Do you want to replace your hanguards with a 4 rail or not? If you do there are any number of systems out there just depends on what you want to spend.I have the Surefire M73 on mine for about 190.00. If yo want to keep them there are some little shorties that mount in front of the front site. There are also rails that mount on the factory guards. Ncstar makes a set for about 15.00
I have this one and I love it. It fit perfectly on my BM A2, but I had to trim a tiny piece of plastic off for a perfect fit on my M4. definitely worth the $15
__________________ turning up the radio, got just enough religion and a half tank of gas...