What caliber uppers will fit my current .223 AR-15 lower?

[shaftbass]

The gun in question is a Bushmaster AR-15 E2S. I have wanted to buy a different upper instead of buying an entirely new gun, but I'm not sure what caliber choices I have. Whatever it is, it will be a 20"+ heavy type barrel more for long range (300 yard+) accuracy than anything. I will decide which caliber I want to use for this after I know which ones are available.

Thanks for any info.

[dralarms]

I know anything 6.8SPC and below will fit, not sure about any of the other sizes. I know 308 takes an Ar-10 lower

[Rightwinger]

.20 Tactical, .204 Ruger, 6.5 Grendel, 6.8 SPC, 458 Socom would be the main ones and easiest to obtain. Some will require a different magazine to run but the .204 Ruger and 458 Socom are replace and shoot.

There are others that I have glanced at but some are probably for the .308 sized lowers. 6.5 Creedmore, .243 etc. There is something out there for you though. I currently only have the .458 Socom as an alternate caliber but have owned the .204 (fantastic shooting) and a 6.8 SPC.

[Guest Abominable_Hillbilly]

There are wildcats available chambered in the newer short magnums. I had been looking at one in .25WSSM. Oly was even making one.

[shaftbass]

Thanks for the info. Time to research a few new to me calibers.

[TGO David]

5.45 x 39.

[Guest Glknknox]

Get a Beowulf (.50) and a small bag of ice for your shoulder.

They use the same mags as the .223, all you have to do is replace the upper.

(j/k about the ice thing)

[molonlabetn]

They make .50bmg single-shot uppers, too...

Pretty much any caliber you can think of has been made to fit and function in an AR.

6.5 Grendel, .243 WSSM, and .25 WSSM would probably be the best options, since the really big calibers such as .45 Bushmaster, .458 Socom, and .50 Beowulf won't shoot flat enough to be good long-range choices... and anything less would put you in the same category as the .223 you already have.

[G27]

Olympic even makes a .40S&W upper that accepts Glock mags!

Not that I'd spend that when I already have my toy Sub2k...

[Magiccarpetrides]

Olympic even makes a .40S&W upper that accepts Glock mags!

Not that I'd spend that when I already have my toy Sub2k...

Too bad they dont make a 9mm upper that does(accept glock mags)!

[dcloudy777]

All the advice given so far is accurate and good stuff. That being said, I think you might be best served with sticking with .223. If you pick a good barrel with a fast twist rate (1:8, 1:7, etc.), the heavier weight .223 rounds are capable of phenomenal accuracy out to 600m. .223 from the AR platform pretty much dominates NRA High-Power, which shoots out to 600. And you have the advantages of being able to use much cheaper plinking fodder for practice, and not having to worry about bolt or magazine interchangability. Of course, you may just want to change calibers just to have something different, which is always encouraged.

DanO

[DaveTN]

The .308 will do what you want (long range accuracy). I think if you compare ammo cost between it and the designer calibers you will find that if you shoot much you can just buy a .308 AR and call it a day.

Then you have both rifles in either caliber.

[shaftbass]

The .308 will do what you want (long range accuracy). I think if you compare ammo cost between it and the designer calibers you will find that if you shoot much you can just buy a .308 AR and call it a day.

Then you have both rifles in either caliber.

I've considered that too

Thanks for all the info guys.

[Guest JLowe]

I got a buddy who shoots one of those 6mm's in NRA 1000yrd matches and wins. The only problem, you have reload them. If your looking for a different round to shoot go with the 6.8 lots of people are making ammo and its easier to get these days. It accurate and give you more punch at longer ranges.