[Angry_bald_guy]

Ok, I'm fairly new here and the only gun I have owned so far is the 1911 that I currently have. I've been looking at building an AR-15 for a SHTF situation and was wondering about the .308 chamber for it. I have a few questions about it and would like to use your experience here.

First of all, will a standard AR-15 lower work with a .308 upper?

Second, will a standard AR-15 mag work with .308 win rounds?

Third, what is a gas piston assembly for an AR-15 and what does it do?

Last, what is the difference between an AR-15 and an AR-10?

Thanks for your time and help.

[spittinfire]

The 308 will not work on an AR upper nor can it use standard AR mags. The 308 is an AR10. It's the same basic platform but due to the longer cartiridge you need a longer bolt cycle. There are commericial loads such as the Remington 30 AR that are .30 and designed to work on an AR15 platform and mimic 308 balistics but a tat pricey.

The AR is gas operated which means it uses the hot, pressurized gas from the discharged round to cycle the action. Most use a tube which direct the gases back to the bolt and push it to the rear. I personally can see no reason to go with a piston system unless you just want it.

Does that help? There are people here who know a lot more about ARs who will be along shortly if you need more info.

[mjkeat]

Originally Posted by spittinfire

The 308 will not work on an AR upper nor can it use standard AR mags. The 308 is an AR10. It's the same basic platform but due to the longer cartiridge you need a longer bolt cycle. There are commericial loads such as the Remington 30 AR that are .30 and designed to work on an AR15 platform and mimic 308 balistics but a tat pricey.

The AR is gas operated which means it uses the hot, pressurized gas from the discharged round to cycle the action. Most use a tube which direct the gases back to the bolt and push it to the rear. I personally can see no reason to go with a piston system unless you just want it.

Does that help? There are people here who know a lot more about ARs who will be along shortly if you need more info.

THis is it in a nut shell ^^

[Dillinger]

Originally Posted by Angry_bald_guy

First of all, will a standard AR-15 lower work with a .308 upper?

Second, will a standard AR-15 mag work with .308 win rounds?

Third, what is a gas piston assembly for an AR-15 and what does it do?

Last, what is the difference between an AR-15 and an AR-10?

Thanks for your time and help.

1) As indicated above, that would be a negative.

2) Again, as indicated by Spitty, negative.

3) The gas piston system is an "improvement" to a problem that doesn't really exist if you take care of your weapon. The gas piston system takes the place of the gas tube system and makes your AR run more like an AK. The gas pressure is harnessed at the muzzle end of the weapon and forces a piston backwards to cycle the action. In the current design, the gas itself creates the expanding pressure to cycle the action. The piston system is more reliable, if you are prone to dragging your weapon through 60 yards of mud and wet concrete before shooting it, but it is not as accurate as the standard gas system. It's a trade of, a little more reliable for those that abuse their weapon and a little less accurate. So what you have effectively done is created a really expensive AK ( in my opinion and that of others I know )

4) As indicated above - the AR-10 is the classification for a larger sized, big brother version of the AR-15. There are tens of cartridges that can be custom made for either model, but it comes to case size. For the larger rifle calibers like .308, you need AR-10 parts. For smaller applications like the 5.56/.223, you need the AR-15 parts.

Hope that helps!

JD

[TheDaggle]

If money is a factor, you may want to go the 5.56 route. Ar 10s are much more expensive. I don't know what .308 ammo costs, but I bet its more expensive, as well.

[canebrake]

First build? Don't complicate it!

I would go with a RRA complete, direct impingement, 5.56 Nato upper and build the bottom end.

Rock River Arms: .223/5.56mm Upper Halves

I went with a quality, multi-cal, billet, stripped lower. When you start with this good of a foundation it opens all sorts of upper swap-outs.

Rainier Arms, LLC™ Mega Billet Lower - GTR-3S

I highly recommend Rock River Arms and Rainier Arms for your AR build parts.

[Angry_bald_guy]

Thanks for clearing everything up everyone. I am already getting a .308 bolt action and was looking to keep similar ammo stocked instead of changing calibers, but I'll give the AR-15 some thought instead.

[dog2000tj]

Why not get/build and AR15 and an AR10?

[Angry_bald_guy]

Originally Posted by dog2000tj

Why not get/build and AR15 and an AR10?

That's what I'm leaning towards... But I was hoping to do an AR10 first time out.

[dog2000tj]

Well you will have loads of choices if an AR10 is indeed the way you go. All the big names make a lower and more and more are coming out with complete rifles.