I think I'm the guy Kdash was referring to and I'd like to shed some light on the subject.
The 10 round magazines from S&W are pinned to only hold ten rounds. Problem is, without the load assist button, you can only easily load five rounds, for the other five, you have to find something to stick into the hole where the button would have gone, and load it that way, which can be a huge pain.
If you look here, I've detailed a solution and it has worked quite well. http://smith-wessonforum.com/smith-w...ml#post1247997
You can either do that or wait for Black Dog to make a shortened 10 round magazine, it's up to you. They have said they are working on one, but don't expect a working prototype for a month or so, so it's hard to say when they'll go on sale.
And just because everyone likes to see a train wreck, here's that video of me trying to load that blue follower mag. YouTube - Smith & Wesson M&P15-22 Clip For The State of NY
I would also like to add that they certainly could have added a load assist button and THEN pinned it to ten rounds. There's no reason why they couldn't have. Maybe S&W is trying to save money on load assist buttons? Also, don't bother calling them as they don't really have a solution.