This may sound like a dumb question, but I haven't had a lot of in-person experience with rail systems so please bear with me. I've ordered a new Bushy M4A3 type rifle and am looking into options for a rail system.  I had assumed that the available systems required the removal of the FSB and FH but the more I read, I'm thinking that only the free-float types require this.

Can anyone offer some insight? Do the non-FF rail systems require FSB removal or do they fasten on like the regular handguards?

Thanks!

With the RAS and RIS, you don't need to remove anything but the handguards.

The RIS/RAS/, Surefire M73 and YHM slip right on like handguards, most of the FF require taking the FSB and barrel off, etc.  There are a couple of hand guards that free float that can be done without taking the barrel off, the SIR and Troy industries are the only ones that come to mind, but I am sure there are more.

Get a RAS II (or Troy MRF, but I don't have experience with the Troy) and you can free float the barrel without removing the FSB.

The RAS II does free float, and does not require the removal of the front sight tower.

check out > www.quarterbore.com/library/pdf_files/rasii22243inst.pdf