as you can see, everyone has an opinion, and a reason (real or perceived) as to why something is best, good enough, or no good at all.
Personally, I lean toward BCM, Noveske, LMT, and a couple other small companies I support, but I have a few Aero's around for fun too.
As mentioned, an adjustable gas bock is great if you need to go between suppressed and unsuppressed, but otherwise, get the gun running and never touch it. Cheap barrels tend to be overgassed, though some higher end stuff will be too. You can work with buffer weights to slow down the BCG in most cases, though.
IMHO:
If it is a fun gun, not serious use, I wouldnt mess with BUIS with a 1-6. Do a non adjustable that will work with the handguard cap (or chop yours - easy, quick, free, and no one sees it when the rail goes on anyways - mine below), and later you can add a free float rail. I would spend the $$ you were going to spend on a new gas block and sights on a cat-tail for the scope and a new rail. Aero makes some pretty decent stuff for a budget rail (though a bit large in diameter), as does Seekins (and FYI, the Primary Arms rails are made by Seekins, as are a few others). ALG makes a GREAT budget rail as well, and is purported to have one of the best barrel nut systems. They are a sister company to Geissele. And Bravo Company's KMR is fantastic if you dig keymod, and want a small diameter rail.
Lots of others too, but those would be where I would start.
But to just run with a "budget" in mind:
A Aero Quantum rail: $85, 12" with bbl nut
Chopped FSP - Free (if you have tools)
3 Gun Stuff cattail - $30 Polymer (primary arms), about $60 if you want metal.
That gives you the ability to free float, and quick adjust from 1-6 as needed, and since the scope has a etched glass reticle, you are still good if a battery dies.
Start:
After the cut of the sight post
Shaping
Shape after:
This is on an LMT barrel with a pinned flash hider, so removing it wasnt an option. I masked and cut, and ground to shape, then touched up with paint. I had to cut off the hand guard cap, so there is a gap between the shoulder and the gas block, but it is a pinned block, no worries about it sliding.
You can do the chop (very carefully!) and reinstall with the handguard cap still in place, as a temp thing if you want as well. Its just kind of ugly unless you are really careful/good with the grinder and spray. But who cares?
