Best? you'll get a different answer from each person.
What is your budget?
What will you be doing with the rifle?
What will you be hanging off the rail?
Do you want drop in, free float, etc?
UTG is a very affordable drop in. I found that the material seemed softer than most AR parts. Otherwise it will work.
There are quite a few drop in quad rails below $150. YHM, Troy, Midwest Industries. All are very good quality.
Look at Primary Arms.
October 1, 2012, 11:14 PM
Looking for a drop in under $100. I would like to be able to hang a light off it and a handgrip.
October 2, 2012, 05:31 AM
Magpul MOE with accessory rails. Approx 35 for the handguard and 8-10 for each rail.You can also avoid the bottom rail by purchasing a Magpul front grip designed to attach to the handguard, lowering your cost.
October 2, 2012, 02:27 PM
I'm not real fond of how the magpul looks. i don't like the fact that you have to purchase and install the rails separately. I like the looks of the tradiional quad rail. My concern is that I get the correct length and the gas tube has the proper clearence. I've seen carbine length quad rails range fron 6.5 to 7 inches in length. The first one recommended on this thread measured 6.7 inches in length, which happens most closely match the foregrip on my DPMS Oracle. For the quad rail to drop in, I would assume that it would have to be the exact length of the original grip. Is there any leeway I n the length of the replacement?
October 2, 2012, 03:53 PM
My first suggestion would be the Magpul MOE forearm as well. It will do anything an aluminum drop-in quad rail will do, and it will do it while being lighter, less expensive, and more ergonomic.
That said, if you must have a drop-in quadrail, a good choice would be the Daniel Defense EZ Rail: