AR upper receiver

[devildog6133]

I need some help gents, I'm on the wall between a 308 and 7.62 upper receiver for my ar. Any suggestions?

 

[blksno]

Well since I already know you have a chip on your shoulder and you're probably going to take any post that I make personally. I'll be as forthright, honest and gentile as I can.
Step one, don't be so vague in your quest for knowledge. There is a lot of info from a lot of people, but if you don't ask the right question, how do you expect to find the right answer?

If you have an "AR"...what kind of "AR" is it that you have?
An Armalite AR10? A DPMS LR308? An AR15? Something else entirely?
It matters and you were not specific.

If you want a 7.62 or .308 for your "AR"...are you talking about the caliber of bullet, or are you talking about the cartridge itself? You can get a uppers for an AR15 that operate 7.62 caliber bullets...but they are not 7.62 NATO rounds.
It matters and you were not specific.

If what you mean is that you want an upper receiver that will fire either 7.62 NATO rounds....OR....a rifle that will fire .308 Win rounds. Then choose an upper chambered in .308. You can shoot both out of it. You still need to know what platform it's going to couple with.

I don't even know anyone that makes a dedicated .7.62NATO chambered rifles...they are usually all listed as cross compatible because they have a SAMI .308 Win chamber.

 

[devildog6133]

Well since I already know you have a chip on your shoulder and you're probably going to take any post that I make personally. I'll be as forthright, honest and gentile as I can.
Step one, don't be so vague in your quest for knowledge. There is a lot of info from a lot of people, but if you don't ask the right question, how do you expect to find the right answer?

If you have an "AR"...what kind of "AR" is it that you have?
An Armalite AR10? A DPMS LR308? An AR15? Something else entirely?
It matters and you were not specific.

If you want a 7.62 or .308 for your "AR"...are you talking about the caliber of bullet, or are you talking about the cartridge itself? You can get a uppers for an AR15 that operate 7.62 caliber bullets...but they are not 7.62 NATO rounds.
It matters and you were not specific.

If what you mean is that you want an upper receiver that will fire either 7.62 NATO rounds....OR....a rifle that will fire .308 Win rounds. Then choose an upper chambered in .308. You can shoot both out of it. You still need to know what platform it's going to couple with.


I don't even know anyone that makes a dedicated .7.62NATO chambered rifles...they are usually all listed as cross compatible because they have a SAMI .308 Win chamber.

No I do not have a chip on my shoulder that was a different thread entirly, and that is my bad for being vague, its a bushmaster ar 15 shooting .223 now, and I'm not real sure about the .308 or 7.62 , from wat you've said you pretty much answered. My goal is to have a long range ar 15, my question was which caliber of bullet would be better suited, since the 5.56nato or .223 is only going to effectivly reach out to about 550-600 yds. It's pretty obvious you know "your stuff" and I hope that we can put wats behind us in the past, I can tell I could learn quite a bit from you and others on this site, so here's my apology.

 

[blksno]

I'm about to use two subjective terms and I will describe what I mean in parenthesis because I don't like to use subjective terms.

Some of the best (balisticly) long(er) range (beyond 800 yds) calibers for the AR15 platform are as follows.

The 243 and 25 WSSM are capable of pushing high bc bullets at velocities that retain enough energy to make kill shots at or beyond 1000 yds.
The 243WSSM is capable of shooting 105gr bullets upwards of 3200 fps. Hard to beat in the AR15 platform.
The 25WSSM may not have the bullet selection, but can push the 105gr bullets at or beyond the speed the 243WSSM can...with less pressure due to bore diameter.
115gr bullets are also possible in the 25WSSM, and are nearly impossible in the 243WSSM.

The 6.5 Grendel may not have the velocity, but with the ability to push 123-140gr bullets...you can rely on the BC to achieve what most smaller calibers cannot.

The 6mmAR / 6mm AR Turbo / 6mm ARTurb0 40imp / 6mm Rat are all pretty much the same variants with minor chances to case capacity. They also don't have the velocity, but you don't have the issues of excessive barrel wear or ultra unique bolt/carrier parts like the WSSM's have.

I believe the 6mm bullets to be the right mix of speed and bc in the AR15 platform....by jumping up to the 6.5, you really start to run out of magazine length quick.

You could run the 300OSSM, nearly .30-06 ballistics but again, you're looking at a specialized bolt and carrier.

I personally consider 600-1200 yds MIDrange...but this number depends on experience and equipment.
In the AR15 platform, it's a far poke, no question, and I consider 1200 about my max with the 243WSSM and 105Amax. Beyond that, I'm just throwing them out there.

If you really want to be shooting LR, then you should consider stepping up to the next platform. The 223 can handle punching paper and steel out to 1000 with the right bullet/barrel combo and it's good practice to do it, so you might be better off saving up for something like a 6.5Creedmoor or 260 in a large frame AR, in either the Armalite or DPMS/SR25 style. The days when .308s were a hot item are pretty much over. The .6.5 cal bullets just out perform them in nearly every category.

 

[Deleted member 48126]

At devildog...I don't think there is any better of a suggestion/ information than what you just got from Cbass. Just realize when you get away from the .223/5.56 platform components start changing as Cbass stated, so it can be more expensive and harder to get parts. Also, out of curiosity what did you mean by 308 or 7.62? Did mean the 308 Winchester vs the 7.62x51 NATO chambering? I have an AR in .300 whisper that I love but that is no means a long range .30 cal AR.

 

[notajeep]

May not be exactly what you want, but why not build a quality 30 cal upper? Get the length, twist and chamber you want. They do it for AR-15's, so I'm guessing it can be done for the AR-10's.

 

[LouBoyd]

Consider not only supersonic range but also wind deflection in choosing a long range cartridge.
My longest range AR-15s are:

6mm PPC - M1S
243 WSSM - Olympic
6.5 mm Grendel - Alexander Arms

All have 24" barrels All can reach 1000 yards supersonic, at lest where I shoot in Arizona. All can feed from a standard AR-15 lower though they require slightly modified magazines.

They are not the same though. The 243 WSSM has the flattest trajectory but the worst wind deflection. There are no doubt some wildcat cartridges which can do as well, maybe better.


The 300 OSSM isn't close to a 1000 yard cartridge. In an AR-10 I don't consider the 308Win/7.62 NATO to be a 1000 yard cartridge. The 6.5 Creemoor gives the best range & wind deflection performance of any commercially available AR-10 cartridge I'm aware of.

 

[devildog6133]

Thanks gentlemen for the info you've been very helpful after a good bit of thinking I think I'm goin to go with the 6.5 creedmoor. I'll let yal know when I make the final decision on the purchase for further advice. In the mean time do any of you know of any 800-1200 yard shooting ranges around North Western Nc?

 

[blksno]

The 6.5 Creedmoor isn't going to fit on your AR15 lower you know.

But kudos if you're buying a complete new rifle...might as well have another pony in the stable!