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Tight Magpul MOE Forend question (French pronunciation) and more...

Sheepdoggit

Sheepdoggit

.22LR
As far as the Fr.... nevermind ;)

I just bought a Mossberg 590A1 because I want this gun to be as sick as it can be (and yes, it will sport an M7 eventually for FU factor, ;) (and yes, I am an adult child anymore).

That said, I received my MOE forend last night, mounted it, and now the incredibly slick action is gone. This thing is as tight as a tick.

In other words the polymer tube inside of the forend seems to be hugging the steel magtube way too much (it is steel and not aluminum, right?). I saw someone on Amazon say they had this problem and it ended up wearing the finish off their mag tube.

Now I don't really care about normal wear, I actually like the Boba Fett look, but I don't like to add them unnecessary. Have others had this problem? I assume sandpaper would work, but then am I going to risk the forend not conforming uniformly to the point where it's noticeable?

The other thing is more of an observation. I have an MOE handguard on an AR that I like just fine, but when I compare this to the factory cob offering, I like the latter much better. The two reasons for the MOE forend in my opinion is supposed to be the mounting capabilities and the ergos (especially the hand stop). To me, the cob forend has 2 or 3 times the traction, and that more than makes up for that in my opinion. That stock forend is ribbed for her pleasure, and if I could just add a light to the stock configuration I would. I also know I can stipple or use skateboard tape, but I'm exploring all options.

Now I guess that leads me to my last two inquiries. One, has anyone ever modified their cob to attack a rail?

And two, do people have another mounting option that they highly recommend? Doesn't the military have lights on their guns? What do they do?

Thanks in advance.
 
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I like the Elzetta light mount on my Winchester 1300. It doesn't move around under recoil like the ATI mounts do.
 
I would rather hone out the plastic cob with a drill and hone, than suffer excess wear and drag on the tube. (BTW,everyone calls this stuff "polymer" in the gun world because it sounds so technical, but polymers are only a component of most plastics.)

These plastic things typically shrink a little after molding, but just how much and where and how they shrink is a very complicated matter. It's tough to predict, so parts usually get prototyped and the tooling or process gets tweaked until things fit correctly.

Either this wasn't allowed for in the die set, or somehow the process has changed since prototyping.

A typical change would be to reduce cycle time of the molding, and this is sometimes results in parts that look OK but are a few thousandths or a few hundredths "off" here and there.
 
That's great feedback CaddmannQ. Thank you. Maybe I'll send it back and try another and stipple or skateboard tape it. I do kind of like the idea of modifying the cob though.
 
I guess griptape is OK if you wear gloves, but the stuff I buy would shred your bare hands.
Hell, it shreds my leather gloves when I skate.

ALSO, I forgot to mention mold release compound.

Some plastics require a release compound, like a wax, so they don't stick to the molds or dies.

If you don't remove this it can cause dust attraction and unwanted friction.
Maybe try just washing the bore out with some WD-40 or paint thinner on a rag, and see if the result seems more slippery.
 
Did you install the correct insert in the front of the MOE forend? There are two included, one for a standard profile barrel, one for the heavy barrel on a 590A1, if you installed the one meant for a standard barrel it would likely bind on the heavy barrel.
 
swsabre said:
Did you install the correct insert in the front of the MOE forend? There are two included, one for a standard profile barrel, one for the heavy barrel on a 590A1, if you installed the one meant for a standard barrel it would likely bind on the heavy barrel.
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Yes, I checked the number to make sure it was right. Thanks though.
 
I heard back from Magpul today, and this is what they had to say about it:

"Thank you for contacting us. The hand guard mounts to the action bar assembly which goes around the mag tube so that is not the issue. what usually causes this is the out side diameter of shotgun barrels varies a lot and if yours is larger the shim can rub on the barrel a little. if you rack the slide several times and then remove the barrel you will see some rub marks on the anti rotation shim with some sand paper remove a little material from where you see the rub marks and this should fit the issue."
 
Something else that had been recommended to me at one time is to use a dowel rod wrapped with sand paper and sand across the barrel channel. It was a rep from Hogue who suggested this with regard to forends that are too tight. She said a few thousandths of an inch can cause it to be too tight but it's easy to remove if you're willing to try it.

@CaddmannQ Thats interesting info about the mold process and how tolerances can be off. I think we often consider this stuff to be within spec as if it's a precise science.
 
Mine was like that. All I could do is modify the fore end a bit.

Everyone complains about rattle snake Mossbergs, so I think it's made very close to tolerance for a tight fit.

Sent from my SM-G935T using Tapatalk
 
I have 2 Magpul for wends and haven't experienced the tightness issue for either, but I also have them on 590s and not an A1. I did have that problem with an ATI forend. It was so stiff that I replaced with a Magpul.
 
Rossignol said:
. . .@CaddmannQ Thats interesting info about the mold process and how tolerances can be off. I think we often consider this stuff to be within spec as if it's a precise science.
Click to expand...

Any time you cast or mold parts they typically shrink, except for a few things like ice. You also need to taper things so the mold comes off.

There is really no magic formula. There are guidelines and rules of thumb, but its mostly a matter of experience in design.

Such things must be prototyped and checked and tweaked to be precise.
 
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Mine was tight a couple of weeks ago also. Lube the hell out of the action bars and the outside of the magazine tube. I followed up the next day with 100 rounds and she is smooth again.
Don't worry, it will loosen up, just keep working the action.
 
kalison said:
Mine was like that. All I could do is modify the fore end a bit.

Everyone complains about rattle snake Mossbergs, so I think it's made very close to tolerance for a tight fit.

Sent from my SM-G935T using Tapatalk
Click to expand...

It's funny, but I had an expensive BPS that rattled just as much. I figure the shotgun if used is going to be loud anyway between racking and firing. ;)
 
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