Most powerful cartridges for ARs?

[Oolong]

Just wanted to know what are the highest power cartridges the AR-10 and 15 are chambered in respectively?

 

[JohnBiltz]

.50 Beowulf probably in an AR 15. It compares favorably with 45/70. No idea in an AR 10.

 

[General Geoff]

.50BMG uppers exist for the AR15, though they're single shot deals.

 

[EchoM70]

The Nemo Omen is a .300 Win Mag AR-10 style Rifle. AR-15 would. Probably be .50 Beowulf.

 

[Panzerschwein]

.50 Bey or SOCOM.

 

[Oolong]

Is the nemo omen really a ar 10 or just in the shape of a ar 10? Could I take it'a upper and feed it'a mag through a generic ar 10 lower?

 

[savanahsdad]

25WSSM or the 30 Ossm in the AR15 the 25WSSM is like having a 25-06 in a short fat case

 

[LoonWulf]

In the 15, the Wssm bassed rounds or similar, which use larger barrel extension, bolts, and mostly modified carriers.
For stuff that uses modified but still common size parts the .450 bushy, .458 socom, and 50 Bwulf are all pretty similar in terms of bullet weight and velocity. Personally I prefer the Socom

Standard ar10s Im not sure, the .460 raptor delivers a pretty good whallop, but you could probably cram something punchier in also. Then you got the Magnum Ars like the NEMOs....i dont think they count in this discussion tho lol.

 

[MistWolf]

The most powerful caliber I've seen in a 308 frame AR was the 300 Remington Short Ultra Magnum

 

[redneck2]

I have an AR in .358 WSSM. I suspect it is the max you're gonna get. 200 grains at maybe +/-2,800 fps. Feeds thru a standard size mag and lower. The case fills the mag side to side. Stubby bullets load to mag length

I had a .458 SOCOM. This shots a LOT flatter

 

[69Precision]

25WSSM or the 30 Ossm in the AR15 the 25WSSM is like having a 25-06 in a short fat case

Really sad the 25 wssm didn't catch on, optimum AR deer round in my opinion.

 

[Varminterror]

Is the nemo omen really a ar 10 or just in the shape of a ar 10? Could I take it'a upper and feed it'a mag through a generic ar 10 lower?

The Nemo Omen Upper, lower, bolt, bolt carrier, handguard, and gas system are 100% proprietary. Uses standard buffer tube, stock, grips, fire control group, but that's about it...

 

[1stmarine]

I like things that are simple or at least not too complicated or expensive.

AR15 - no need for complex formulas nor expensive rifles.
Easy standard, out of the box... 6.8SPCII 95gr TTSX @ 2850fps from 18" barrels.
Easy reload, economical, from 223R brass. Standard mags and bolts.... 6x45L, 6mm TCU, 25x45 TCU. 80gr-100gr @ 2,600-3000fps.
Big Game, Single stack, brush rounds.... 458 Socom, 50 Beowulf. 250-400gr @ 1600-2100fps
Big Game Cat, double stack full magazines, flatter shooter, more energy... 35 Gunner. 200gr @ 2360fps. 220gr @2200fps
Long range: 6mmBR and 6.5mmBR. Simple rounds, only limited by the availability of high pressure custom bolts. 105gr-123gr @2800-3000fps.
Another simple great long range... 6mm derived from 6.5 LBC/Grendel. 105gr @ 2900fps.

SR25/DPMS/AR10 - No need for complex case donors, custom bolts nor expensive rifles.
Easiest is 308W high performance ammunition for big game (buffalo bore, grizzly, etc..) Sometimes underestimated the power of the 308 alone when loaded full power.
Another super easy 358 Winchester for big game from high performance ammunition like Buffalo bore. The most powerful round for a 308w derivate for the average hunting range.
Easy big game cats: 358-284 and 375-284. Massive power. Equivalent to Whelen ballistics to take down anything walking on this planet including in Africa.
Long range: 7mm-08 - Best long range cartridge from a simple 308 case as a donor. Some bullets might need a gated magazine that is simple.

 

[tarosean]

Is the nemo omen really a ar 10 or just in the shape of a ar 10? Could I take it'a upper and feed it'a mag through a generic ar 10 lower?

You can ask that about any AR10 as they are based on either 1-2 systems or completely proprietary

 

[ColoradoMinuteMan]

Just wanted to know what are the highest power cartridges the AR-10 and 15 are chambered in respectively?

It really depends on what you mean by the term "highest power." Is that most energy at a certain distance, longest range, etc? The amount of velocity or energy a projectile has is a transient thing related to several factors including range. In particular something like 50 Beowulf has a very short lived energy advantage and never has a velocity advantage (see graphs).



Unless you're a boutique cartridge aficionado it's my opinion that sticking to some fairly common cartridges makes sense.

For an AR-15 type platform, if you can't do it with 5.56x45, .300 AAC, 6.8 SPCII, 6.5 Grendel, you might want to ask yourself if you've chosen the right tool for the job.

For an AR-10 type platform, if you can't do it with .308 WIn, 7mm08, .243 Win or 6.5 Creedmoor, you may want to agin ask yourself the same question.

 

[1stmarine]

@ColoradoMinuteMan
I have used those AR15 calibers and decided I needed something better. Something with more killing power but w/o the extra bulk or weight. That is the main reason behind the 35 gunner.
In terms of hunting, the energy alone might give an indication but it doesn't determine the killing potential of a round. Momentum (not energy, two different things) is more important but specially
the terminal design and speed on the target for that given design including the frontal section.
In the northern woods and thick forests, at the avarage distances, larger & heavier calibers have a huge advantage, so many calibers in 35 caliber with 180grs and above
are well known for being fast killers where light for caliber & small bore are not suitable nor the best choice. At the same time 458 and 50 caliber might be too much in terms of ballistics performance
but for sure many people are going to lean towards proven hunting calibers.
Anything below 6.5mm and below is not going to be very versatile. On the AR15 smaller calibers also discard the lightest 30 caliber bullets moving at slow speeds.
For the AR10 the killing power of the 358 winchester is unquestionable including the largest animals. Not that I suggest to hunt a large bear with an AR but in terms of the round potential there
are many benefits not possible with the 30 caliber rounds. This for the same reasons the whelen also has an amazing reputation as fast killer.
No "internet" killers but real life, real deal rounds at the ranges 99% of the folks hunt.

 

[1stmarine]

I should open a new thread for the 35 cal but anyway, from all the wildcats I developed over the years the Gunner has been one of the most fun and rewarding...

180gr TTSX. 2500fps from 16" barrel.

Full stack magazines with either rifle or popular pistol bullets.

It looses little velocity from 10" barrels too...

180gr clocks at 2,350fps from 10" barrel.

200gr Accubond - 2,380 fps - 16" barrel

This is what the accubond looks like in a mil-dot scope. Too much round for deer so I am saving these for larger game like moose, bears or hard to kill large hogs.

I include the power factor that is a momentum value vs. the ft-lb energy that can be misleading. Specially values at the muzzle that mean nothing.

 

[ColoradoMinuteMan]

My reply imbedded in your quoted message.

1stmarine

@ColoradoMinuteMan
I have used those AR15 calibers and decided I needed something better. Something with more killing power but w/o the extra bulk or weight. That is the main reason behind the 35 gunner.

CMM: Fair enough, and I'm all for as many commercial options and wildcats as possible. This is 'Murica baby! However, let's be fair about the situation, did you really design it because you truly couldn't find any cartridge that would do the job, or was it because you were trying to squeeze every last bit of the performance you wanted and wanted to challenge yourself in producing it?

In terms of hunting, the energy alone might give an indication but it doesn't determine the killing potential of a round. Momentum (not energy, two different things) is more important but specially
the terminal design and speed on the target for that given design including the frontal section.
In the northern woods and thick forests, at the avarage distances, larger & heavier calibers have a huge advantage, so many calibers in 35 caliber with 180grs and above
are well known for being fast killers where light for caliber & small bore are not suitable nor the best choice.

CMM: To clarify, I don't think I said that energy was the leading indicating factor, I simply asked, by what measure is the OP determining "most powerful" and I provided velocity and energy as examples of potential objective measures, because those measures are usually easy to ascertain since most ballistic calculators are out-of-the-box equip to produce those figures. Interesting the you mention momentum because momentum and kinetic energy have nearly identical properties when related to linear motion so, I guess I'd need more explanation on why momentum is the appropriate benchmark but kinetic energy is not.

At the same time 458 and 50 caliber might be too much in terms of ballistics performance
but for sure many people are going to lean towards proven hunting calibers.
Anything below 6.5mm and below is not going to be very versatile.

CMM: I'll have to agree to disagree on this one. .223 can not only kill but also do so without destroying all the meat on anything from a squirrel to a deer. It can also target shoot out past 500 yards, be used for defense or combat against humans. I find that fairly versatile.

On the AR15 smaller calibers also discard the lightest 30 caliber bullets moving at slow speeds.
For the AR10 the killing power of the 358 winchester is unquestionable including the largest animals. Not that I suggest to hunt a large bear with an AR but in terms of the round potential there
are many benefits not possible with the 30 caliber rounds. This for the same reasons the whelen also has an amazing reputation as fast killer.
No "internet" killers but real life, real deal rounds at the ranges 99% of the folks hunt.

CMM: I don't doubt the killing power of a .358 Win, but I will challenge that it is far superior to the .308 Win. The .308 will kill anything that walks on land. Plenty of black and brown bears are killed with the .308. In fact plenty of documented kills of black bears with .300 AAC. Bullet construction, velocity, mass, sectional density, and shot placement are all going to be contributing factors to how much vital tissue damage occurs. Ultimately vital tissue damage is what kills.

So, all of this wasn't meant to say the .308 is the most powerful cartridge available or that nobody needs anything more powerful than a .308. My point above, which I'll reiterate, is that if you need something more powerful than a .308. My original point it, outside of boutique cartridge aficionados, like yourself, it seems smart to just stick with what is more commonly available. If you are really in need of something the a .308 cannot accomplish, then really the AR-10 patterned rifle are not the best fit. They are already fairly heavy for caliber and packing more onto the platform seems like a square peg in a round hole.

 

[Varminterror]

You can ask that about any AR10 as they are based on either 1-2 systems or completely proprietary

Except that in AR-10 and LR-308 platforms, the designs are broadly out licensed, so there are many folks making parts for both. Sure, the two are non-interchangeable, but there are multiple manufacturers using both standards. If I want a barrel for either, I can get it from a lot of different makers, and really only have to be sure my brand X upper matches my brand Y lower.

The same cannot be said for the Nemo Omen. Nemo is the only company making any of their parts, so it's purely proprietary, with no current out licensing.

 

[1stmarine]

My reply imbedded in your quoted message.

1stmarine

CMM,
The idea here has been to have the killing power of large bores with heavy grain with superior ballistics in the AR15.

CMM: Fair enough, and I'm all for as many commercial options and wildcats as possible. This is 'Murica baby! However, let's be fair about the situation, did you really design it because you truly couldn't find any cartridge that would do the job, or was it because you were trying to squeeze every last bit of the performance you wanted and wanted to challenge yourself in producing it?

I have quite a few calibers already but I wanted something in the smaller AR15 to improve trajectories and range/power of the beowolf but w/o sacrificing on a reliable killer no matter
what the situation. I could not find a caliber with the trajectory and power easy to own and reload w/o being expensive nor complicated. I mean aside from designing and testing a new
wildcat that it can be a fun project.

CMM: To clarify, I don't think I said that energy was the leading indicating factor, I simply asked, by what measure is the OP determining "most powerful" and I provided velocity and energy as examples of potential objective measures, because those measures are usually easy to ascertain since most ballistic calculators are out-of-the-box equip to produce those figures. Interesting the you mention momentum because momentum and kinetic energy have nearly identical properties when related to linear motion so, I guess I'd need more explanation on why momentum is the appropriate benchmark but kinetic energy is not.

I understand. I Iike what you did with the graphics because any values at the muzzle are meaningless and this way it really shows how things develop downrange.
Still I wanted to make clear about momentum that is what knocks things down and carries through with the added frontal section and whatever terminal design.
Kinetic energy is an indicator but futile. That is why power factor (momentum) has been introduced as a more meaningful way to understand power on a target.

CMM: I'll have to agree to disagree on this one. .223 can not only kill but also do so without destroying all the meat on anything from a squirrel to a deer. It can also target shoot out past 500 yards, be used for defense or combat against humans. I find that fairly versatile.

I agree the 223 is a very effective and handy round. But limited and not suitable for heavier game. 60-80gr specialty loads perform amazingly well often overlooked or misunderstood.
But once one gets to the 6mm the hunting assortment of bullets pretty much continues and expands where the 223 stops. Also easy to make options form 223 cases here.
I understand the 35 is perhaps too much even for deer but there are pretty suitable bullets and never heard of anyone complaining of plenty of killing potential, specially in small packages.

CMM: I don't doubt the killing power of a .358 Win, but I will challenge that it is far superior to the .308 Win. The .308 will kill anything that walks on land. Plenty of black and brown bears are killed with the .308. In fact plenty of documented kills of black bears with .300 AAC. Bullet construction, velocity, mass, sectional density, and shot placement are all going to be contributing factors to how much vital tissue damage occurs. Ultimately vital tissue damage is what kills.

The killing doesn't come from wounding potential only but good killing comes from inflicting massive shock and many times CNS disruption (short circuit the brain). That is what ethical hunters look for.
The 308w is an amazing killer with premium bullets like 180gr bonded for large game. It has taken large Grizly bears with one shot. I think the issue is when hunting with carbines and auto-loaders like 16" it looses some vital speed and also like the 30-06 is not ideal for brush hunting. Still substantial deflection when hitting vegetation and small branches. This is where the 35 and 375 calibers show a significant improvement also in broader more massive wounding although penetration might be similar. These larger calibers are considered by many true hunters due to their track record as fast killers. Even with the modest 35 Remington.
As far as the 300 whisper killing bears ...I guess poachers are also successful with inexpensive 22LR and 9mm. Following your line of though from the first paragraph, are people hunting with the whisper because they cannot
afford a more suitable round or for the challenge even at the risk of making an animal suffer unnecessarily? I am saying this because even a 357 magnum with premium hunting bullets is a popular, affordable yet more powerful round for that animal.

So, all of this wasn't meant to say the .308 is the most powerful cartridge available or that nobody needs anything more powerful than a .308. My point above, which I'll reiterate, is that if you need something more powerful than a .308. My original point it, outside of boutique cartridge aficionados, like yourself, it seems smart to just stick with what is more commonly available. If you are really in need of something the a .308 cannot accomplish, then really the AR-10 patterned rifle are not the best fit. They are already fairly heavy for caliber and packing more onto the platform seems like a square peg in a round hole.

I understand. I would recommend the 308 to many people but since the thread is about options with more power I started talking about other alternatives.
There is no doubt the 308 is an amazing meat producing machine but what I want to say is that all other things being equal, for extra power from moderate barrels the 358 gives more killing power
with little investment even using the same 308w brass as donor. Very simple to make and own. We are talking about proven fast killers no matter the situation, including brush country.

Regarding the AR15 and 35 caliber gunner idea...

With the Ar15 obvious limitations calibers above 7mm are not that efficient anymore until you get to the 35 caliber.
You have a lot of good hunting bullets in 30, 338 and 8mm but they are too long for the platform.
IMO the 35 and 375 are the two last calibers that provide heavy grain, with modest length on bullets yet still pretty decent ballistic performance.
After 35 and 375 ballistic performance drops substantially. I mean, you still have a limited selection
of heavy 416 and obviously 50 caliber but those are designed for larger super-magnum and military cases.
The good thing about the 458 and 50 BEO is the amazing killing potential at moderate ranges.

In short, the drivers for me has always been very clear:
-Simplicity - Full stack, common components, nothing expensive or exclusive.
-Versatility - Can use anything from 125gr pistol bullets to 220gr and even 250gr spitzer.
In a 16" carbine I have more killing power than the 308 from the same size barrel but in a lighter rifle. Also a better performer in short barrels and 10" pistols.
-Decent trajectories - Trajectories are pretty friendly unlike slower moving calibers and shotgun like ballistics. Still pretty adequate brush round. Another role where the 30 calibers come short.
-Lots of momentum and killing power - It puts lots of momentum at 300 yards with authority ahead of the others.

I also like the fact that is shooting great with 140gr-200gr fmj/tmj pistol bullets that make practice more economical than the 308. Can also hunt predators with those if I want.

Of course I could have gone with a WSM case but the added complexity vs. the gain difference didn't pay off.

Whatever the choices we always shave a trade off.

 

[ColoradoMinuteMan]

Thanks for the reply 1stmarine. There is a lot of what you said that I agree with and makes sense to me. There are a few points though that I'd like to explore more.

The killing doesn't come from wounding potential only but good killing comes from inflicting massive shock and many times CNS disruption (short circuit the brain). That is what ethical hunters look for.

I agree that hydrostatic shock can cause neural damage, incapacitate and cause death. However, the primary means of killing medium and large sized game is by targeting vital tissue. By penetrating and causing massive tissue damage to the heart and lungs you quickly starve the brain of oxygen which will the incapacitate and likely quickly kill the animal. Most ethical hunting from pigs to bears will target the lungs and heart. This is why bow hunters can also inflict an ethical kill even though they are not producing enough energy to induce hydrostatic shock. They too target the vital tissue which will stop oxygen from reaching the brain. Most of the ethical hunting instruction that I have participated in does not recommend targeting the central nervous system of medium to large animals although, I have seen some who will advocate spinal shots just behind the animals head. That's not my preference due to the small target area.

So, taking this back to the broader discussion, if you have a vital hit with a properly constructed .358 or .308 projectile, I just don't see it making a difference one way or another to how dead the animal is or how quickly it dies. Perhaps on a hippopotamus or an elephant that has significantly larger lungs and heart and requires additional tissue damage to allow it to quickly suffocate, but nothing in North America will tell much difference between a .358 and .308, all other things remaining equal.

I'd also like to understand more about .357 being better for black bear hunting than .300 AAC. I admittedly haven't done a lot of comparison between the two but my instincts tell me that the .300 AAC would perform well when compared to a .357 considering it has twice the muzzle velocity as the .357 and a better ballistic coefficient to maintain velocity at distance. A well constructed bullet would have deep penetration if shot within .357 ranges and induce significant vital tissue damage.

 

[JohnMc]

Really sad the 25 wssm didn't catch on, optimum AR deer round in my opinion.

Agreed, though it's more that Winchester didn't want to pay future patent royalties on new guns after they lost. IIRC, they paid what the court said they owed and then dropped rifle production. Olin curtailed ammo production after that.

 

[Tirod]

No "internet" killers but real life, real deal rounds at the ranges 99% of the folks hunt.

I find this to be too vague.

What I choose to use hunting whitetail in dense broken Ozark woodlands won't do for someone hunting mule deer or elk in Colorado. And a cartridge that can do both isn't well suited for either. That is why there are different cartridges - they meet the differing range and targeting needs that exist.

A bullet meant to travel out 250m and then penetrate at least 12 - 18 inches thru the chest cavity and vitals of a large 800 pound animal will be a lot different than one meant to travel no more than 45m - almost pistol range. Trying to narrow down what are "the ranges 99% folks hunt" could mean the maximum 80 to 120 meters most deer hunters actually shoot - not claim they do. Lopping off 100 meters from the expected range has a significant impact on what the bullet is required to do.

That "99%" is simply too big a variable. Case in point, MO offers a pistol season running right now, I use an AR pistol with 10.5" barrel using 70 grain OTM bullets and don't expect a shot over 80m. That will still deliver enough force to put down a deer given proper shot placement. Having mapped the shots I personally have seen or encountered in these woods, most were taken under 50m because that is as far as you can see thru the trees. Lots of MO hunters are adopting the AR pistol to use in this season. I also use it in rifle season now - just because the longer guns are legal doesn't mean the conditions have changed any. Therefore I don't see the need to carry a gun that weighs two pounds more or has triple the recoil.

Range to the target has a tremendous influence on what cartridge to choose and not specifying it means there won't be any one cartridge "better" suited than another. A "99%" coverage will bias the conversation to use only the biggest longest ranging cartridge and that means adopting the maximum power and recoil the gun and shooter can tolerate. Yet at least 50% of those shots, and likely far more, will be taken at much shorter ranges.

It is exactly the reason that .30 caliber battle rifles were made obsolete - close examination of what was happening showed they were counterproductive to accuracy, the amount of ammo carried, and the ranges of engagement that were really being used.

Absent a maximum range and the size of the game intended there won't be a well grounded answer. A 99% solution encompasses elk shot at over 450 meters with sub 7mm cartridges, or small game taken with .50 bullets at under 50 feet.

As for attempting to fit the biggest bore bullet, the results are usually counterproductive. The larger the bore the slower the bullet in general, and the more bullet drop that you deal with. That's why after the .450 cartridges for the AR15 have been developed there is now a trend for the .35 and .375. A comparison of the .458 SOCOM and .375 SOCOM is interesting, it lengthens the range for the same bullet drop at least 100m and still delivers most the foot pounds of force. Aerodynamic efficiency has its benefits.

 

[1stmarine]

CMM,
When I say massive shock I didn't mean to imply aiming for the spinal cord and abandon the typical shots. Let me explain...
There is much more to be discussed here based on the type of animal, weight of the animal, angle and other conditions but initially there
is no need to go for the neck unless there are doubts about a safer shot.
Aside from other considerations given that we have the choice to choose the shot and safely and confidently do so,
there are clear advantages in going for the lungs and heart as they should provide relatively quick kills with proper bleeding. But also these type of shots benefit
from the broader wounding and shock of more powerful rounds even when looking for meat saving shots.
This is an area where frontal section, extra grain and momentum of the larger rounds show a distinctive advantage even in some small-medium
and medium hard to kill like wild boar. To inflict shock we need to keep speeds high enough to induce it even when striking away from the plexus.
The lower limit of some premium bullets as advertised by manufactures is a rather optimistic number and when dealing with light for caliber small caliber can lead
to bad kills. That is why through forensic study we see the best results from small bore higher velocity cartridges. Many professional hunters consider this to be
around 2100fps with many bullets but this is a bit arbitrary IMO as it changes with the animal and shot but one thing is clear the higher you stay from that mark even with meat
saving shots the higher the chances of install kills. I mean, placement still is key obviously.

Today we enjoy amazing bullets and premium hunting ammo but in the end the directives for effective killing have not changed.

These are the dimensions we have to evaluate killing potential:

- Speed
- Weight (grain)
- Sectional Density
- Frontal section
- Terminal design (frontal section x grain x design for the lower speed spectrum)
- Trajectory & Accuracy potential

The entire objective of matching calibers to type of game and body weight is to do well at least in two or three of those dimensions.
If one doesn't do well in at least two or three of those dimensions for the given caliber, then most likely the round is not the ideal round for the job.
The most simplistic version of this exercise is to follow manufactures formula like the new KILLS but to be that can be also a bit arbitrary w/o studying
more other conditions and variables.

Ballistics, like physics, is always a world of trade-offs of some sort.

Regarding a 357 this is a good example of what a +P 357 can do keeping ranges realistic with a popular carbine.
This doesn't mean I suggest this round but also to show how a popular and simple "revolver" round is that and a lot more.
https://www.buffalobore.com/index.php?l=product_detail&p=102


happy new year!

 

[1stmarine]

@Tirod,
Sorry for the confusion. I meant 99% the ranges people hunt in the context of the Gunner in question that was designed for the Northern woods.
Average ranges are between 50 yards from a tree stand to 150yards on a more open area or field with the occasional 200-250 yards but not very frequent.
Lots of shots within the 100 yards. Sorry about the confusion. I should have been more clear I was still talking about the typical hunt in the woods.
For white tail I could probably hunt for the rest of my life with the substantial speed and power of the 6.8SPC either in pistol or carbine but in reality there are clear advantages
about a heavier round, specially one easy to own and shoot. The 6x45 would also offer amazing power in a very simple carbine but ...

In vegetation is thick even for deer there are clear advantages of staying away from 30 caliber and other smaller calibers that might miss the mark.
Specially 30 caliber in the AR15 is not that great in general, compared to other easy to own calibers. See directives posted above.
Deflection is a huge concern and why woods hunters rely on the venerable 35's, 375s and above.
The recoil of the 35 gunner is pretty manageable even with the 10" pistol from a stand. IMO a lot easier to shoot than the 308 w/o the blast and concussion.
If I had to compare the recoil it it would be like an AK pistol with 170gr reloads, but instead AR accuracy.

These 357 bullets are lighter recoil, loose little speed on the AR15 10" pistol and will put a see-through whole in a deers lungs but I think the 180 and 200gr are
hard to beat and one can be very accurate with them.....