] The Geissele is center. The sears are also much sharper/ crisper on the Geissele than either the FFT or the OEM. Careful measurements on the digital calipers also revealed that the bore of the Geissele is 0.2400 in, while both FFT and OEM clock in at 0.2515 in, making the Geissele a slightly snugger fit; this results in slightly less lateral play of the Geissele hammer. Does any of this matter? I really do not know. That said, I was irked enough that my new FFT hammer was getting dents after less than 125 rounds of light target loads that I re-installed the Geissele unit. I also wanted to report on two other observations. The first is that while the OEM and FFT disconnectors and hammers are functionally identical, the triggers are slightly different. In fact, I suspect that the geometry of the FFT trigger is a bit different (deeper bore for the trigger spring, perhaps?). Close inspection reveals that with the OEM trigger and either OEM or FFT disconnecter (and any of the three hammers), when the hammer is cocked there is definite clearance between the hammer and disconnector. I could fit two sheets of paper in the gap, making for a clearance of about 0.008 in. In contrast, when the FFT trigger is installed with any of the disconnectors and any hammer, the hammer *always* contacts the disconnector on its rearward trajectory. This contact is very small, and not enough to engage the disconnector sear when the trigger is at rest, but movement of the disconnector is noticeable. This may explain some of the difference in feel between the two triggers. I would be curious to hear whether or not there are m4 users out there with the FFT trigger installed who are still able to "beat the disconnector" during rapid fire exercises (as StrangerDanger has previously reported), as that 0.008+ in could well cause the disconnector to engage marginally sooner/ longer. Finally, I wanted to note that the FFT trigger, hammer, and disconnector pin holes are all chamfered, in contrast to the OEM and Geissele units. This perhaps makes installation slightly easier (though I didn't find this to be the case), but it also makes for slightly more lateral play, at least in theory. In conclusion, I want to reiterate that the FFT offerings seem to be of high-quality and function exactly as they are supposed to, at least in my rather limited testing. I am well-aware that FFT function checked their trigger control components extensively, and that my observations more than likely amount to inconsequential minutiae. For these reasons, they should not be interpreted as any kind of critique of the FFT components; they are only observations at this point in time. I would be interested to hear if anyone else can confirm/ duplicate my observations regarding the FFT hammer and trigger.

Thanks, Stranger; I always enjoy your reviews/ comments. I just got my FFT trigger pack today and am looking forward to the install (currently has the Geissele/ CC hammer).... no doubt it will be much easier with the detailed guide you provided.

Thanks BigHat for the thoughts and sonny27 for the suggestion to call Geissele. I spoke with an engineer at Geissele who confirmed that the lack of uniformity in the oxide coating is a byproduct of the manufacturing process, and not a defect. Specifically, the sear lips as well as the hammer pivot hole are wire EDM cut, which leaves a different surface texture than the rest of the manufacturing process. After hardening, this texture takes the black oxide (blueing) differently from the rest of the hammer, resulting in a reddish-brown hue, rather than the slick jet-black on the rest of the hammer. As suspected, I did indeed find the sear lips to be crisper and sharper on the Geissele than the OEM, and noted that black-oxide has superior wear and abrasion resistance to Benelli's phosphate coating. Now if only Geissele would make a drop-in trigger unit for the m4....

I just installed the Geissele US-made hammer (acquired through Carriercomp) on my m4, and it functions flawlessly so far. Upon close inspection, the Geissele unit I received differs slightly from the Benelli OEM in several respects. One such difference is that the surface finish on the Geissele does not coat the entire hammer: there is a small patch directly behind the rear sear (the one that engages the disconnector) which seems to be bare tool steel. It may be that the corresponding region by the front sear (trigger engagement) is similarly un-coated, though I did not note this. Did anyone else observe this on their Geissele hammer? Is this a design feature, or is the surface coating on my hammer defective? Does anyone know how the Geissele is coated (Benelli coats theirs with a phosphate, I think)?

It's called complying with the law. The fines and penalties associated with taking game with an illegal device greatly outweigh whatever benefit you seem to imply would be associated with not plugging the magazine. I use my m4 for a lot of different things, so it it's important to me that it be as versatile as my interests. So what is it you wanted to say, exactly?

As stated in the post (part 2 of 2), I wanted a plug that can be removed and installed *without* any tools (e.g. c-clip pliers to remove/ install the mag spring retainer). Neither Benelli nor anyone else sells anything like that. As for m4 specific limiters on the market, it isn't so clear to me that there is one, though apparently this would work: http://www.brownells.com/.aspx/pid=6463/Product/PLUG__3_SHOT__STANDARD_MAGAZINE See post 2 or 2 for another option. Again, nothing on the market that doesn't require removing the mag spring retainer. Also: cost to make my plug: $4.19. Less than half the cost of anything out there that might work. So yes, lol indeed.

Thanks much for the reference pic! It looks like installation of the factory limiter requires removal of the mag spring retainer clip. Is that the case? I had specifically wanted a limiter that would require no tools (e.g. c-clip pliers) to remove or install...

Here are the promised installation pictures (See M4 Magazine Plug (post 1 of 2) ). [ATTACH=CONFIG]916[/ATTACH][ATTACH=CONFIG]917[/ATTACH][ATTACH=CONFIG]918[/ATTACH] I don't know how much the plug weighs (no scale), but it's pretty damn light. Could be lightened with an aluminum (or titanium or CF...) plug, naturally. Length is perfect for a 2-round (2.75 or 3" shells) limit. Of course, *technically* the law is that while hunting migratory birds, your shotgun must be capable of holding at most 3 rounds. With the m4, strict adherence to this law would require plugging the mag to accept only 1 round. I don't expect the game warden to be familiar with ghosting, though... Happy hunting.

I found myself in need of a magazine plug for my m4 with Kip's FL mag (hunting migratory birds, mag must be limited to 2 rounds). I searched the internet, and even ordered one of those Butler Creek plugs, but it seems nothing out there is long enough (12 inches). In the end, I made my own, and thought I'd share the process in case there are others who are interested. Parts: 1) Brass tube, 13/32" (10.32mm) OD with 3/8" (9.53mm) ID by 12in. 2) Tree nut, metric thread, 9.60mm OD with 22.2mm diameter cap. 3) Wood dowel (screw type), 3/8" OD. [ATTACH=CONFIG]911[/ATTACH] Process: 1) Polish tube with metal polish for aesthetics. [ATTACH=CONFIG]912[/ATTACH] 2) Insert tree nut and hammer flush (interference fit). [ATTACH=CONFIG]913[/ATTACH] 3) Insert dowel and hammer in to tube to desired length. [ATTACH=CONFIG]914[/ATTACH] Finished product: [ATTACH=CONFIG]915[/ATTACH] To fit plug, simply remove the magazine cap and insert through hole in mag spring retention clip and reinstall magazine cap. The OD of the tree-nut is about 0.8mm smaller than the ID of the magazine tube. The pressure of the magazine cap centers the plug and keeps it snug in the tube (rattle-free). No tools required for installation/ removal. See following thread for pics of installation (can't seem to post more than 5 pix per thread.)

Thanks all for your feedback. I am leaning towards the LaRue, as I want to mount as low as possible. dprichard-I might be interested in one of your stock aimpoint mounts... will send PM.

I managed to obtain an aimpoint micro H1 at a good price, but it does not include a mount. I am wondering what those of you who run a micro on the m4 use for your base/ mount, and how you like it. It looks like there are a number of options out there: Larue LT661, American Defense T1-L, ARMS Inc. micro mount, the factory mount (where can I get one of these??), etc. I have Kip's mil-spec picatinny rail, so there should be no compatibility issues. Your thoughts are greatly appreciated!

I certainly used the magazine retaining spring clip in my carriercomp titanium full length tube, and it functions flawlessly. What gives you the impression that this is not correct?

Kip-I am flattered that you are interested in producing some of these, and would be truly honored if you saw fit to do so. Given the outstanding quality of your workmanship (already have the extended Ti tube and picatinny rail!), I am certain that your e-tool will be far superior, and I know I'd buy one. Stranger-I of course feel quite sheepish now that you tell me your solution: unloading the spring is certainly more elegant! The paint-pry tool sounds effective too... I was surprised that screwdrivers aren't commercially available with blades wider than 10mm or so. All- Thanks for your accolades and interest. I have really enjoyed visiting this forum for a while now, and have learned from you, so it's a pleasure to give back in some small way.

*Note: These forums don't allow me to post more than 2 images, and the ones I posted seemed not to work, so I have to link the images as URL's. Apologies! The flickr set is available here: http://www.flickr.com/photos/86193645@N00/sets/72157626271744939/ I've read on several threads here about the importance of keeping the recoil tube clean on the m4, and I decided it would be a good idea to clean mine. After removing the stock and the circlip, I soon realized that I would not be able to remove the recoil spring retaining nut without a specialized flathead screwdriver (16mm wide by 2mm thick blade!). I posted a thread awhile ago asking if anyone knew where to get such a specialized tool, but to no avail: http://www.benelliusa.com/forum/showthread.php?t=25736&highlight=recoil+tube Try as I might, I was unable to locate a screwdriver of the necessary dimensions (though maybe Benelli makes a special tool for the purpose?) So, I decided to make one, and chronicled the process in case it might be of use to others. 1) Draw out the plans for your tool. I used digital calipers to take exact measurements (all in mm) 2) Obtain a length of O-1 oil-hardening tool steel (ebay), 1 inch wide by 5/16 inch thick 3) You will need some basic tools: dremel with grinding/ cutting wheels, metal files, fint-tipped sharpie, etc 4) Carefully mark out your tool as per your design. Measure twice with calipers. 5) Begin making cuts with the dremel. Obviously you should wear eye protection. A respirator is a good idea too. 6) Finish cutting: 7) File down the driver blades and slightly bevel all edges. Keep tabs on exact dimensions with calipers. 8) Drill a hole (you'll see why...) and sand with 200, 400, 800 grit metal sandpaper to finish the operating surfaces of the tool. 9) Make sure the tool fits and operates exactly how it should at this point. We are going to heat treat it, after which it will become un-machineable. http://www.flickr.com/photos/86193645@N00/5575431057/ Notice the wire that has been installed so our tool can be plunged into the depths of a charcoal furnace. 10) Next we harden. You will need: charcoal barbecue igniter plus charcoal, tongs or pliers, a magnet, oil (I used motor oil). 11) Heat the tool to 1450 plus degrees F. This means cherry red to orange. At the critical temperature threshold where the carbon and iron shifts phases, the steel will become non-magnetic. Confirm this with the magnet and tongs. 12) Once the correct temperature has been reached, plunge the tool into the oil bath: http://www.flickr.com/photos/86193645@N00/5576018360/ The tool should now be about 62-64 RC hardness. Confirm this by running a metal file over its surface; the file should not bite. Hardened tool: http://www.flickr.com/photos/86193645@N00/5576018296/ 13) Finally, we temper the tool to make it tough and resilient (and not just hard). I tempered in the oven at 450 degrees F for one hour, to get a final Rc hardness of 58-60. http://www.flickr.com/photos/86193645@N00/5576018416/ You may also use this opportunity to bake some cornbread, should you see fit. Here is the finished tool: http://www.flickr.com/photos/86193645@N00/5576018232/ It may not be so pretty (the blue indicates that it will be very tough), but it is extremely functional (fits *perfectly* on the recoil spring retaining nut), hard, and strong. Also very small, so I can carry it on my keychain. Total cost was $10 for the O-1 steel stock. (granted, I already had the tools, charcoal, oil, etc.) EDIT: In the design of the tool, the 6.5mm tab at the bottom (really 6.1mm after filing) is designed to center the recoil spring nut. I *should* have beveled and filed the tip of this tab so it could be used as a rear sight adjustment screwdriver. The 5/16 in stock is just a tiny bit too large to fit in the slot of the adjustment screw without filing. I'd also consider machining a flathead blade on the side of the tool for the picatinny rail screws, so as to have a "Benelli multitool" on a keychain.

Does anyone have experience installing the GG&G model 1350 sling plate on an M4 with the C-stock attached? From what I've read, the installation process with the Benelli import stock requires removal of the buttplate to re-locate the mounting threads inside the stock (to compensate for the 1-2mm increase between receiver and stock interface caused by the plate). I am wondering if installation with the C-stock is even possible/ advisable, and if so, does one just screw it on behind the installed plate? Also, does anyone with this setup notice the gap between pistol grip and trigger guard thus created, and if so, is it annoying? Thanks!

I ordered a 5.5 mm wrench from amazon a few days ago.... cost was It's a Wiha 40001 Combination Wrench, Metric, 5.5-by- 100mm. Hopefully this will do the job! The Meprolights that I bought NIB are fully functional, but "factory imperfect" with a number of blemishes and scratches. The tritium seems a bit dim in comparison to the pistol Trijicon sights I have used. Also, the alignment notch on the ghost ring in the rear is not painted white as on the OEM unit, nor do the sights have white rings around the tritium inserts for daytime use. All in all, though, the MPL's are good night sights, and seem to be *almost* the only option (for $255, tooltechgunsight will apparently modify the OEM sights with Trijicon inserts... I'd be curious to hear if anyone has any experience with this mod...)

I keep seeing these go on ebay and gunbroker for 350+!

I have to say it... the Benelli C-Stock is really trick, and I am very happy I decided to get one. The middle position is also much more comfortable (for me anyway) than the very long stock stock (as it were...) Not so much a "heavy mod via trial error and research" but a really nice one IMHO nonetheless.

That makes sense... thanks for the clarification!

It seems plausible to me that one might be able to find some nice countersunk hex head screws in the right diameter and thread pitch. A quick google search for "countersunk hex screw" turns up a lot of results. Granted, I don't know offhand what pitch the taps in the M4 receiver use nor the diameter, but these things are easily measured. Of course, I would not be so surprised if the specs on this render commercially available hex head replacement screws "unobtanium" due to bizarre dimension choices on the part of Benelli (case and point: 5.5 mm front sight nut)...