View Full Version : what calibers come in the "15" platform?

July 20, 2012, 05:00 PM
i was thinking about a .243 or a .270 but when i looked them up it said i need a AR-10 lower? then what other rifle rounds can i use besides like the .416 Barrett, 6.5 Grendal, .50 Beowolf? i was wanting a long range alternative.

July 20, 2012, 05:05 PM
Long range "what"...
Steel/paper? or game?
If game, specific....
What is long range to you...(?)

Optimal selection depends on the specifics...

July 20, 2012, 05:13 PM
to me its 500+ yards. an yes game if possible. me an the future wife -.- lol wants to move to Alaska eventually so it will be in that kind of climate.

July 20, 2012, 05:35 PM

Your selection is also very dependent on whether you handload, or use commercial ammo...
And if you use commercial, how much do you intend to shoot- and how substantial is your budget?

You still need to narrow down the game...
There's a huge difference between bear and elk, and whitetail and varmints...

We shoot steel at long range, have built one in 6.5 Grendel and am starting another. The 6.8 SPC is getting some better BC bullets for long range as well.

July 20, 2012, 06:06 PM
i was wanting a long range alternative.

Well... there's always the Nemo Omen in 300 or 338 WM. Retail: $3,252... without the Huskemaw scope. :rolleyes:



July 20, 2012, 06:12 PM
i take it with the kind of game in Alaska im going to be looking at more Energy then Velocity?

July 20, 2012, 07:15 PM
Grendel or 6.8 is probably your best bet for long range in a AR-15 receiver

July 20, 2012, 07:54 PM
i take it for energy i would need to look at the .50 beowulf?

July 20, 2012, 09:27 PM
.50 Beo, .458 SOCOM, .450 Bushmaster...

Keep in mind these are all "short range" cartridges.

There's only so much you can get out of the AR-15 platform.

If you want to push big bullets fast, you need case capacity, period.

Then you're into the AR-10 platform...or even an M1A...

Why are you set on a semi?

Sounds to me that your needs, and budget, would be better suited to a bolt action.

Deja vu
July 20, 2012, 09:31 PM
I can attest to the power of the 458 Socom. It uses the same bullets as the 45/70 and in the lighter bullets will push them at nearly the same speed as the marlin 45/70 load (much hotter than factory) Where the marlin 45/70 loads tent to win over the 458 is in the heavier bullets. the 458 does not have the case capacity to push the 450+ grain bullets as hard as the marlin.

July 21, 2012, 06:36 AM
im set on a semi since my job doesn't pay enuf $$$ to go buy what i need when i need it an since i already have this platform all i would need would be a new upper. i was loooking at the .50 beuwolf, an that .458 socom. an the largest besides Moose i think is there kodak bear.

July 21, 2012, 07:28 AM
if i did the 6.5 grendel what all do i need just a upper?

July 21, 2012, 09:54 AM
...matched with a bolt and a single stack magazine. ;) -7-

July 21, 2012, 12:16 PM
You don't necessarily need an entire new upper, just makes it faster/easier to swap out calibers.

New barrel with headspaced bolt as mentioned, and magazine(s)....

I don't hunt....but I would suspect that with 140 grains being the very upper limit of what the 6.5 Grendel can handle, that you'd be undergunned for big game.

July 21, 2012, 01:20 PM
well let me see if I can list them all.
221 fireball
222 remington
223/5.56(a very good long range round but not that great if you want it for 300+ yard kill shots)
223 wylde(an intermediary between 223 and 5.56, compatible with both but somehow is supposed to have superior ballistics)
6x45MM(a wildcat round that mostly disappeared after the introduction of the 6.5 and 6.8)
6.5 grendel
6.8SPC(from my understanding the 6.8 surpasses the 6.5 over range)
7.62x25 tokarev
300 fireball
300 whisper
300 blackout
338(don't recall the name but it's basically a 6.8SPC cartridge necked up to 338)
450 bushmaster
458 socom
50 beowolf.
for the most part your 5.56 and 6.8 are probably your best bet for long range shooting as long as you are putting it on paper. otherwise an AR10 in 243 is about as good as you can get for long range.

July 21, 2012, 04:06 PM
CZ makes - not for import - 7.5x55 Swiss and 6.5x55 Swede.

July 21, 2012, 05:13 PM
he wants a rifle that has 500+ yard range, and the energy for alaskan big game, because of that i cannot recommend anything available in the AR15 platform and the larger AR10 platform is a must... seems like all the big game in alaska will try to kill you, especially moose

July 21, 2012, 06:43 PM
I agree with jason. for alaskan game there really is nothing in either the 15 or 10 platform ARs. 458 socom or 450 bushmaster are only going to be able to drop moose and kodiak within 200 yards. past that they lose to much energy. you would be better off buying a cheap bolt action like the ruger american, weatherby vanguard or bottom barrel remington 700 ADL in 300 win mag or 300 weatherby mag. sure a 308 can hit a moose at 500 yards but the energy it has left once it gets there is just too little.

July 22, 2012, 06:10 AM
when i went to the gunsmith he did suggest that .450 bushmaster. does that upper fit on a 15 or does it go on the 10? an if i had to choose between long range or the kinetic energy i would go with the energy over range.

July 22, 2012, 10:21 AM
500+ yards. The 6.5G/264LBC w/ an 18+" barrel would be nice for paper & steel.
Although. the 6.8 goes have the 140gr SSA/Berger ammo. Also, there are some Olympic Arms custom calibers that work in the AR 15 platform.

July 22, 2012, 10:29 AM
the 450 bushmaster is an AR15 chambering but again, you'll have to limit yourself on those long range shots, it probably wont do you much good past 200 yards.

July 22, 2012, 10:42 AM
Here's my take...
You say you want to use your 15 lower, because you have it...
I get that...

But, your two "new" intended uses- will require two different calibers. Long range target, and short range bear/moose/elk, just aren't packaged in the same caliber from that platform.

So, get two new uppers, or just barrels/bolts/mags and change out as needed.

Or, what I would do...

Forget about the AR for these, and get yourself a bolt gun that will (A) generally be more accurate for long range, and (B) take any game on the continent.
Something along the lines of the .300WSM....(just one of many that will "work")

You'll end up spending less, and not compromising by trying to get more out of the 15 platform than it was designed for.

July 22, 2012, 10:42 AM
ok so i would be a lil less for the longer range if i am able to use the .450 bushy on moose an bear.

July 24, 2012, 01:29 PM
You're going to spend as much-or more- on a .450 Bushmaster upper as you would for a brandy-new .30 cal (or larger) bolt gun...

The ammo is going to be more expensive at $25-$30 box...and there's no "cheap" practice/plinking ammo I know of...

And, the bolt gun will give you the long range aspect back.

Suggest you price .450 uppers and consider accordingly...

Good luck.

July 24, 2012, 02:05 PM
The ammo is going to be more expensive at $25-$30 box...and there's no "cheap" practice/plinking ammo I know of...
reloading components aren't even cheap.

August 25, 2012, 01:31 PM
I can reload my 458 Socom rounds with Hornady 300 grain JHP's for 57 cents a piece, powder and primer included. Only two types of folks own the big bore AR's, those that reload and rich guys. Big Bore AR ammo can be hard to find and expensive but reloading does help tremendously.

August 25, 2012, 09:34 PM
if youre looking for a practical upgrade from 5.56mm, your choices are really either the 6.5mm grendel or 6.8mm SPC.. of which to go for its hard to say, a lot of facts to decide, im trying to decide on this one myself, but narrowed it down to one of these two

August 26, 2012, 01:23 PM
Olympic makes the AR15 in 22-250.

If you want something bigger for longer ranges you'll probably have to go to an AR-10 platform. But others have posted enough about it.


August 26, 2012, 02:36 PM
how can they make a .22-250 for the AR15?... unless you use really short bullets for it, COAL of the .22-250 is 2.35", i dont think a standard .22-250 round would fit?

August 28, 2012, 10:14 PM
Olympic arms makes the UMAR in .22-250. http://youtu.be/2JggV5tZXOM
From the Vegas Shot Show.

The Olympic Arms sites is down for maint. or I'd post a link for the site.

August 31, 2012, 01:13 AM
As said before for hunting past 200 yds. in the AR 15 platform you are best to go with either the 6.5 or 6.8. If it was me I would go with the 6.8 and re-load.