6ARC or 6.5 Grendel, talk me into either

[Casswick]

Im looking to build a uber long range AR, 20-22in barrel. I have already bought all the parts Ive wanted in the build, all in FDE or to be cerakoted later. An Aero M4E1 receiver set, Rubber CIty lightweight bolt carrier, SSA-E trigger, Fab RAPS stock. I was set on 6 ARC after talking to some PRS shooters at the Phoenix rod and gun club, but the more research i do, the less attractive it seems.

For one, Hornady is the only company supporting this round. As impressive as it is, the cheapest ammo is going to be $1.25cpr, Grendel can be had for half. There is far more third party support for Grendel. Finally, when you compare grain for grain, there is nearly no advantage to a similarly loaded Grendel round. Here is some data i found on 65grendel.com:

https://www.65grendel.com/forum/showthr ... k&p=309450

12” 6mm ARC
6mm 108gr ELD-M, 2350fps hand load with CFE223 or LeverEvolution, 23.8” Hg (higher altitude/lower air density where I shoot a lot), 59 deg F

300yds 1981fps 941ft-lbs 1.4 mil drop .5 drift
600yds 1643fps 647ft-lbs 5.0 mils / 1.1 drift
800yds 1437fps 495ft-lbs 8.1 / 1.6
1000yds 1270fps 387ft-lbs 11.3 / 2.0
1150yds 1118fps 300ft-lbs 15.2 / 2.6
1200yds 1085fps 283ft-lbs 16.4 / 2.7

12” 6.5 Grendel
107gr SMK, .230 G7 BC model, 2475fps hand load with IMR 8208XBR (~ 49,000psi), 23.8” Hg, 59 deg F

300yds 2053fps 1001ft-lbs 1.4 / 0.6
600yds 1673fps 665ft-lbs 4.7 / 1.3
800yds 1441fps 494ft-lbs 7.7 / 1.8
1000yds 1225fps 356ft-lbs 11.3 / 2.5
1150yds 1099fps 287ft-lbs 14.6 / 3.1
1200yds 1077fps 276ft-lbs 15.9 / 3.2

[QuietM4]

What do you consider "uber long range"?

And I see 6.5 Creedmoor is out of the picture since you seem to want the AR-15 footprint.

[Suck My Glock]

I think you answered your own question, and I agree,...the 6.5 is the obvious answer.

The only difference would be at higher altitudes. The thinner atmosphere at higher elevation gives a slight edge to the 6mm. But the thicker the air as you go down in elevation, 6.5 gains the edge. The 6.5 has a slightly better selection of possible powders to choose from as well.

[Creeker]

The Grendel is better as a 6mm in anything not SBR length. You’re looking at a neutered version in the ARC and basing your comparison on ballistics from barrels 10” shorter than what you’re intending to build. I don’t know where you got the data from, but I have a hard time believing there’s a 125fps gap between the two. That’s certainly not my experience with the 6mmAR and 6.5 Grendel and the ARC hasn’t been shortened that much. Also, I don’t think you’re going to find match 6.5 ammo at 60 cents per round. If you’re going to shoot steel case s*** then you’re dreaming if you think you’re going to beat out a 6mm with a match bullet.

Look at what is being shot in matches and it’s not the 6.5. XTC guys have been necking the grendel down to 6 since basically the day it came out. The ARC is Hornady’s attempt to take something already being done and tweak it just enough to call it their own.

[DuneShoot]

I'm a huge fan of Grendel. 1K yards is no problem.
Tons of factory ammo offerings or load your own.
Mine is a 18" suppressed. Shooting 500 yards or less is boringly easy.
I use 123gr ELDM's with 8208. Going to have to work up a new load with 8208 being non-existent.

[mtptwo]

Grendel is a wonderful round. AR format will not be an issue, as long as you get good mags.

It used to be cheap, with Wolf 100gr round, but now, the prices aren't so great.

[Kinked_Chrome]

If long range is the goal and you must build a small frame. Then 6 arc all day over 6.5 grendel. Id also consider the new 22 arc. If you only plan on engaging very large targets, 1.5mil or bigger, then maybe consider grendel. But 6 arc barely provides enough power to make a 6mm bullet get it done.

Get a quality barrel, with at least a +1 gas system. Maybe even +2 if you get a 22in barrel. Definitely get an adjustable gas block as well.

I shoot a ton of gas gun PRS matches and have built a several small and large frame guns in various calibers.

[BigNate]

As somebody else asked... what is "uber long range..." Some people might think that it's 1000 yards... others might think it's 5280 yards (3 miles). To shoot 1000y you are probably fine with either of the cartridges you mentioned (and a bunch of others). To shoot 3 miles - go build a 408 CheyTac... I get that the 3 mile thing is pretty ridiculous, but if you think that "uber long range" is say, 1760yards (one mile) - I'd suggest that unless you know that game and are challenging yourself to be able to shoot at that distance with an AR-15 - you are probably going to have more success (and more fun) if you move to a cartridge that shoots a heavier, longer, higher BC bullet than what you can get in the AR-15 platform (think 7prc, .300prc, .300Norma and up).

My 2 cents...

[Suck My Glock]

As somebody else asked... what is "uber long range..."

Well, considering 1 MOA is approximately 1 inch at 100 meters and 2 inches at 200 meters, etc;...assuming your rifle is capable of 1 MOA and you do your job PERFECTLY,...that is still a margin of error of 1 foot at 1000 meters. You only have to screw up just a tiny bit at 1000 meters with a 1 MOA rifle (or any rifle, really) to pull your shot off target.

And since few gundudes have ever put in the serious effort to be skilled enough to place accurate shots at 1000 meters (assuming they have the appropriate gear to even attempt it), I consider that to be "uber long range" for the average American gundude. For a trained sniper,...heck no. For a benchrest competitor, no. For BillyBob and his bargain built AK15,...this ought to be entertaining.

[Casswick]

As somebody else asked... what is "uber long range..."

I meant a "long range, uber AR-15"

[Casswick]

Anyone try WIlson Arms barrels lately? I was looking at their 20" fluted barrel.

https://www.jsesurplus.com/wilsonarms20 ... str-1.aspx

[Kinked_Chrome]

Anyone try WIlson Arms barrels lately? I was looking at their 20" fluted barrel.

https://www.jsesurplus.com/wilsonarms20 ... str-1.aspx

I have one of there 16in bull 223 wylde barrels that is a hammer. Some of the best groups ive shot are with that barrel.

[BigNate]

As somebody else asked... what is "uber long range..."

I meant a "long range, uber AR-15"

I guess I'm asking "what does 'long range' mean to you?" After that - are you talking about competing or just like "long range plinking." Different answers based on what you want.

I've got a fairly basic AR15 with this upper https://palmettostatearmory.com/psa-18- ... 46372.html and a Aero M4E1 lower with Gisselle SSA-E trigger and a quality stock. With 77gr IMI Razorcore (routinely on sale for about $1/rnd) or 75gr Frontier (about $0.90 each) match grade ammo it shoots well under 1MOA groups (I can consistently shoot .75 MOA groups and I'm guessing a better shooter can do better). The 77gr rounds stay supersonic to just under 1000 yards. I've shot a few "Accurized AR" matches with this gun - shooting out to 700 yards - and I'm clearly the limiting factor when it comes to performance in those matches. The gun is better than me - and I have less than $1000 in it. Unless you really want to work on things out past 700 yards - I'd just build something like this - and shoot match grade rounds for $1 or less and plink out to 500 yards with 62gr greentip stuff at $0.50/rnd or less.

If you are talking about competitive long range shooting at or past 1000 yards - I'd be looking at something that is not in the AR-15 platform... If you are dead set on the AR-15 then 6 ARC, 6.5 Grendel, or maybe .224 Valk are what I'd be looking at... edit - forgot - had read an article about the new .22ARC... might look at that too...

Just my 2 cents...

[Casswick]

My idea of a long range goal would be an IPSC silhouette at 1000yds.

[xerts1191]

https://www.accurateshooter.com/guns-of ... by-speedy/