Who makes the best AR15 rifle in 5.56?

Answer 1

The only company which actually manufactures the AR-15 is Colt, as they have the trademark to that name.

As for AR-type rifles, "best" is extremely subjective. If you want something custom, I'd recommend you get a stripped lower and either build your own or have one built for you. ANY milled or billet receivers which are within specs will work just fine.

If you browse around the wonderful world wide interwebz, you may come across a site - AR15 dot com. That forum has some of the most elitist AR owners alive - and most of them don't have a clue as to what they're talking about. They will insist that your rifle MUST have these things in order not to be "junk", and a gunsmith, competitive shooter, combat veteran, and FFL holder is going to debunk them as they are listed:

• Colt or Noveske: Neither company manufactures their own receivers - they outsource them. And the companies which make their receivers also make them for other companies which people on that forum would deride as "junk". Like I said before, any forged or billet receivers within specs will do just fine - just avoid the cast ones (e.g., Hesse, Blackthorne, Vulcan).
• 1 in 7 barrel twist: This is an utter crock, and only proves my point that these people don't know what they're talking about. The military went with a 1 in 7 barrel twist because it gave the same flight characteristics to the 64 grain tracer round as the 62 grain ball round. 1 in 9 is actually the ideal rate of pitch for the 62 grain 5.56 NATO round, and it is also fast enough to accommodate lighter cartridges (such as the 55 grain 5.56 M193, 55 grain .223 Remington, and 45 grain .223 Remington). Even Hornady recommends a 1 in 9 pitch for their 75 grain TAP rounds. The only time you need a slower pitch than 1 in 9 is if you're firing 77 grain rounds like the Mk. 262 or the 80 grain .223 Wylde (which also requires a .223 Wylde chamber). Even then, 1 in 8 is actually the recommended pitch.
• Chrome lined barrel: Unless you're firing an extremely high volume of ammo, or firing on full auto, this actually works against you. Chrome lining impairs accuracy, first off - that's why sharpshooter variants of the M16 used by the US Army and US Marines, as well as other sniper rifles, do not have chrome lining - it makes the bore excessively tight, and imperfections in the chrome lining further impede accuracy. On top of this, several manufacturers make chrome lined barrels and claim them to be 'mil spec' - this is a crock, as they do not know what those specs are. So they put on a cheap chrome lining which is prone to flaking, and that just kills the accuracy of the rifle.
• M4 feed ramps on the upper receiver and barrel: While it doesn't hurt to have them, the AR has been around for a long time without the extended feed ramps, and has done just fine. You just don't want to combine a receiver with the feed ramps with a barrel without the feed ramps. Feed ramps on the barrel and receiver is ideal, and feed ramps on the barrel but not the receiver is just fine, as well.
• Military style staking of the gas key: Many companies offering AR platform rifles do not stake their gas keys this way. And they still stay attached to the bolt carrier. If this worries you, the gas key staking can be done by a competent gunsmith for about $20 - $30.

So don't pay these dolts too much attention. If you have further questions, you're free to email me (my email address can be found on my bio page).