The moe stock does not have the friction lock on it (which helps with keeping the stock solid and not wobbly) and the ctr does. The moe handguards are just a drop in pair for a carbine length gas system, which translates to a seven inch length (just making sure in case you didn't know). They don't offer them in any other length as far as I know. I hope that helps you out Rob. Let us know how the Zombie killer works out for you.