benelliwerkes

Well, after studying the date code chart a little closer, I see that in the "B" series of date codes, Benelli did NOT use "BE" or "BG".........if we extrapolate to their same system of skipping "CE" and "CG"........this would mean that 2010 date code = CF and a 2011 date code = CH.........BINGO ! Italian word for "chamber" = camera......CAM is abbreviation; the chamber length is provided in millimeter lengths, 70 mm = 2-3/4" whereas the 76 mm = 3 " chamber . PSF = Polvere Senza Fumo = Smokeless Powder gun proof One * over the PSF = non magnum load proof test Two * over the PSF = Prova Superiore = superior proof for magnum load certification which was introduced for use in the 1960's. The cartridge proof load that is tested in the barrel is generally 20 - 30 % more powerful than the designated end-use of that particular barrel, which is essentially the margin of design safety.Current practice has proof pressures at 1020 and 1370 bars for normal and magnum proofs, respectively. The same designs that were proofed for 1200 have no problems passing 1370 bars. It is also interesting that some companies, notably Benelli, proof their guns in house at even higher pressure before submitting them to proof. PROOF MARKS. Proofing the barrel of a gun began as a means to insure its safety and integrity. Proof Houses were established by law in almost every country and it was required that weapons sold within the respective country, and for export, be able to withstand a prescribed load without damage. When this test was successful the weapon was stamped with a seal to acknowledge the test - which is called Proof Marks. These marks then tell us the country of origin of the weapon. Proof Marks change over time and therefore assist in dating arms. All guns offered for sale in all countries aligned with the CIP (Commission International Proofing), have to meet certain requirements. These standards stipulate that the strength of the barrel and action will ensure that the gun is safe for its intended purpose. All guns must carry proof marks to show that they have been tested and have passed the proof test, which basically means that the gun has fired a cartridge or cartridges that substantially exceed the maximum service pressure for which the gun is intended. Having fired an over-pressure ‘proof' load of around 20% - 30 % greater than its certified service pressure, the gun is stamped by the proof house. The “level” of Proof is dependant upon the caliber and chamber length of the gun, and whether it's intended for extra-heavy ‘magnum' loads such as some wildfowling cartridges; the testing and proof marks stamped on barrel and action will reflect this. Steel shot imposes a number of factors that affect the pressure produced by such loads. The need to launch the lighter pellets at elevated velocity to approach any kind of parity with lead loads is well documented. The fleur-de-lis (iris flower) icon proof designates approved for steel shot loads. [ATTACH=CONFIG]1240[/ATTACH]

Should have a CAM.76 = chamber length in millimeters = 3 " Your 18.3 is the barrel diameter in millimeters = 12 gauge PSF with the two stars above are Proof markings of testing for safety with magnum loads Your CH is probably incorrect......as it is a date of manufacturing code......which would mean a 2013 build date......see attached table for correct code and date. Busy right now to provide full scoop on Italian proof marks....but this example of a 20 gauge barrel should hold you over for now.[ATTACH=CONFIG]1236[/ATTACH] [ATTACH=CONFIG]1237[/ATTACH][ATTACH=CONFIG]1238[/ATTACH][ATTACH=CONFIG]1239[/ATTACH]

[ATTACH=CONFIG]1226[/ATTACH] Empirically, Benelli has determined the minimum threshold of kinetic energy required to cycle the bolt; the rest of the understanding is simple mathematics / physics. The attached may assist in understanding how adding weight / mass to the inertia platform may interfere with reliable cycling operation. The 20 gauge M1 bolt weighs 385 grams; a 2 shot magazine tube extension weighs 300 grams Plus 65 grams for the 2 cartridges and you have 365 grams of extra weight; almost the weight of the bolt. Third parties cite Benelli sources as stating that ~ 500 grams of added weight (1.1 pounds) begins to reduce reliable function. A 12 gauge 2 shot extenson and two 3" cartridges is just about 500 grams......again, just about the mass of the 12 gauge inertia bolt. So, the addition of the 2-shot extensions plus the cartridges do not exceed the bolt weight, but add a picatinny rail and a light etc......therein the problems of operation may begin to be experienced.

[ATTACH=CONFIG]1218[/ATTACH][ATTACH=CONFIG]1219[/ATTACH] When the inertia bolt mechanism is partially retarded for whatever reason previously mentioned it certainly would account for the intermittent problem......as you can see from the photos, the bolt latch requires the bolt to move completely throughout its range of cycling; if the bolt is not moving completely then there may be a malfunction in the carrier lifting action which you describe. I would expect that if there was some fundamental mechanical problem with the action, you would see a much higher rate of malfunctions.

Not quite sure what "jams" means as there are several distinct components to the cycling action of the Benelli mechanism.....extraction / ejection / feeding / etc...any of which not executed properly might result in a "jam". Assuming the gun is clean and all the parts are in good working order etc, then it may be helpful to remember that the M2's have an inertia driven bolt system which requires some relative motion of the gun about the stationary bolt; when the gun is so securely held or fixed, e.g. gun held in shooting mount or butt stock is against the ground, or if accessories are added to the gun adding weight, then the gun may not / will not cycle properly as the requirement for the gun to move relative to the bolt will have been defeated. So, actually holding the gun too tight, with the extra duck hunting clothing etc may be responsible for your experience of intermittent "jams" without an obvious cause. I would bet that if you fire a couple of boxes of shells one-handed the gun will not "jam".

It is important to know the fine differences between the factory screws and how they fit with the factory rails versus all the other aftermarket rail / screw combinations......they are small screws so unless you examine them closely they all seem to be the same and fit the same......they don't - which is the source of much of the misery discussed on this topic. Attached is one common screw comparison. The problems are at least 2 fold.....first, the incorrect thread pitch and second is a greater thread length on most after market screws , it's a small difference but there is a reasoned experience why the factory uses a specified length. Also, when installing the rail, OEM or otherwise, ALL the screws should be carefully placed and gently engaged with their threads before tightening them......kind of like the bolt tightening pattern when installing a car wheel.....begin to snug each one done about 1/2 turn or so, then do so with the others, until all of them have been sequentially secured. if you have a screwdriver torque wrench ~8.5" inch / lbs is a safe # for correct screws, +/- a dab of Loctite (blue or red dealers choice) [ATTACH=CONFIG]1217[/ATTACH][ATTACH=CONFIG]1216[/ATTACH][ATTACH=CONFIG]1215[/ATTACH][ATTACH=CONFIG]1214[/ATTACH]

Use #0000, that is 4-0, steel wool and a light oil with gentle linear strokes directed along the long axis of the receiver, avoid circular motions.

The last couple of photos to complete the explanation. Photos still out of sequence, even with a 50-50 chance ! [ATTACH=CONFIG]1209[/ATTACH][ATTACH=CONFIG]1208[/ATTACH]

The M1 magazine tube is removed just like the other M series tubes, heat gun and patience. For the M1 tubes that require removing the magazine tube to clean it, the magazine spring and follower....the removal part is easy. The circus begins when you attempt to keep the follower contained in the tube while you are re-installing the tube to the receiver. It lessen the drama with the installation step, if you are so inclined, you can fabricate a simple rod system to control all the parts together during the process. A few photos (which will exceed the 5 photos / post limit) will illustrate the process and the simple tool. I am not quite sure why the photos won't upload in the correct sequence, but you'll be able to figure it out. [ATTACH=CONFIG]1204[/ATTACH][ATTACH=CONFIG]1205[/ATTACH][ATTACH=CONFIG]1206[/ATTACH][ATTACH=CONFIG]1207[/ATTACH][ATTACH=CONFIG]1203[/ATTACH]

2+ Plenty to be thankful for in the great USofA.

I also use the silver anti-seize on the choke tube threads to make sure I can remove it unharmed. In the alternative, use a little more than finger snug tension on installation and apply a few drops of blue thread locker to resist the tendency for them to back out.

No one said it was easy ! The extractor has a hole in it, thru which passes the roll pin; the extractor spring is held in place by the back edge of the extractor internally. Remove the pin, the extractor and its spring will be liberated. The difficulty is that the pin has to be removed from top to bottom of the bolt head, as there is obviously insufficient clearance for the roll pin to exit the top of the bolt. A modified pin punch will be required as only ~ 30 % of the top of the roll pin circumference is available to make contact with any punch surface. The removal is facilitated by securing the bolt head in a padded vise to assure that all the force of the punch tip is transferred to the roll pin to initially "get it moving"; if you attempt it on a soft table top etc, the force will be absorbed by the platform the bolt is resting on. The factory probably has a special XYZ tip fitted to a hydraulic arbor press to spit that pin right out.

You might have to look closely for the lettering.[ATTACH=CONFIG]1170[/ATTACH]

This is how one of mine arrived from the factory. In Italian: D=dextro=right S= sinister = left [ATTACH=CONFIG]1166[/ATTACH]

Divide by 2.

You can use a Gear Sector rail / QD attachment. [ATTACH=CONFIG]1139[/ATTACH]

I keep this one configured plain Jane just for you Bello ! Enjoy. [ATTACH=CONFIG]1138[/ATTACH]

LOP is 9.25" with stock collapsed. LOP is 14.25" with stock extended. Extended butt stock adds 5" [ATTACH=CONFIG]1137[/ATTACH][ATTACH=CONFIG]1136[/ATTACH]

Precisely !

Some additional photos to illustrate the internal symmetry of the Safety-Trigger relationships. [ATTACH=CONFIG]1134[/ATTACH][ATTACH=CONFIG]1135[/ATTACH]

Still can't figure out how to upload the photos directly into the thread rather than thumbnails !

It doesn't matter what the safety position status is; the center of the safety is symmetrical allowing the detent plunger to fall into either detent and also to accommodate switching it about for left hand preference. Always remember to check the function of the safety in the trigger group while it is removed from the receiver and to re-cock the hammer and depress the bolt latch while re-installing the trigger group. Photo might help. Attempting to maintaining the red paint on the enlarged safety will probable not be durable as there is no circular recess for the paint to remain within; the close tolerance of the smooth surface aftermarket part will quickly remove it. [ATTACH=CONFIG]1133[/ATTACH]

This one is configured with most of the goodies on your Xmas list. [ATTACH=CONFIG]1131[/ATTACH][ATTACH=CONFIG]1132[/ATTACH][ATTACH=CONFIG]1130[/ATTACH]

I may have posted these photos before, but a simple fork tool to compress the safety spring is pretty handy. The diameter of the spring tunnel is not much larger than the diameter of the retaining roll pin which makes the tolerance fit for the tool really close !.....I am certain there is some special XYZ factory tool employed for this task. [ATTACH=CONFIG]1129[/ATTACH][ATTACH=CONFIG]1127[/ATTACH][ATTACH=CONFIG]1128[/ATTACH]

The stronger snap ring pliers are burdened by not allowing the tips to be positioned as close as needed to insert into the stout small snap ring; the smaller sized snap ring pliers allow the tips to be close but their diameters are small and almost too fragile to expand this particular ring. So, the snap ring tips were modified; each placed in a drill press and turned with a file, reducing the radius to match that of the snap ring engagement and it allowed the tips to be closely apposed for insertion into the ring. Only took a minute or so to do and prevents slipping of the tips and marring of the gun art. [ATTACH=CONFIG]1125[/ATTACH][ATTACH=CONFIG]1126[/ATTACH]