What's with all the new calibers for the AR?

[Mags]

6.8 SPC II, 6.5 Grendel, 300 Whisper, 300 Blackout......

Just stumbled upon a 1924 Remington Model 8 in 30 Remington. Which was Remington's way of getting 30-30 performance from a semi-auto rifle back in 1906. After some research I found out all the 30 Rem factory ammo dried up in the 80s and it can only be obtained through handloaders and remanufacturers. So why did they not use this round when they were coming up with "more powerful rounds" for the AR?

Here are some specs:

30 Remington
Bullet Diameter: 308
150 grain Velocity: 2364 ft/s Energy: 1859 ft lb
170 grain Velocity: 2114 ft/s Energy: 1682 ft lb

6.8 Remington SPC II (parent case is the 30 Remington)
Bullet Diameter: 277
120 grain Velocity: 2460 ft/s Energy: 1612 ft lb

6.5 Grendel
Bullet Diameter: 264
130 Grain Velocity: 2510 ft/s Energy: 1818 ft lb

300 Whisper
Bullet Diameter: 308
125 grain Velocity: 2100 ft/s Energy: 1224 ft lb

300 AAC Blackout (the newest on the block)
Bullet Diameter: 308
123 grain Velocity: 2280 ft/s Energy: 1420 ft lb

So my point is, why was the 30 Remington not chosen for an AR15 conversion? Why was the wheel reinvented with each caliber instead of trying an existing caliber? I bet all the 30 Remington would need to work in an AR15 would be a barrel, 6.8 bolt, and 6.8 mags. If I had the money I would love to try it!

 

[R.W.Dale]

because both 30remington and it's parent 30-30 win are far far too long to fit into an AR15 magwell.

The reason for all the new caliber is that in the past decade or so the AR pattern has become by far the most standard and widely found action by the us gun owner EVER. So just like with the levergun 130 years ago the cartridges are changing to match the platform.

Americas deer rifle is no longer a 20" winchester 94, today it's a 16" M4gery. Think of the AR platform as the iphone-ipod of the gun world and all these new calibers are the apps that make owning one worthwhile

 

[Mags]

I don't know, about that...
The 30 Rem's OAL is only 2.52, the 6.8's OAL is 2.31. I'm sure with lighter bullets it would work well.

 

[suzukisam]

because there are far better cartridges available, like the blackout.. when you use an old cartridge for a new platform than you have to bring it's "emotional baggage along for the ride. what I mean by that is sort of like the 45-70, 38 spl, and 45lc.. all these cartridges are far more capable than the weapons they were originally designed for, so if you make a "new" version of the same cartiridge you have all the liability of it being used in an old rifle. so such as the 357 mag, 450 marlin, they make a whole new cartridge.. not to mention mall ninjas and tacticool people don't want an old lever cartridge in their EBR..

 

[R.W.Dale]

I don't know, about that...
The 30 Rem's OAL is only 2.52, the 6.8's OAL is 2.31. I'm sure with lighter bullets it would work well.

the 6.8 takes up every bit of the ar's magwell so with an additional .2" the 30rem might as well be 2" too long.

Shooting lighter bullets to shorten COL in a cartridge already shooting very short stumpy poor BC projectiles is a surefire recipe for boor ballistics and performance. Just like with 30-30 bolt actions the limited mag length prevents you from using all but the shortest varmint weight spitzers. I've been there and done that a 110g varmint HP loaded in 30-30 (same as 30 rem) makes for a longer COL than 150-170g RN bullets

 

[Mags]

Well alright, I guess it just won't work.

But if I had the dough I sure would try it!

 

[suzukisam]

you could put it in a .308 platform, but there are other calibers that would utilize the size with better performance

 

[ILikeLead]

Mags said "After some research I found out all the 30 Rem factory ammo dried up in the 80s and it can only be obtained through handloaders and remanufacturers"

I think this would be a major reason too as most gun owners are not reloaders!

 

[R.W.Dale]

you could put it in a .308 platform, but there are other calibers that would utilize the size with better performance

Remember the ar10 platform is NOT standardized across manufacturers like the 15 is, so parts availability, cost and customizability are going to correspondingly suffer

 

[suzukisam]

whats that have to do with the fact that they are larger, and what isn't standardized is very minimal, they are pretty standard for the most part

 

[chris in va]

So why did they not use this round when they were coming up with "more powerful rounds" for the AR?

They are...it's called the 'Remington 30 AR' round now.

http://www.remington.com/product-families/ammunition/centerfire-families/30-remington-ar.aspx

Approaches 308 ballistics.

 

[Mags]

I think this would be a major reason too as most gun owners are not reloaders!

Well most of the new calibers for the AR such as the 300 blackout & whisper,6.5, and 6.8 are mostly handloader calibers as ammo isn't widely available.

Plus maybe if the 30 rem went into the AR they could turn the factory back on.

 

[R.W.Dale]

They are...it's called the 'Remington 30 AR' round now.

http://www.remington.com/product-families/ammunition/centerfire-families/30-remington-ar.aspx

Approaches 308 ballistics.

and aside from part of the name and bullet diameter shares NOTHING with the 30rem being discussed here.

Beside the fact that the 30RAR is pure vaporware and has been goin on 4 years now.


I like the new trend of going back to and necking up the .223 case as with the 300blk, 25-45sharps and 6x45. This is the case head the ar15 was designed around and works best with and lets you retain ALL standard parts except the bbl

 

[chris in va]

and aside from part of the name and bullet diameter shares NOTHING with the 30rem being discussed here.

I fully understand that. But it's the 30 caliber that *should* be in the normal AR15 platform, not some stretched out cartridge from yesteryear.

 

[R.W.Dale]

I fully understand that. But it's the 30 caliber that *should* be in the normal AR15 platform, not some stretched out cartridge from yesteryear.

agreed! But sadly it's ship has came and went, with an opportunity squandered by the rife ineptitude of the folks running remington today.

But that's fodder for a completely new thread

 

[SentinelStrategic]

FWIW, the .30-Rem is probably on its way out. It's a hunting cartridge, but I don't see the market getting any stronger than it is right now. The .30 Remington was just too big of a cartridge for tactical use, and magazine capacity took a hit. I am under the assertion that the tactical community drives the AR market, and the best tactical cartridge will be the winner. The .30AR is apparently not that cartridge.
The .300 Whisper is still around, being eclipsed by the .300 AAC Blackout. In fact, companies like Noveske have discontinued their production of .300 Whisper components to concentrate on the .300AAC.
Both the .30Rem and .300Whisper are basically being replaced by the .300AAC, in my opinion. I've seen pictures of guys with hogs they shot, tactical related shooting media, and reports of near-silent operation with sub-sonic 220gr OTM loads. They probably all have their place, but it seems like the .300AAC does it all and has the best logistical support throughout the shooting industry. I think they all are trying to fill one niche, and there's only room for one cartridge to do it best. Just my observation of it, though.
Everybody is trying to carve a new niche into the genre. I think AAC has succeeded pretty well.
The 6.8SPC was a SOCOM-designed cartridge for Afghan cave hunting. Significantly better close range terminal performance than 5.56mm.
The 6.5Grendel is a long range match cartridge adapted to the AR platform to compete in the 6.5 category.

 

[IMARMED45ACP]

The AR platform is a phenomenal base for modulation. I am looking to get in latest AR craze. With the specs you've provided, I find the 6.5 Grendel, and 6.8 Remington SPC; to be great North American game rounds.
As an entry level AR enthusiast; which would be best for me?5.56 NATO, .223 Remington?

 

[Mags]

Welcome to THR!

Well since it's your first AR I reccomend a 5.56 but if hunting will be it's primary purpose maybe one of the 6. whatevers will better suit your purpose.

 

[SentinelStrategic]

As an entry level AR enthusiast; which would be best for me?5.56 NATO, .223 Remington?

You can shoot .223 out of a 5.56. You can't shoot 5.56 out of a .223. Get a rifle that is barreled for "5.56mm"(5.56x45, 5.56mm NATO, etc).

 

[68wj]

When developing the 6.8 SPC, they did start with the .30 Rem. They cut it back and tested various diameter bullets. The .277 was the best compromise of terminal ballistics from gel testing and exterior ballistics on the range.

Interesting that you listed the 120 grain load as it has only been on the market for about a month (Hornady 120 SST). Weights around 110 seem to be the standard. Wilson Combat is now loading ammo and lists 2700fps, 1780ft/lbs for their 110 Hornady OTM out of a 16" AR barrel. The 95gr TTSX is 2850, 1715ft/lbs.

Now, what's with all these different cars on the road?

 

[Mags]

68WJ, I have no problem with having an abundant choice of calibers. I just don't see the numbers being all that different on paper regarding performance among all these new upstarts.

I would take the plunge with one of these calibers but just like with the 30 Rem you can't go to Wal-Mart and pick up a box of any of the AR specific cartridges other than 5.56.

 

[SentinelStrategic]

The cartridges that are out for ARs fit into one of three categories: intermediate, heavy intermediate, and full power/long range.
The standard/intermediate cartridges are the 5.56 and the 5.45x39 loads, etc.
The heavy intermediate loads are those designed to basically compete with the power of the AK/AKM's 7.62x39 for more close-range energy. These are your 6.8SPC, .300 Whisper, .300AAC, .30AR, .450 Bushmaster, .50 Beowulf, etc. Basically short to mid-range high-energy rounds.
The full power/long range loads are you .308s, .338Federal, and 6.5Grendel, etc.

Ultimately, it comes down to your choice. It's Baskin Robbins 31 Flavors.
Aside from .223/5.56 and .308, you pretty much have to expect to do most of your ammo shopping online if you don't reload.

 

[Cop Bob]

Three Reasons...

#1, The AR, while off to a rocky start has proven itself to be a rock solid winner.

#1. Because we as Americans are competitive has Hell. We will try to to out do, out run, out drive, out shoot, out perform anyone, in any arena, .. who else would be racing lawnmowers? Yeah I know it caught on in other places, but it started here..

#3, Because somebody with a vivid imagination, a mechanical mind, and access to a mill and a lathe said, "WADDYA MEAN IT WON'T FIT" "

Which is the back yard engineers equivalent to "HEY, HOLD MY BEER AND WATCH THIS!!!!

 

[suzukisam]

Bob you forgot one...

#4 marketing departments have to get paid to do something and whether you talking about guns, camo, bullets, tree stands, lead sleds or underwear, "the next big thing" is the only words some shoppers need to hear..

Another thing to note is some companies will not allow their product rights to be bought, for example 6.5 grendel is a great little cartridge, but is lacking in availability because the owner is a dufus.. so you have the same cartridge called .264 lbc. and I believe the 300 AAC is the same as a 300 whisper if you look at the specs it's darn close...

 

[rogertc1]

Mags, You forgot 50 Beowulf, 7.63X39, 7.62X25, .22LR and 50 BMG