Hi everybody, new guy here. I just put an M&P 15 in .223 on lay-a-way. It's the one with the flat top and gas block system. I'm looking to get into a 3 or 4 rail Picatinny forend that will fit it and would like to hear some suggestions. Are all forends interchangeable with this rifle or just certain ones? This is my first AR after getting out of a piece of junk KelTec. I don't know too much about AR's other than I have wanted a good rifle for a long time, so any advice would be good.
Thanks