You paid your money for a good gun ( the M-4 isn't cheap ) ...but why whine about the price of a $300 mag extension when you probably paid at least
$1,500 for the gun already ??
The last I heard Benelli could not provide the mag extensions on the guns because of some legal technicality ...but your dealer should be able to answer those questions - and the previous poster mentioned a code you have to comply with / so maybe that's the answer..
Why do you need a mag extension anyway ...isn't 5 enough ( or are the zombies out of control in your neighborhood ) ??
I bought a "25 round drum mag" - for my 1911 in .45 acp ...just for giggles ...but my 8 round wilson mags are what I really carry in the gun ...
If the mag extension is just for fun / go for it ... and everybody should buy what they want ... I just don't get it ...