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sonyman74

Enjoying my new Forend

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Lets see if I can dispel some myths here. The top rail is plenty strong to mount whatever optic you want. I've used EOTech 552's in the past on the M4 without any mounting issues. The problem is improper installation of the top rail to the receiver and the lack of thread locking compound to keep the screws tight. The receiver is quite thin where the top rail screws are mounted. Factory specification states that 12-14 inch pounds of torque be applied to the screws. This is very light. Two fingers on the screw driver will deliver that amount of torque easily.

What you want to do is to prep both the screws and the receiver holes with an acetone based cleaner. If the screws have thread locker on them from past installations, you will want to clean them off mechanically. I prefer a wire wheel brush on a Dremel to remove this material. Then you want to use blue Loctite #243 which is formulated for bonding dissimilar metals together. In this case, steel screws and an aluminum receiver. You don't want to go past the torque specs given because the screws will protrude into the receiver and prevent the barrel from being inserted. Or, if you had the barrel installed during this, the screws will be making contact with the barrel extension and you won't be able to remove the barrel. Over torquing the screws can also damage the aluminum receiver and strip the threads.

It was mentioned that Mesa Tactical had issues in the past. The reason for this was originally Mesa Tactical supplied the incorrect screws for the thread pitch. This has been corrected for a long time. Figure a Mesa Tactical shell carrier weighs around 6 ounces empty. I think some of them hold eight shells. At 2 ounces a piece, you're bolting on around 22 ounces.

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10 minutes ago, StrangerDanger said:

Lets see if I can dispel some myths here. The top rail is plenty strong to mount whatever optic you want. I've used EOTech 552's in the past on the M4 without any mounting issues

 

ROFL......... there are no MOUNTING ISSUES.... that goes without saying, the ISSUE is keeping an Eotech (or something even larger) MOUNTED over xxxx# 1000s of shots fired.

1. the M4 / M2 receiver is ALUMINUM

2. Mass / inertia SHEERING FORCED imparted by good old Newtonian LAW will SHEER the screws, and if the screws manage to NOT SHEER, the threads will STRIP,........PERIOD

 

and NONE OF THIS has a single darn thing to do with loctite and or proper torque applied to those screws. 

 

You said "Lets see if I can dispel some myths here"

the only MYTH on this thread are the countless people that think laws of Newton / Physics DONT APPLY to a HUGE MASS sitting on a rail screwed into an ALUMINUM RECEIVER

Edited by kenw111
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11 minutes ago, StrangerDanger said:

tenor.gif?itemid=3681010

 

Is that what passes for an intelligent rebuttal here in the "Land of OZ"?

 

tell it to this guy (below) that mounted a large-mass (same as an Eotech) Aimpoint on his M4

sheered off

Im a gunsmith and seen it happen twice on Benellis.   So, Marsha,.... facts are facts.  The laws of Newton / Physics STILL APPLY

 

screenshot_1469.jpg

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You wouldn't change your position no matter what amount of evidence was given, so why bother? Telling you about the M4s' with 10,000 rounds of high base through them with EOTech 552's would be a waste of time. Or the 100+ Benelli M4's that have come thru my shop for work in various configurations. So why argue?

 

You can do as you like.

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37 minutes ago, StrangerDanger said:

You wouldn't change your position no matter what amount of evidence was given, so why bother? Telling you about the M4s' with 10,000 rounds of high base through them with EOTech 552's would be a waste of time. Or the 100+ Benelli M4's that have come thru my shop for work in various configurations. So why argue?

 

You can do as you like.

you:

1. NO EVIDENCE

2. your own anecdotal account.

 

me:

1. one example posted above...yet another one below... ( i can post 2 more if you wish)

2. laws of Newton / Physics

3. Seen it happen twice myself.

 

screenshot_1471.jpg

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48 minutes ago, StrangerDanger said:

 Or the 100+ Benelli M4's that have come thru my shop for work in various configurations. So why argue?

 

Please report back:

1. how many of those people unintelligently mounted an Eotech or larger on their Benelli

2. Of those that DID,...... how many rounds down the barrel

 

otherwise its called a hearsay fallacy.

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The EOTech's were more popular 15 years ago on the Benelli. So I don't see many of them anymore. There are better, smaller options available now. The most popular ones are the Triicon RMR and Aimpoint T1. The Trijicon SRO's are starting to pick up. Sometimes we see an Aimpoint M4 or M5 come thru.

One I have had a verified 10,000 rounds of buckshot and slugs thru it. Zero issues with it. We would have a lot more complaints here on this forum and others if it was an issue. Picking a couple complaints out of the internet is a fallacy since we do not know if it was installed correctly. Or if it was one of the Mesa Tactical mounts with the incorrect screws. The main complaint would be with the heavy shell carriers like Mesa Tactical which weigh significantly more than an EOTech.

I don't recommend these heavier optics or shell carriers; but the platform will certainly handle them when installed correctly.

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52 minutes ago, kenw111 said:

 

ROFL......... there are no MOUNTING ISSUES.... that goes without saying, the ISSUE is keeping an Eotech (or something even larger) MOUNTED over xxxx# 1000s of shots fired.

1. the M4 / M2 receiver is ALUMINUM

2. Mass / inertia SHEERING FORCED imparted by good old Newtonian LAW will SHEER the screws, and if the screws manage to NOT SHEER, the threads will STRIP,........PERIOD

 

and NONE OF THIS has a single darn thing to do with loctite and or proper torque applied to those screws. 

 

You said "Lets see if I can dispel some myths here"

the only MYTH on this thread are the countless people that think laws of Newton / Physics DONT APPLY to a HUGE MASS sitting on a rail screwed into an ALUMINUM RECEIVER

As long as you think that you know what you're speaking about, you might as well learn the difference between SHEER and SHEAR.

The word that you're using to describe the SHEARING FORCE on the pic rail has no application for what you are talking about. SHEER and SHEER-ING is not even a word in this context.

Unless you're talking about ladie's stockings.

 

 

Edited by Evolution

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5 minutes ago, Evolution said:

As long as you think that you know what you're speaking about, you might as well learn the difference between SHEER and SHEAR.

The word that you're using to describe the SHEARING FORCE on the pic rail has no application for what you are talking about. And SHEER-ING is not even a word.

 

 

Shhhhh.!  Dont get him mad, he dont like grammar nazi's 😁

(I've never seen anyone with a negative reputation before! 🤣🤣)

Edited by Jolly Roger
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5 minutes ago, Evolution said:

As long as you think that you know what you're speaking about, you might as well learn the difference between SHEER and SHEAR.

The word that you're using to describe the SHEARING FORCE on the pic rail has no application for what you are talking about. SHEER and SHEER-ING is not even a word in this context.

Unless you're talking about ladie's stockings.

 

Yes yes, my typo. ...   indeed

 

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Just now, Jolly Roger said:

Shhhhh.!  Dont get him mad, he dont like grammar nazi's 😁

(I've never seen anyone with a negative reputation before! 🤣🤣)

 

Just now, Jolly Roger said:

Shhhhh.!  Dont get him mad, he dont like grammar nazi's 😁

(I've never seen anyone with a negative reputation before! 🤣🤣)

It was inevitable from his very first post on this forum railing about Benelli for some ridiculous crap.

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1 hour ago, StrangerDanger said:

I just assumed Amsdorf 'it's smokin' like a chimney,' got a new account finally.

Yeah, it's been years since we have had a forum DQ, now we've got one. We're so blessed!

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We'll see his Fisher Price painted M4's up for sale here under a different user name in about a month.......hope he moves to the AR forums..🤨

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21 hours ago, 808M4 said:

Didn't Carrier Comp previously make a replacement picatinny rail, because the OEM one is known to be crap?

Kip did produce a few rails at one point and they were on par with everything else me makes. The Benelli rail is known not to play well with the Larue mount (the Larue mount gouges the Benelli rail from what I gather, I've never tried it myself) although I've had zero issues with a A.R.M.S. #31 mount.

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8 minutes ago, shootingsight said:

For some reason, it locked me out as I was editing, so here is a repost with my thought in reason #1 completed.

 

AAAHAHAHAHAHA! I've been making triggers for 15 years now, and have been active on dozens of forums, corresponding to the various platforms I was working on.  It's been quite a few years since the name Amsdorf was mentioned.  Thanks for a good laugh to start the day.  What a clown.

As to this discussion, the term 'shear' is based on the notion of two parallel planes moving relative to each other.  For the system to fail in true shear, with the shear planes touching, you would expect the threads of the mounting screws to still be in the receiver, and the top of the screw still in the rail.  However this is not what has been reported as the failure mode.  Instead, we are talking about threads stripped out of the receiver and receiver holes elongated.  To get this failure, you need upwards/bending load on the threads, even though recoil load is backwards.

 

I can think of two ways to make this happen:

1. If the screws are loose.  The resistance of the rail sliding on the receiver is the friction between the two.  Friction is of course a function of normal force.  So the function of the screws is not to prevent slipping of the rail versus the receiver, but to provide the normal force so the receiver and rail do not slide relative to one another.  Loose screws means the normal force is reduced, and sliding will start, creating a bending force on the screws, which concentrates force on the top edge of the threaded hole.

2. If the screws were overtightened in the first place, causing the onset of failure in the aluminum threads prior to recoil.

Both of these failure modes would be accelerated by a heavier optic.

 

Net I think this sort of failure has several factors as its root cause: a heavy optic, plus improper installation.  One or the other alone might not cause it.

 

Me personally, after reading this, I'd add loctite on the surface between the rail and the receiver before tightening the screws.  Loctite is designed to increase the shear strength between materials, usually between a bolt and a tapped hole, but it should also work between a rail and the receiver.

 

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Your explanation of what must occur for damage to occur mirrors my experience. Improper installation is the main source of failure for damn near anything in any field. The only way you’re damaging the rail is by over torquing the screws and stripping the threads or if the screws come loose and the rail starts moving around under recoil. The factory screws have nice lock washers that help bite into the anodized aluminum rail since the factory doesn’t use locktite there. 

Locktite generally weeps beneath the rail during an install and will provide some adhesive bonding the rail to the receiver. I usually have to hit the rail with a light plastic tipped no mar hammer to break it free. 

Had this been a real issue, Benelli would have extended the rail so that it butted up to the rear sight housing to minimize rail movement. 

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Counting on wicking might be touchy.  The shear strength of loctite is a function of square inches of contact area.  It does not have to be thick, indeed, for most adhesives, thinner is better, but you want big contact area.  So I'd be generous in the application.  Typically, I use green loctite, which is exactly designed to wick into cracks, and it is billed as being designed for application to screws after assembly, so the capillary action pulls it in.  I don't trust this and generally apply it before assembly.  Just beware that it comes in several varieties with differing setup speeds.  For some, you only have a few minutes to complete assembly.  Green is stronger than blue, but isn't permanent.  With a few seconds from a blowtorch, it will loosen up.

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You’re probably right about applying the green wicking Loctite to the base before seating the rail. Torque the screws and wipe up any excess. I might add that going forward since it doesn’t hurt anything. 
 

Scalarworks realized that the forces encountered weren’t that severe. They only use 4 of the 5 holes for the Sync rail. Granted these are smaller optics. But if it were even somewhat near the fence on strength, I would imagine they would have used all available holes and maybe butted the rear of the rail up against the rear sight housing. 

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LOL.  You might be giving too much credit to the engineering budget of companies.  I spent my career in a Fortune 100 company doing R&D, and we did what you think: if there is a doubt as to strength, you get 10 units (or 100), and you smack them with a drop test or multiple recoils until they break .... because you can afford that.  Smaller companies will take one, try it out and if it does not break right away, they call it good.  Dunno how big Scalarworks is or what they did, but I'd question how many receivers they were willing to destroy to confirm their design.

 

That said, your thought about butting the rail up against something makes a lot of sense, and is a freebie.

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I hate even coming close to agreeing with Mr. Horse Stroker, but I think by putting anything other than a RMR up there you're flirting with danger.

Ive done my fair share of drilling and taping 6061 T6 aluminum and even though its Rockwell is better than what most would believe, its tensile strength sucks. 

I have Permatex Ultra-Black between the receiver and the Scalarworks mount AND between the RMR to the Scalarworks. Wiped clean with a few Q-tips afterwards and you cant tell its even there. 

 

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I think it would be more of an issue if the limits were being approached. There are a whole bunch of 8 round shell carriers from Mesa out there with optics bolted to the top. You're looking at 24-30 ounces of weight depending on configuration being bolted on. We'd see a lot more examples of the screws being stripped out if it were the case far beyond what our resident autistic could find over several decades of tech questions.

I wouldn't recommend adding all that weight anyway since the firearm is much more functional in a lightweight build out. Keeping extra rounds on your body is better than slapped on the side of your firearm too. Cherry picking one round at a time from a side saddle is significantly slower than say a California Competition speed loader. If the concept is to keep rounds with the gun for a bump in the night situation; you'd be served better by putting one of those Blackhawk bandoliers that carry like 55 rounds with the shotgun.

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