Originally Posted by Scott3670
I'm a total newbie to the world of AR rifles and have what might be a dumb question, so please forgive me. Anyway, I'm in the process of deciding what type of quad rail (7") I want to put on my rifle (Armalite A15) but I want it to cover the d-ring. I've seen many pics where it appears that the rail/handguard is integral with the receiver. Can anyone tell me how to do this? Thanks.
While there are several rail options on the market that achieve this look, none of them will be a drop-in installation.
For the true monolithic uppers (receiver and rail are one piece), you will have to replace the entire upper receiver, and install your existing barrel, gas block and gas tube. Depending on the length of rail and gas system, you may be forced to install a low profile gas block, as well.
There are also rails that can be installed on your existing receiver, but these will require anywhere from a complete replacement of the barrel nut assembly (including D ring, spring, and retaining band) to cutting the D-ring assembly off of the factory barrel nut (or disassembling the entire upper to take it off without cutting).
Neither of these options are something I would suggest as a do-it-yourself project for someone new to AR-15s. They are definitely installs best left to a qualified armorer.
There are rails that you can install yourself pretty easily, but they will leave the delta ring assembly in place, and it will be visible. Anything from drop-in, non-free floated railed handguards (Troy, KAC, Daniel Defense, and others) to drop-in free float tubes with quad rails (DD, Midwest, Troy, and others). Most of these require little more than a screwdriver and/or allen wrench set to install. They range in price from $125 and higher, depending on brand.
There are cheaper options, too, but they tend ot be of lesser quality, and are more likely to come with out-of-spec rails, poor fit, poor anodizing, etc.