I need an accessory rail to fit onto the standard M&P15 Sport hand guard so that I can attach the Magpul AFG2 - Angled Fore Grip. The first one I bought didn't line up correctly. Can someone please recommend the correct rail?

Also, I'd like to replace my stock front iron sight with the Magpul MBUS Pro but I'm not sure what part I need to correctly attach it to the barrel. Can someone recommend the correct mount?

You don't just "replace the front sight" on the Sport. That front sight is also the gas block. You will either need to get a gas block with a rail on it, or add a free float rail handguard, which requires you to either shave the existing sight / gas block down so that it will fit under the railed handguard, or replace it with a micro gas system.

As far as the rail, you would need one that is made for tapered handguards.

My advice would be to forget the angled foregrip and sight and shoot the rifle as is. Spend money on ammo. After you have shot it for a while, you will know more of what you want out of the rifle, and how to change it up.

An extension of what cypher has suggested, how about taking those ideas to your first build once you break in the Sport? If you grow tired of the Sport you can always sell it as you go it and not have to worry about explaining all the "alterations" you subjected it to.

They nailed it...I understand the wanting to change it out. I have changed gas blocks a couple of times and that would be what you are up to. I myself would consider going to some sort of free float rail or handguard with a rail when you change the gas block. But you can just change the gas block with a railed block but then you have to find the right size and you cannot just mount the Magpul sight to the gas block. Lots of little things but nothing difficult.

We can help you if you want to do this, just think about what your end goal would be at this time, hopefully we can help you avoid the pitfalls.

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Grover Oathkeeper