• Frank's Lesson's Contest

    We want to see your skills! Post a video between now and November 1st showing what you've learned from Frank's lessons and 3 people will be selected to win a free shirt. Good luck everyone!

    Create a channel Learn more
  • Having trouble using the site?

    Contact support

An Argument

Skeld1

Sergeant
Full Member
Minuteman
Apr 20, 2010
220
4
42
Maine
A person I know claims that there is a way to run .308's in his AR-15 "just by changing the upper." I don't see how that's possible when a .308 round won't even fit through the mag well of his AR-15 lower, and I tried to tell him this, but he is insistent. If this were the case I'm not sure why anyone would be producing the AR-10/LR-308 guns? No, I'm not trolling, I just need some confirmation from folks who are more knowledgeable with this stuff than myself.
 
Re: An Argument

There is no way to run a semi-auto, .308/7.62x51 based upper on an AR-15 lower receiver. Hell, the magwell on an AR-15 is only roughly 2.6" in total length (internally) which in and of itself is roughly 0.20" short of the OAL of your average .308/7.62x51 cartridge. Now, at one time, I believe that there was some talk of a bolt action, single-shot upper that would allow you to run a .308 on an AR-15 lower...but that isn't what we're talking about.

Also, there are .30 cal cartridges (like the 300 Blackout as one example) that run with a standard AR-15 lower...but that's a far cry from a true .308/7.62x51 round.

Finally, there are new offerings like the Colt 901 modular rifle that offer you both .223/5.56 and .308/7.62 capability in a single rifle with a swap of a couple parts.
 
Re: An Argument

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Skeld1</div><div class="ubbcode-body">A person I know claims that there is a way to run .308's in his AR-15 "just by changing the upper." I don't see how that's possible when a .308 round won't even fit through the mag well of his AR-15 lower, and I tried to tell him this, but he is insistent. If this were the case I'm not sure why anyone would be producing the AR-10/LR-308 guns? No, I'm not trolling, I just need some confirmation from folks who are more knowledgeable with this stuff than myself. </div></div>

I think there was an article in the American Rifleman about a new lower that had this capability.
 
Re: An Argument

Well there goes my train of thought with that avatar...anyway, we were arguing specifically about 7.62X51. The mag well length seems to be the limiting factor, unless single shot as someone mentioned, but in my mind that doesn't really count and I don't think that was what he was talking about.

I didn't know if there was something where the magazine carried the rounds at a steep angle to fit inside the mag well.
 
Re: An Argument

If the angle was steep enough to fit a 7.62x51 there is no way the bolt would catch the back of the round to feed it. Does your friend happen to work in a gunshop? Anything is possible in a gunshop.
 
Re: An Argument

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Skeld1</div><div class="ubbcode-body">A person I know claims that there is a way to run .308's in his AR-15 "just by changing the upper." I don't see how that's possible when a .308 round won't even fit through the mag well of his AR-15 lower, and I tried to tell him this, but he is insistent.</div></div>Maybe he's thinking of 7.62x39... That would work.
 
Re: An Argument

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Exo</div><div class="ubbcode-body">

agreed...i just about sh!t myself when i first saw the youtube of it...i want one!

</div></div>

I was on the colt bandwagon for this for almost a year. Prepaid and waited. And waited. And waited. When the rifles finally shipped they were missing a $20 part. That's right, the adapter block. The word from the csr I hassled at colt is they will be available in a package with a colt 5.56 upper so I have moved on. I still liked the one I played with and maybe later on as the bitter disappointment wears off I will pick one up as a dedicated 308.
 
Re: An Argument

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mm128</div><div class="ubbcode-body">Might WANT to take a look at the NEW Colt Multi Platform rifle. It is a .308 that can interchange a 5.56 upper......


M. </div></div>

I have seen that. The gun in question in our argument is a Bushmaster ORC 5.56.