Hi I just recently purchased a Colt LE6920. New to the 5.56 world.
What's some decent but relatively cheap ammo I should stock up on?
I always hear stuff like M855 and M193.

Just looking for some opinions, THANKS!

For plinking go with Wolf Gold.

I mainly shoot my own reloads, but my go to ammo stash is mostly Wolf Gold 55gr FMJ.

Wolf Gold
American Eagle (Federal makes)
Federal xm193
PMC Bronze
Geco

All of these are relatively cheap now and all should be good stuff.  

The first few paragraphs here are a good and quick read.

https://www.ar15.com/ammo/project/term_m193orm855.html

Welcome to the black rifle disease!!!

thanks for the reply guys.
I've had my AK for a while so I know what's good in the 7.62x39 caliber, now just trying to get to know 5.56.

Everyone is referring to 5.56, not AK ammo.

Wolf Gold is probably the best out there value wise.

WOLF GOLD

M855 and M193

I know that. I was just talking about my knowledge background.

I stack up Wolf Gold and AE223 for plinking and 3 gun.
I keep a case or two of XM193 around for SHTF because of its sealed necks and primers.
I keep 300-400 of IMI 77 razor core loaded in mags for HD.
I hand load either 77gr SMKs or 75gr BTHP for precision.

Lol....gotcha.  Wasn't sure with the way you had it worded.  A lot of people still don't realize that Wolf imports more then just steel AK ammo.

I'd get some ammo to shoot, and wait to stack deep.

Not match, but reliable and accurate enough. M193 "clone", as pretty much all 193 is now days. Less than 34 cents per round delivered, not shabby right now. Wolf Gold is tough to beat.
I don't care for M855, never have.

Have fun.

All I stock for plinking is  XM193.

Another vote for Wolf Gold.

Prvi M193 is another good and affordable option.

LC XM193

And I would buy at least a few boxes of steel cased Wolf or Tula just to make sure they function in your rifle. Who knows, it's the cheapest option and you might like it for range ammo.

I still got plenty of IMI 55gr, PMC Bronze and X-Tac and Federal XM-193 but I only stock up on Wolf Gold now. Its my 55gr SHTF ammo for if I run out of my 77gr MK262 rounds.

M193 would be a good round to use for your first class, as well as general plinking

Wolf Gold 223, 55 grain for range
PMC X-Tac 5.56, 55 grain of "serious" work
Jump on this deal quick
X-Tac

Wolf Gold for practice

Speer Gold Dot 64 grain or Fusion 62 grain for defense

For me.
Lately Wolf Gold for regular shooting (buy it cheap stack it deep)
IMI and Federal 55grn (my regular shooting rounds before Wolf Gold)
Several cases LC XM855 green tip (Just because)
Federal Fusion MSR 62grn HD / SHTF round (pick some up every trip to Walmart)
Starting to stash 75grn PPU for my "poor man's" RECCE

Buy a little bit of different rounds and see what your gun likes.

My go to ammo has been IMI for the last 10-15 years. Shoots fine out of 85% of my rifles. Out of damned close to 10k rounds, I've never had a FTF, squibb or any other type of mishap. Most of what I've got was made around 2005 & 2012. I stopped buying all Fed/LC ammo. Just too dirty and it seems there's such better ammo out there for less money.
GGG is GTG. I'd consider it on par with IMI and feel confident it won't let me down.
I've got PRVI but just don't shoot it very often, hard to give an honest opinion, just don't shoot enough.
Lately been shooting the Geco in .223. I've been very impressed with it's accuracy and consistency. Super clean and definitely a keeper based on accuracy. I've not tried the Geco in 5.56 but plan on trying it out.
I'm still shooting Guat, Radway and SA in 5.56. Was fortunate to stack that stuff really deep.
Guns are LMT's, Spikes, Colts and Knights Armament. Barrels are 16 & 14.5. All are 1:7.
Thing to remember is it seems no two barrels are alike. Two identical LMT's one will shoot the newer .223 Geco @ 1.5 MOA all day long. The other is closer to 2.5 MOA. Yet the one that shoots the Geco not so great is very impressive using older IMI made Winchester Q3131.
Give Geco a try. Sam at SG usually has it, but has been out for a while. Hoping he's due for more anytime...I want more!

for plinking I like Wolf gold and PMC Bronze. I also have a bunch of Priv Partisan M193 but it costs more than the other two.For defensive I'm using ADI loaded with 69gr SMKs and will switch to PMC X-Tac Match 77gr OTM when the ADI runs out.

Personal preference, but in no particular order:

1) Speer GD 55 and 62. A little 75
2) Magtech 77 OTM
3) Winchester Ranger 55 PSP
4) Fiocchi SP
5) Australian Outback 55 vmax
6) Federal 50 varmint and Wolf Gold 55

I have a stash of Federal XM193. I pick up some every time  Cabelas runs it on sale, shoots real well in both of my AR's and the LC brass is an added plus.

Vince

I see those a lot on sgammo and have been wondering about them. I keep meaning to buy some black hills 77 gr otm for HD. The razor core is cheaper though.

If I were starting a new stash today with what is always available in my market, for my uses and proven to work well for me: (These are really all I am buying nowadays anyway)
Wolf Gold for practice and classes.  Pretty much always available at my local ammunition supplier (The Armory)
Federal Fusion for HD/SD.  Always on the shelf at Walmart.
PPU 75gra OTM for my "RECCE".  Pretty much always available at my local ammunition supplier (The Armory)
That being said, don't discount any other quality ammunition you find for a good price.  About the only thing I don't buy is Green Tip as I have a lot and I cant shoot it at steel where I shoot.

This is what I do with the addition of the 77g TMK

Lots of good advice given here. The only thing I would add is that if you think you're going to start reloading 5.56, I wouldn't get a lot of PMC. The brass is very soft and very touchy on crimping. It's way too easy to buckle the shoulder. I never have that issue with any Lake City or other annealed brass. I like the Federal American Eagle ammo because it's LC brass and seems widely available.

don't listen to anyone here, lots of good brass suggestions but you need to shoot as a newbie and shoot often

you are new so you need to shoot often, learn the firearm inside and out, get comfortable with it

you can buy 1k wolf steel for 220 delivered. I'd buy 2-3k and blast away.  It's cheap, reliable, safe, accurate enough and won't give you any issues.  You will save 80/1k.  The savings get you a nice red dot, familiarity and rounds downrange at 2/3 the price.  You need to shoot

you are welcome:)

As a few others have stated, I reload so generally don't fire factory new very often, but when I do and, Just an opinion here... But when you can find the FMG Norma Tac 223 on sale, get it! Stuff is scary accurate out of any of my AR's and the brass is excellent for reloading. If you don't reload, pick it up and sell it, it's that good.