Finally got a M4 after wanting one for some time, but I'm finding the length of pull to be a little long. Does anyone know if the M4 with the NP3 coating (model 11718 I believe) is capable of accepting the factory collapsible stock? I haven't taken the factory stock off to see. Also, are the only two options for a shorter stock the collapsible and the urbino stock? I have searched google and these two are the two that keep coming up.

Finally, which stock is recommended? I like the collapsible in terms of how it looks (cool factor as this is just going to be a range toy and possibly home defense) but I have a concern about it just being attached via the action spring tube and possibly bending. And how durable is the urbino stock? I read one review about the plastic adaptor for the butt pad breaking after being hit on the ground. It's not like I would be using it to beat down door or anything, but if someone dropped it or tripped and fell with it, I don't want the stock or tube bending/breaking. Sorry for all the questions in one post, any advice or insight is welcome.

Which stock do you have?  The pistol grip stock or field stock?  

The factory collapsible stock is plenty sturdy, that's what I have on mine and I have zero concerns about it's ruggedness.  The stocks (any of them) take about ten seconds to remove, if you want to pull yours off and verify that you have the notches necessary for the collapsible on your spring tube.

I may be wrong but I recall the field stock being a shorter LOP than the PG stock.

The collapsible stock has pro and cons.  Pros:  It's very solid, well built, doesn't move around.  Easier to store.  Weighs about the same as the PG stock.  
Cons:  LOP fully extended is about the same as the PG stock. The mid position is about 1.5-2 inches shorter but it is hard to use the iron sights because your cheek weld is higher.  Also your cheek gets more beat up under recoil using that position.  Using the mid position also shifts the center of gravity forward making it more nose heavy.


Yours should accept the collapsible stock no problem; you just need to verify it has the notches for the mid position on the recoil tube.  You can check easily, the stock spins off.

My understanding is that the Mesa stock has a shorter LOP while maintaining the same drop so it is easier to get a cheek weld with irons.

I have the pistol grip stock. The only shotgun I have ever owned that I didn't find the factory stock to feel a little long is my SBEII (Super Black Eagle 2). I have a fairly thick chest, arms, and shoulders from lifting weights and I have had to swap the stocks on my other shotguns (all field stocks) for ones that are and inch to inch and a half shorter than factory. Otherwise I have trouble standing squared off to what I'm shooting and having a comfortable grip on the fore end and grip.

The collapsible stock in the mid position will probably work very well for you.  It's designed for use while us normal sized folks are wearing body armor.