.308 AR vs 6.5/6.8

[AirborneStranger]

I am thinking of getting a nice target rifle and it occurred to me that I still have an AR lower that I haven't built yet, so I was thinking about using it to build a 6.5 or 6.8 AR. I am new to specialty AR's so forgive the stupid questions but I was wondering the following:

1) Will a .308 or 6.5/6.8 AR "keep up" with a bolt-action .308? My main reason for building this rifle will be shooting it with my cousin, who has a savage .308. Will an AR be able to hit out there with a bolt-action or am I expecting too much? Obviously the biggest factor will be my shooting ability, but assuming I am a good shot will it keep up?

2) How comparable is a 6.5 or 6.8 to a .308? I would prefer to use my lower that I already have versus buying an entirely new gun if I go the .308 AR route.

3) 6.5 or 6.8 will both work using my existing AR magazines, right? (p-mags)

4) Finally, I might be asking for it but which is the better bet, 6.5 or 6.8? It seems like they both cost about $1 a round, are they fairly comparable in other respects?

thanks in advance, I bow to your guys' superior AR knowledge

[slomofo]

I'm not sure if you were aware of this, but the .308 round isn't going to fit through the magwell of an AR-15 lower receiver, so you're left with 6.5 & 6.8 which is extremely expensive to shoot unless you're a reloader.

[THT]

1. Yes however shooting a precision gas gun is a completely different animal than shooting a bolt gun.
2. Don't consider the 6.8. Poor external ballistics. The 6.5 bucks wind really well so it makes for a great long(er) distance round.
3. No
4. 6.5 has superior external and terminal ballistics past 200 yards and equivalent to 6.8 within 200 yards.

[thrillhouse700]

I asked this same question a few months ago so I will try and answer some of them.

Basically a .308 AR will compete with the bolt action better as the round has more power and good ballistics at further distances.

The 6.8 and 6.5 are nice but are more expensive than a .308 round.

[pyro3k2]

You have to spend a good amount of money to make your .308 AR as accurate as bolt gun. My .308 AR can shoot just as good as my tikka varminter in the same calibur, this major difference is with the cost of just the upper I could have bought the rifle, a Vortex optic, and some boxes of ammo. With the AR I still have a lower, mags, optics, and ammo still to buy. If you are shooting within 400yards use your AR, if you are shooting past 400yards use you .308 bolt gun.

[Linkpimp]

I think most AR 10 shoot at 1 MOA, no? so I would say that yeah, a good 308 AR (LAR 8, comes to mind) can go toe-toe with your buddies Savage.. No concerns there on the rifles part..

6.8 & 6.5 are fun to shoot, hit hard, but as other have suggested they are expensive to shoot. Even if your reloading, your bullet choices are limited.. But they are great calibers..

IMO the 308 is cheep to shoot, provides more than ample stopping power, offers tons of verity of different ammo to shoot, they are extremely accurate (well then again, you get what you pay for), etc, etc, etc..

[thrillhouse700]

For me, an AR-10/LR308 and a bolt gun can both out shoot me so I chose to go with an LR308 until I get the urge to learn long distance precision, which im sure will come soon enough.

[killshot44]

I am thinking of getting a nice target rifle and it occurred to me that I still have an AR lower that I haven't built yet, so I was thinking about using it to build a 6.5 or 6.8 AR. I am new to specialty AR's so forgive the stupid questions but I was wondering the following:

1) Will a .308 or 6.5/6.8 AR "keep up" with a bolt-action .308?

Yes

2) How comparable is a 6.5 or 6.8 to a .308? I would prefer to use my lower that I already have versus buying an entirely new gun if I go the .308 AR route.

6.5 whips a .308 ballistically. 6.8 is a poor long-range choice. As mentioned, .308 requires an AR10, 6.5 will work in a AR15.

3) 6.5 or 6.8 will both work using my existing AR magazines, right? (p-mags)

No. The mag body is the same but not the internals.

4) Finally, I might be asking for it but which is the better bet, 6.5 or 6.8? It seems like they both cost about $1 a round, are they fairly comparable in other respects?

Not at all. The 6mm and 6.5mm chamberings available to an AR15 are vastly superior to a 6.8spc - but you're going to handload (which any serious long-range shooter does anyway).

All of the above is for target shooting only.

Thanks in advance, I bow to your guys' superior AR knowledge

If you don't want to handload the 6.5G is a good choice, get a long barrel.
If you will handload, 6.5G is still good but some other 6mm chamberings are better. (6BR, 6BRX, 6BRAT, 6mmARt40)

Really comes down to what you want to do with it and how much you can spend.