The best, now even better - Faxon Firearms Streamline Gen2 Handguard 1

I was surprised to find when this finally arrived at my door (it's been out of stock for months) that there was good reason for the delay. They've made a number of non trivial improvements. Most notably the first M-Lok slot forward of the receiver on the 12 o'clock plane is no longer cut out which keeps the stepped up portion in the gas tube away from your fingers. You don't lose any functionality here since the gas tube was so close to the outer diameter you couldn't get any M-Lok nuts in that particular slot anyway. The second major improvement is a pair of lugs at about 11:45 and 12:15 to index the whole unit true to the upper receiver (I don't fully recall but I believe these index along the flats under the picatinny so it'd be compatible with any railed upper). This aids in assembly and keeps you from having to clock the rail by eye as with the old model. Plus, it'd mitigate any potential chance of the rail getting out of clock in use (has never been a problem for me and with the 4 set screws plus two clamping bolts likely never will be). The third and final improvement I noticed is a nice Faxon logo milled into both sides, I only wish they included their shield logo in addition to or instead of their stylized name. My only star deduction is for the somewhat exorbitant price, but, to be fair, it's the best carbon fiber handguard on the market which by extension means it's really the best handguard on the market period.