Extended Mags...ALWAYS use a clamp!

[VARifleman]

First of all...I'd like to mention that I've already talked to Nordic and they are taking care of me on this issue. Apparently I got a first generation tube, and those had some issues, as you will see.

Today I took my shotgun out to pattern some buckshot and birdshot (may want to shoot skeet with it) and compare slugs (Brenneke KOs won over Remington Sluggers). Didn't have any issues on the line except for a target carrier that gave me fits and didn't want to come back but 30 percent of the time.

Then...I start to pack my gun up, and what the heck? The tube has moved forward about 3/16". The gun worked, but I was a little suspicious of this.



Took it apart when I got home and...









The mag tube broke at the threads that screwed into the mag nut. Had I not had a clamp on it, it would have shot itself down the range, which would have been embarrassing, and been a waste of my range time, fuel, and targets. Had I not had a clamp and someone broke into my apartment, that tube could have launched on the first shot and I'd have been left with an 8 lb club and my pistol.

Lessons learned at the range today...

ALWAYS use a mag tube clamp
ALWAYS have a backup gun
#1 Buck patterns A LOT bigger that 00
I could shoot skeet with this if I wanted to without even changing the choke, maybe trap
KOs > Sluggers for MY shotgun
2 3/4" Magnum #1 buck shells feel the same as 00 buck, but get more than twice the pellets
I need to work on slug shooting more.

Time to do some chores now.

 

[Fred Fuller]

How many of us here have said that, how many times?

Some people insist on taking chances. Thankfully for them, the majority of the time they get away with it. The metal at the end of a magazine tube where that extension screws on is awful thin, already deformed due to threads, and that extension is a nice lever magnifying any thrust applied to it, right to the gun's most vulnerable area.

But naaaaah, I don't need no clamp.

lpl

 

[VARifleman]

I know many including yourself have, but I figure some pictures of it actually happening, especially when a moment wasn't applied on the gun, it just broke during recoil, may get some of the naysayers to wake up and actually use a clamp.

 

[19-3Ben]

Had I not had a clamp and someone broke into my apartment, that tube could have launched on the first shot and I'd have been left with an 8 lb club and my pistol.

Yeah, but how many guys can shoot the end of their mag at a bad guy?

 

[357wheelgunner]

I saw a guy drop his shotgun, the joint where the unsupported extension screws to the tube hit the edge of the range table. The tube snapped in half and the spring shot out into the range.

I always use a clamp.

 

[MAX100]

Nordic tube exteensions are made of Aluminum. Had it been made of high quality steel and been a one piece tube that wouldn't have happened.

Aluminum and a two piece tube ext is a bad combo.


I never use a clamp and ONLY use one piece steel tube extensions on my shorter bbl shotguns.


GC

 

[VARifleman]

MAX...steel is not necessarily stronger than aluminum, you can build it either way and get a good result, but steel is much heavier, which is a disadvantage for a fighting shotgun, especially when it's already going to be muzzle heavy.

 

[MAX100]

I disagree one piece steel tubes are much stronger and not that much heavier.

If you are worried about a little extra weight lose the mag clamp.

Many mount a flashlight near the muzzle and the weight don't bother them.

GC

 

[green country shooter]

The clamp that came with the extended magazine for my Benelli M2 will not stay in place, since there is no groove on the extended tube for it to grip. I'm reluctant to tighten it down in serious way, since I have bent mag tubes on shotguns before. Anyone have a solution?

 

[MAX100]

The clamp that came with the extended magazine for my Benelli M2 will not stay in place, since there is no groove on the extended tube for it to grip. I'm reluctant to tighten it down in serious way, since I have bent mag tubes on shotguns before. Anyone have a solution?

I have heard of some coating the inside of the clamp with a spray on rubber coating sold at Auto Parts stores that works well.


GC

 

[Fred Fuller]

Max,

One more time- the issue is not the strength, brand name or construction of the magazine extension.

The issue is the potential for damage to the end of the MAGAZINE TUBE where the extension screws on.

Not saying you or anyone gotta use a clamp. Don't personally care whether you do or don't. Your business, your shotgun to damage if you have a bit of bad luck along the way. Hope it doesn't happen to you, chances are it won't, but if Murphy ever decides to pay you a visit, a clamp is cheap insurance.

lpl

 

[MAX100]

Remington is the only one, I believe, that uses a mag clamp on their shotguns. Mag clamps provide very little protection. As the post above most walk or loosen under recoil. They only help with vertical impacts and don't provide much protection with side impacts.

They are needed with longer tube extensions past 3 rounds.


GC

 

[357wheelgunner]

Nordic tube exteensions are made of Aluminum. Had it been made of high quality steel and been a one piece tube that wouldn't have happened.

You guys are missing that it wasn't the extension that broke, it was the magazine itself. Steel or aluminum doesn't matter.

Remington is the only one, I believe, that uses a mag clamp on their shotguns. Mag clamps provide very little protection. As the post above most walk or loosen under recoil. They only help with vertical impacts and don't provide much protection with side impacts.

That's not true at all. The clamp, when placed near the end of the tube, resists movement in all directions. There is danger in even firing the gun with a fully loaded magazine, the weight of the shells inside the tube creates a lot of inertia under recoil, with the threaded area connecting the magazine extension to the magazine being the fulcrum. With the area already weakened by threads, it has, can, and will cause a break regardless of what the extension is made of. This is just from the load created by firing the shotgun with weight inside the extension, and not even going into how fragile it is if the gun is dropped and pressure put on the end of the extension.

It's common sense.

The only extension I wouldn't worry about bracing is the tiny 1 round extensions that Wilson puts on their 14" 870s, it's hardly longer than the end cap itself.

 

[kingjoey]

A big difference (and why I wouldn't use aluminum for a mag tube) is that aluminum has no elasticity, vibration and flexing eventually causes failure. Having an aluminum tube of approximately the same dimensions as the steel equivalent is going to be problematic. Aluminum is stronger than steel by weight, not cross-section, so a similar dimensioned part out of aluminum is going to be substantially weaker than its steel counterpart. A steel mag tube with a decent wall thickness should work fine with or without a clamp. The clamp helps keep the extension from walking off though which is a plus.

The tube in the pic is horrendously under-spec for something made from aluminum, the metal fatigued and snapped. This occured because the wall ahead of it is much thicker and the receiver it is screwed into is much thicker. This leaves the threads as the weak point and the flexing that occurs during firing is going to cause the most fatigue at the thinnest spot.....viola!

 

[VARifleman]

Ok...

Let's go through your post king joey,

Aluminum has 3 times the elasticity of steel. It's ductility leaves something to be desired, but firearms designs should all be well before yielding.

Fatigue had ZERO to do with the failure at hand. You don't reach fatigue failure of aluminum in 30 repetitions, not even 100 or 1000.

Aluminum can be stronger by cross section, it depends on the alloy and hardening due to forging or heat treating.

A steel part of this size may or may not have broken this way, but without a clamp, you are only as strong as those threads on the mag tube, which were not designed to take all of the recoil energy of 4 shells, much less 8. It certainly is not good enough to sustain any kind of hits to the tube due to moment capability due to length.

 

[xx7grant7x]

Yeah, but how many guys can shoot the end of their mag at a bad guy?

LMAO

 

[kingjoey]

Ok...

Let's go through your post king joey,

Aluminum has 3 times the elasticity of steel. It's ductility leaves something to be desired, but firearms designs should all be well before yielding.

It is more easily bendable, but it stretches rather than flexes. This results in cracking and weakened grain. It doesn't "bounce back".

Fatigue had ZERO to do with the failure at hand. You don't reach fatigue failure of aluminum in 30 repetitions, not even 100 or 1000.

You can reach a failure point from fatigue with ONE repetition depending on the material and the amplitude of the movement. In a setup like the magtube there is going to be a lot of rigidity so the repetitions are going to pull at the grain of the material rather than bending it. The part failed at its thinnest point which was also the flex point in this case, pretty typical of aluminum failure. The areas ahead and behind the failure point are reinforced.

Aluminum can be stronger by cross section, it depends on the alloy and hardening due to forging or heat treating.

Certain alloys have properties similar to steel, but with trade-offs. Somehow I'm doubting that this magtube was made from anything better than 6063/recycled beer cans.

A steel part of this size may or may not have broken this way, but without a clamp, you are only as strong as those threads on the mag tube, which were not designed to take all of the recoil energy of 4 shells, much less 8. It certainly is not good enough to sustain any kind of hits to the tube due to moment capability due to length.

There is also a SPRING in between those 8 shells and the end of the tube, the recoil impulse is dampened. The threads will handle the force as long as they are die-cut instead of swaged. The only mag tube problems I've seen is on cheap tubes that had loosely cut (H3+) threads, YMMV. The only concern I would have with a long mag tube is the possibility of bending the extension/tube from something hitting it, not stretching/tearing it from recoil.

 

[Gordon]

Still I reccomended the Remington factory tube and clamp. This requires another mount on the tube for a light but you can put it real far back and then you don't need a tape switch for the TRL1. BTW, on 3 gun match custom 1100s I had in the 80's they were shot alot and the Choate 8 shot mag never failed with the choate clamp. Sometimes the high zoot gear is not the schizzle in the real world.
I totally take exception that you do not need a clamp on an extended mag tube, with the exception of the short Wilson one which does seem stout enough.Seen too many launch with out one , leaving you with a single shot!

 

[VARifleman]

The tape switch is far enough out there, I definitely would not be happy with moving my left hand way out to the end of the handguard to switch the light on.

As for choate, I was going to get them, but I have a problem with them using a welded tube.

Kingjoey, when something is loaded and then it stays there instead of bouncing back after unloading, that's plastic deformation, which is beyond the point that one should have a design for in a firearm.

And no, you can't reach fatigue in 1 loading because its definition requires cyclical loading. If it breaks in 1 loading, that's just reaching the ultimate failure point.

And when fully loaded that spring has about 1 inch of travel in it. It's also loaded at twice the factory level for 8 rounds or else the next shell wouldn't chamber. Bump that to 12 and you're at 3 times the factory level, and even at factory levels they have a spring retainer that holds the load, not the threads on the mag tube.

 

[kingjoey]

With 12 rounds you'd need a clamp just to keep the tube from bowing BTW, 1 repitition is a cycle. Some parts will fail on the first cycle some will last millions of cycles, depends on the material, design, and amplitude. I'm not opposed to clamps, I'm just saying they aren't a cure-all or completely necessary. Most clamps aren't precisely fitted or tight enough to keep the recoil impulse from working on the threads. A sheetmetal clamp is going to have some take-up/backlash before resisting the movement of the tube. The main advantage to the clamp is triangulation and weight support. On a shotgun you also have the mag tube supporting some of the barrel weight and force. Adding a clamp helps brace the barrel and tube together, sort of like the lattice beams in a truss, it increases rigidity. Tube flex from weight would likely be more of a problem than the shotgun shells resisting the recoil impulse of the gun.

 

[VARifleman]

Things can fail on the first loading, but that doesn't make it fatigue. It simply makes it failure. Fatigue occurs at lower than ultimate strength and failure is due to hardening of the material through the work put on it. It is a much more brittle failure than the failure on the first cycle. The failure of my tube was not fatigue at all, and that's what I've been trying to point out to you over the past several posts. Hell, you can see from the second picture that it isn't a fatigue failure as the metal is stretched and pulled apart in a ductile failure with 45 degree cleavage. Also, this clamp is machined, not sheet metal. It's a Nordic setup after all.

 

[Zach S]

I have heard of some coating the inside of the clamp with a spray on rubber coating sold at Auto Parts stores that works well.

I would imagine RTV would work well too. I've used it similar situations, cant recall any specifics though. It even comes in tactical black

 

[green country shooter]

What is RTV? I'll check at the parts store for the spray on rubber coating. Do you have a brand name?

 

[Bob Hostetter]

Alum is not the best choice for a shotgun magazine extension tube. Failures of alum tubes are fairly common in high usage shotguns. We only use steel tubes. What brand you use is up to you, we use Daves Metal Works steel tubes, but steel is the only way to go.

The difference in weight is too small to be of any consideration.

 

[4thPointOfContact]

What is RTV? I'll check at the parts store for the spray on rubber coating. Do you have a brand name?

Room Temperature Vulcanizing sealant