So I have convinced myself that I want to build an AR-15 in either 6.5 Grendel or 6.8 SPC. I would like it to be lightweight, and handy, but still capable of 300yd shots on whitetails. Any advice on 'must have' components and 'must avoid' components is appreciated.

I would suggest you not get caught up in billet vs. forged - they both work quite well and I would not pay for a name brand lower or upper receiver. Quality barrel, BCG (ck headspace) and a good fire control group and you're there. I would prefer the Grendel but the truth is bullets make the difference, not headstamps.

Good luck & Have fun!

get a good barrel, I would suggest an ARP 16" scout profile 6.8 or 18" and would also get one of their super bolts, they will check headspace for you if you buy both and ask them to. good barrel at a fair price. 6.8 is hard to beat for a light short rifle and packs plenty of punch for 300 yd deer.

last year was my first for the 6.8 and it put my Grendel in the safe to stay.

I would suggest a forged upper if weight is a consideration, dosent have to be the most expensive thing out there, same goes for the lower. a decent float tube that's light weight will be a plus. for a hunting gun I like a round tube, I have several JPs and like them but there are tons of float tubes out there. YHM makes a good inexpensive gas block, again no need to buy high dollar.

I have Magpul STR stocks on my 6.8s, light and pretty comfortable but again just personal preference, lots of choices to be had.

I would give hard consideration to a Rock River two stage varmint trigger, hard to beat for the money. bolt carriers don't have to be high dollar to work well and there are many out there to choose from. I have a threaded cap on my latest 18" ARP barrel and its almost as short as my 16" with a flash hider plus you can shed a ounce or two.

Just one opinion among many, good luck with the build...

An accurate 223 will kill deer dead at 300yds just as will an other similar caliber. The biggest thing I will impart is if you have a budget buy a cheap rifle, lots of ammo and shoot a lot. Don't get stuck on names or barrel lengths, good optics and lots of ammo.

Adam

Squeeze the little "C" clip on the hingepin for the dustcover. Don't hammer it on, or you'll likely launch it into parts unknown.

Even better, buy a hingepin with a clip already installed.

When building any AR , put your money into the barrel and the trigger, the rest doesn't have to cost that much. Any upper, lower receiver and bolt group will make you a good hunting rifle. 6.8 SPC Barrel , my pick goes to Bison Arms .

Personally I'd avoid anything shorter than 18 or 20 due to noise... I hate 16s....

Other than that, good barrel, setup correctly with a matched bolt and would be unusual to not shoot under MOA.

It doesn't take much accuracy for 300 yard chest shots on deer so you might not need the best barrels out there.

A good trigger doesn't make the rifle more accurate, but it does make it easier to shoot accurately.

Float tube really isn't needed unless you will shoot with sling tension or a bipod.

My 6.8 i built with a 18 inch tube on a Left Hand Stag Upper. This the first 3 shot group from the rifle after i built it . With SSA Factory ammo

Avoid slow trist

I would not shoot a deer at 300 yards with a 223, most people like to shoot short barrels like 16" heck I worry about putting down a coyote with a 16" 223 at 300 yards.

I prefer the grendel for your purposes the problem is getting grendel stuff is impossible right now. yeah you can pay through the nose and buy stuff second hand. My grendel is on hiatus, I can't get the right bullets for it much less ammo.

as for pitfalls put your money into a good barrel and a good trigger save you money for ammo.

I've shot deer with 20 inch tubes on the other side of 500 with irons to boot.. in 223 with 75 amax... not an issue yet.

Might not be the ideal choice, but out to 300 there isn't any question it will get the job done no problem.

If you have an issue with a 16 inch tube putting a yote down at 300, before I'd suggest a longer barrel or larger round that you buy a book on anatomy.

Thanks for the advice so far. I was leaning toward an 18" Grendel barrel, but haven't found a lot of options. Which maker do you guys/gals recommend?
Thanks

Alexander barrels are Lothar Walther, ok but not top line in my books. But suitable for most.

If I was after accuracy I"d be talking to a smith that does barrels, and get a Krieger or Rock or such done in the caliber you want. I would not be chasing a pre made barrel...

6x45

If 6mm is a must

I bought a 20" shilen, only thing I don't like is its pretty beefy under the handguard, it steps up twice behind the gas block. it would be awesome if it just stepped up once and stayed like that all the way to the shank

anyone ever use a Wilson Barrel?

If you want a really awesome trigger for the money, consider an ALG Combat Trigger. Nickel Boron and tuned by Geissele for $65. I have one an it's easy to shoot, and I'm used to excellent triggers on bolt guns.

http://www.joeboboutfitters.com/ALG_Defense_Combat_Trigger_ACT_Tuned_By_Geissele_p/alg-act.htm

I have a 20 inch Wilson barrel and it is very accurate.

cheaper here... LINKY

Have to specify which Wilson.

Wilson Combat is not the same as Wilson Arms, who makes barrels for several AR manufacturers.

Thats the fault of competitive shooters. We desire weight. Its a good thing for us.

Finding top line barrel quality with light hunting barrels has always been tough in the AR lineup unless you go custom.

We used Wilson, not Wilson combat, but whatever the wilson that RRA types sell, CLE, White Oak etc... as our practice tubes. Generally a .75 moa or better tube typically with the right ammo and I"ve been beaten by Wilson tubes.... I"d align them with douglas type quality, though my experience with douglas has been worse than .75 moa typically... but from what I hear they should be right in line with an average douglas

Hillbill mentioned it, this --> AR15performace 16" 6.8 ARP Scout. They have taken the SPCII chamber and made a few enhancements along with 5R 11.25 rifling for better accuracy and velocity. AR15Performance sells barrels directly as well as several other venders. I bought mine with a standard mil-spec bolt head spaced to the barrel from stutts tac. Would have liked the super bolt but no one has them in stock. I don't plan on hotrodding it so the mil-spec bolt will suit me fine.

The Grendel is good too but really needs a 20" tube to have any real advantage over the 6.8 .

Pitfalls? -Make sure the gas port lines up when setting your gas block...

I see no need for a super bolt... I've run higher than factory pressures in a LOT of ARs over many years and I've never had an issue with a standard bolt.

Over those years we've shot with SO many folks even out to Camp Perry most years and in that time I"ve seen exactly one bolt fail that was a colt bolt in a state match at Camp Swift Texas on a National Guard gun.