Interesting that you used devcon. We use it to fill dents on aircraft leading edges. If it can stand up to 500+ knot airspeeds and pressure/temperature ranges we deal with it should work a treat on the low stress application seen here.
My M4 would have occasional problems as well when it was really new. I solved them by liberal application of lube and good old break in. After a few hundred rounds it runs great, will blast out all 8 rounds as fast as I pull the trigger, with cheap old wally world birdshot.
Switching out the stock requires no tools and takes about 5 minutes, tops. You just have to pull the bolt handle out, pop the trigger group out, and unscrew the stock by hand. Unless you have a great relationship with your local shop, why not save some bucks and get it online for less?
There are about 200,000 Marines with Eotechs on their (Benelli) M-4s. It seems to work well enough for them, and if you search you'll find plenty of pictures. That said I have a couple of EOs and wanted something smaller so I got a Burris fastfire (Dr. Optics clone) for mine. Sorry, don't have a pic with it mounted.
Actually a local gun shop here has them for $30 each! I picked up several, $10 hicap mags for my XD just can't be beat, and the little hard case is just a bonus.
Thanks for the suggestions guys. I found a B&T one with two rails that is $50, when the single is $75 from the same place, that's weird. I like Mesa's products but couldn't find any rails for Benellis, only the 870. Maybe it would fit, I'm not sure?
I'm going to mount a TLR-1 light on my M4, but I need a short piece of rail to mount it on. What's the best solution for a small/simple clamp on picatinny rail that would clamp onto the magazine tube? I'm not really a big fan of the Surefire forend and don't need all that rail real estate.