I kinda want one

http://www.petersenshunting.com/gear-accessories/nemo-omen-458/

2nd that

Somewhere some one was producing uppers for the .308 lowers in .450 Marlin.  Pretty close to a Win Mag!

A little over halfway down the page.

http://www.ar-10-rifles.com/index.php

Weak!  I'd actually prefer a 458 Lott, but that's not nearly as feasible.

the only way to describe this is TENT POLE!

Google .458 Garand...  

I'd seen Schuffs (sp?) 458 Garands a few years ago and they are definitely cool, but I'm really digging the thought of a 458 WM AR.

It has to be pretty big. The 300WM one is huge. But I wouldn't say no.

One powerfull rifle.

Out of curiosity, not being an expert on ballistics, I gotta ask...what does it offer that others can't do?  I read the info on the .458 Win Mag and it said the maximum yardage for use on large animals is 110 yards.  I'm guessing that's probably debatable but it's accepted that it's a short range, big boom type caliber.  So, keeping in mind that there's almost zero chance that an AR based rifle, regardless of caliber, will see the light of day in the land of giant animals, why would someone choose such a big, heavy AR when much lighter options are available in calibers that can also take down rampaging elephants and rogue escaped rhinos such as the .50 Beowulf?  I understand that a .458 Win Mag has more energy but they both are capable of taking giant critters in a hurry so is it the appeal of such big cartridge in an AR or is there something else?

Not an expert here, just isn't adding up to me and other than the obvious coolness, what's the advantage?

Because we can.

500gr Federal Fusion at over 2000fps from 18" barrel, Murica!

LOL, that's a good enough reason on it's own for sure, I'm just curious about the rest of it.

they are not even in the same ball park. the 458 win mag with a 500 grain bullet has as much velocity and energy at 300 yds as the 458 socom or 50 beowulf does at the muzzle also the 500 grain dangerous game bullets will penetrate much deeper than the pistol bullets used for the beowulf and usable rifle bullets for the socom . I agree it might not be the logical choice since the only rhino stampede I have seen here in missouri is when they put fresh mashed potato's and gravy on the food bar at R'yans but it sure would be fun to amaze your friends and family.

It will be interesting to see how the AR10-ish market develops with the big bore and lighter weight guns.  The recoil penalties can be mitigated to an extent, but you really need to design the system around the cartridge and its burn rate characteristics, as well as the feeding challenges from large cases and blunt noses.

That's what I was looking for, thanks!  So basically you could say that they are both capable of dropping huge critters but the .458 Win Mag does it with a lot more power.  I think I would use the much lighter and lighter recoiling AR15 platform for big game in North America but there's no doubt almost every AR nut out there would want a big caliber AR10, I'd buy one (if I could afford it lol).

Not being a ballistics expert as I mentioned earlier, I gotta ask, what is the biggest cartridge realistically possible, in an AR10 platform? Assuming the AR10 platform on a whole, is evolving into the smaller, lighter style like the DPMS Gen II, will that make it easier or more difficult, to produce even larger caliber offerings?

In the AR10 platform. I guess it would be that 308 based .45. I think it's called the 45 raptor. But it's made for pistol diameter bullets, not .458, IIRC.

There's a member here that has an AR-10ish rifle that's just as powerful as a 458 WM, but it's a wildcat cartridge based off of very expensive and hard to find brass and it takes a lot of work to form the brass.  His rifle is the only one in existence.  It's beautiful though. Just Google "470 Rhino"

There's always some new, latest greatest, wildcat cartridge but until they have established a foothold in the market/SAAMI recognition, I don't consider them.  There's nothing in North America that can't be dropped by my .50 Beowulf so I have no need for giant caliber AR10 cartridge for hunting but if there was a biggest, baddest rifle cartridge in the AR10 platform, it would be worth having for the cool factor.

I thought I'd share a new one that Black Hole is developing that should be out in the summer of 2015.  Not a 458 Win Mag but this one does run through an AR10. I believe it will be at thumper deluxe. Full sized RSAUM case necked up to 458. Production magazines are almost finished. Side by side with the Big Boy.



Greg

That's me.  It is another Teppo Jutsu creation that uses modified .500 Jeffrey cases cut, formed, reamed, and rim rebated to 'magnum' size so it uses a RSAUM bolt.  It has a 55K psi limit and launches a 500 gr. .475 bullet to 1900 fps SAFELY.  Not quite the .470 NE we wanted but close enough, and the upper was built for less than $1500 including the Pac-Nor match barrel.
And FYI, I have chonoed my .458 Win mag with factory loads and they rarely got over 1900 fps despite them being claimed to give 2000 fps plus.  Not going to happen with a 22 inch barrel anyway, at least not my barrel.  Handloads can go 2000 fps with a 500 gr. and then some, but no factory loads I have ever chronoed would.  


Left to Right:
.416 Rigby, .458 Win Mag, .470 Rhino, .308, .458 SOCOM, 5.56.

Let me tell you a story.

When I was a young boy my father went shooting with some buddies. One of them had a brand new Winchester M70 Safari Express in .458 Win Mag. It had just been topped off with a 2x fixed scope. On the first shot the shooter took the scope to his eye socket with so much force the optics were broken. So was his face. He sold it to my dad on the spot. And thus began my great adventure with THE HAMMER OF THOR. (sans optic)

I spent my teenage years hard casting 500gr swaged gas-checks. Even light loads required a double-throw from our largest powder measure to reach the desired charge weight. I would then take THE HAMMER OF THOR out on the desert with friends. We would set up a "tumbler" which is what we called the bushel-basket size lava boulders scattered around the area. With one shot THE HAMMER OF THOR would reduce them to rubble.  Steel truck wheels? Clean holes like they were die-punched. We even shot a dead steer once. End-to-end. In all the times I took someone out shooting NOBODY ever shot it despite many promises of "I will shoot it, but you shoot it first." Everybody went back on that promise.  And I stood like Mogli, boy-master of the jungle. And it was good.

So, to answer your question "What can it do?" Well, for a teenage boy it can stand as the phalic representation of his Alpha status among his peers. lol

I definitely want one of these.

The one on the left is a .458 Win mag that is coming out and the source of this thread and the one on the right is also a new cartridge that is soon to come out right?

THAT is beautiful!!

Couldn't bring it to Africa, that's the shame for a rifle like that

I get a lot of "are you crazy?? Why would you want to shoot that!!", because I guess it's unusual for a female with pink gear and guns to be at the range shooting a .357 magnum derringer, a S&W 629 V-Comp .44 magnum and a .50 Beowulf lol.  I can't count how many guys I've offered the opportunity to shoot the little magnum derringer, the 629 and the Beowulf and to this day I haven't had a single one accept.  They all say "no thanks, I'm not shooting that thing, you are one crazy chick" lol.  Now, those guns are probably pretty tame to what you're referring to but they are scary to folks who aren't used to them I guess.  I like shooting "thumpers" but I've never shot any of the big "safari" caliber rifles so my love of thumpers may not go that far lol.  

That is correct. The Win Mag is there for comparison.  The wildcat is the one we are working on.

Greg

How close will this sucker be to 458 WM and any possibility of other calibers on this case to make some serious thudders...

Just wish Marty could have gotten the Rhino Series off the ground....

According to the guys doing the most on it the performance is pretty close. Obviously it won't be as stout but it'll leave a hurt on both ends. Yes there is a potential for other chambering choices.  That's already started. Nothing worse than a guy with idle time, bushing dies and a barrel maker that likes inovation.

Greg

If Nemo is manufacturing an Omen in .458 Win Mag, is that going to pretty much take the lion's share of sales compared to a wildcat cartridge that is designed to come close to the .458WM?

If a fellow wants the  full blown 458 he'll go for the NEMO with accompanying costs of toatal proprietery uppers and lowers.  If he wants to just buy a bolt, barrel and magazines and ge tthe job done then he will go wildcat. That being said the wildcat in this case would proably be more attractive to many simply becuase of the . High volume shooters probably won't get either one as they just aren't mag dump size rounds.  I think at $6,000 or so the NEMO will be a neat rilfe but I'll have to settle for my new upper that will set me back maybe $1.000 as us retired guys aren't quite that flush with extra income.

Wildcats fill a niche that shooters identify and sometimes let hem get the performance they want with less cost. In reality there is proably a factory SAAMI round out there that will do anything a wildcat will do but it maynot fit the action we have or be almost impossible to find. A set of dies, some ingenuity and some time at the relaoding bench often pays off in spades as in the 6X6.8 and the American 30.  

Greg

That makes sense, I hadn't considered the price difference.

The .450 Marlin has been chambered in AR-10s....
1950/2000fps with a 405gr bullet.  

Load them with the hornady 350gr  or maybe a Barnes spire point, or Hornady?  I had a Marline Guide Gun so did not pay attention to the Spire points.


.44cal has a lot of potential.  Got all the Silhouette pistol bullets and the .444 Marlin bullets, plus Buffalo Bore etc bear defense loads using 300gr hardcast and most all for handguns...

.450 marlin case from Hornady has a larger than standard belt.  Would be easy to taper it down to .429
Do a bottleneck case from the .450m down to .338, .358, or even .375.  I am not a 416 afficionado, but got 400gr bullets there for African game...

Sure as hell don't need a large magnum receiver for big results.  Like an Accuracy Intl or Sako TRG-42 in .338 Lapua isn't fast enough for 1500yd target engagement?  What about a Barrett semi in .50BMG?  A bit less money for the Barrett and a 750gr match projectile no other ctg can touch..  In production and proven for almost 100yrs....

For a crew-served weapon maybe a semi-auto .338 Lapua or .375 Chey-Tac fills a niche?

In AR-10 world you got Short Action Utra Mag, Win Short Mag, all things .284win,, and the short belted mags like .458 American and .450 Marlin.
If the boltface can be opened up past .535, maybe the short Lazzeroni ctgs like Patriot.

Spend some time studying the Sierra Ballistics software.  When a 77gr Matchking at 2700fps hits with more energy at 500yds than a Factory 158gr .357mag from 8-3/8" barrel does at 25yds, the case is made for Ballistic effectiveness and huge diameters and hot velocity mean nothing.  

A .338/284 with 250gr matdhking is an awesome ballistic package.  .338saum or wsm even moreso...

I have a 458 win mag. I much prefer its recoil to my 340 weatherby. It is a fine cartridge.