I have a Bushmaster A2 upper and a Anderson arms lower. I want to build a kiss AR that will be reliable and accurate. What is the best barrel quality barrel that want break the bank. All my other AR’s are flat tops with free float rails. I used a Daniel defense lt wt barrel on my wife’s gun but it is pricey.
Although it is not optimum, you can use a barrel with M4 feed ramps on an upper with “Rifle feed ramps…M-3…” whatever you want to call them. The nose of the projectile will “step down” into the M-4 ramps on the barrel. However, you cannot use an upper with M4 feed ramps on a barrel with Rifle… feed ramps because the nose of the projectile would then have to “step up.”
Not that I want to disagree with Will, but op if you look you can find the A2 upper with M4 feed ramps. I have two Colt A2 uppers with these. I don’t know if they still make them today but it can be found. My 20" has a BCM barrel I it and I found a 16" Colt barrel for the other one.
That’s weird. I can’t ever recall seeing an A2 upper (fixed carry handle with A2 sights) that had M4 styled feed cuts in them. I suppose someone could have made them or they were pulled apart from something else like maybe an M16A2 carbine or 727. But, I don’t recall if they had them or not.
Rock on with your A2 upper and barrel of your choice. Since this is a KISS build and you’re trying not to break the bank, and it sounds like you are trying to use parts on hand, just use your A2 upper and quality barrel of your choice. I built several for my agency using A2 uppers they had laying around unused (HBARs) with new M4 barrel assemblies. The M4 feedramps don’t cause hangups since it goes from high to low instead of low to high, and the F-hight FSBs only required a few extra turns of the FSPs to achieve zero with the fixed carry handle rear sights.
I’d look at the barrels from Sionics; you can get one with FSB, delta assembly, etc. for not a lot of money, and they appear to have good specs, although I haven’t used one yet.