What caliber would you like to see become mainstream in the AR-15?

[Z-Michigan]

I picked 6.8 SPC, but really there are plenty of rifle and upper options in 6.8, there just needs to be more ammo options at lower prices. I can't see spending more on 6.8 than I do on .308 Win brand new USA commercial ammo.

Of those not listed, 6x43mm is intriguing. You only need to change the barrel, your bolt and mags still work.

 

[Redneck with a 40]

I'd vote for 6.8 SPC, I'd like to have a Mini 6.8 myself. Its a definite improvement over the 5.56 and it wouldn't be punishing in a 6 lb AR-15. I would not want to shoot 7.62x51 out of a 6 lb AR-15, no thanks.

 

[TonyRumore]

Even though I am not in the big bore AR business anymore, I would still like to see them become more mainstream. I consider myself a pioneer in the big bore AR field, bringing out the 440 Corbon in 1998, quickly followed by the 50AE, 44 Rem Mag, 44 Automag, 357 Automag, and finally the 458 SOCOM and .475 Tremor in 2002. Back then, there was no Alexander Arms Beowulf, no Rock River .458, no Shrubmaster .450, nothing. The only game in town was Tromix. I owned the market....but there was no market. It was just a tiny niche novelty at best.

The big bores never really got any traction until I quit building them.

I wasn't the first to build them though and never claim to, unlike Bill Alexander who wants you to believe he was the first to build a big bore AR in 2002. American Firearms brought out a 50AE in 1994. Many of which did not work and they went out of business shortly therafter.

Tony Rumore
Tromix

Here's a pic of gun #4 built in 44 Rem Mag. There were only six made in that caliber. It was during the ban, hence the solid stock and no threaded barrel.

 

[dougw47]

In my opinion...the momentum behind the 5.56 is so great, the average GI is going to be toting one for the next 25 years or more. To many people in high places think if it ain't broke...and so forth.

There is a good move afoot to re-introduce the 7.62x51 on a limited basis.

The bean-counters see the 6.8 and others as a logistics nightmare...while it sound like a good compromise...how many generals do you know that are good at compromising?

Personally, I don't see it happening. The resistance is too great Old farts like me remember the M14 fondly, new troops LOVE their 16's and M4's for the most part.

I like the AR platform, mine shoots great, it is a hell of a package, has been loved, cussed and discussed for 60 years.

Do you guys really think this administration or the next is going to spring for 500,000 new rifles and ammo? No matter how many of our troops fall?

If a miracle rifle and ammo became available, and I am not saying there is not one already available, our government loves $$$ more than troops. Ain't gonna happen.

I would love to be wrong on this...

 

[highorder]

Can I have one in 9x39mm?

 

[TonyRumore]

In my opinion...the momentum behind the 5.56 is so great, the average GI is going to be toting one for the next 25 years or more. To many people in high places think if it ain't broke...and so forth.

There is a good move afoot to re-introduce the 7.62x51 on a limited basis.

The bean-counters see the 6.8 and others as a logistics nightmare...while it sound like a good compromise...how many generals do you know that are good at compromising?

Personally, I don't see it happening. The resistance is too great Old farts like me remember the M14 fondly, new troops LOVE their 16's and M4's for the most part.

I like the AR platform, mine shoots great, it is a hell of a package, has been loved, cussed and discussed for 60 years.

Do you guys really think this administration or the next is going to spring for 500,000 new rifles and ammo? No matter how many of our troops fall?

If a miracle rifle and ammo became available, and I am not saying there is not one already available, our government loves $$$ more than troops. Ain't gonna happen.

I would love to be wrong on this...

+1

That about sums it up.

Tony

 

[kimberkid]

I'd like to see a 762x45 ...

Similar to the 762x39 but a tad longer a regular 308 diameter projectile and less taper in the case so it can use a regular AR mag

 

[R.W.Dale]

I'd like to see a 762x45 ...

Similar to the 762x39 but a tad longer a regular 308 diameter projectile and less taper in the case so it can use a regular AR mag

sounds like you'd like my 30HRT (.30spc) which does pretty much the same thing but isn't based on a very uncommon and hard to get piece of brass.

 

[Float Pilot]

My Stag has a 1 in 10 twist and a SpecII chamber, Chrome lined.
From the 16 inch barrel my 90 grain hand-loads are going 2,900 fps, the 110s are going 2,550 fps and the 130s are going 2,250 fps. I have even loaded 150 grain round nose bullets to 1,975 fps.

Most loads, including factory ammo, group at 1.0 inches or less at 100 yards. Some hand-loads will group at 0.50 inch.

From zero to 300 yards the 6.8SPC (270 Kurtz) is a darn good cartridge for the small format AR platforms. Particularly when using a barrel length between 14 to 18 inches.

The 6.5 Grendel is also a good cartridge that seems to shine at longer ranges past 300 meters because of the better BC of the 6.5mm bullets.
However all the experiments I tried with it showed that the magic velocities claimed by Alexander Arms usually required a longer barrel than the 6.8 or 5.56mm. Within 300-350 meters it holds no advantage over the 6.8 (assuming same barrel length) and it does not do anything remarkable with shorter barrels.

 

[LS240]

6.5 Grendel. Seems to me the point of "upgrading" calibers in an AR platform is for superior long range power. 6.5 does that better than 6.8, and if I'm not mistaken, actually has more energy than 7.62x51 past 600yds or so. Maybe it was 800, I don't quite remember.

6.5 for sure.

 

[Quiet]

.458Socom

 

[dougw47]

Renington's AR 30 cal...

When Rem. announced its' then new R-15, they showed a new round they had developed for the M4/16 package...the 30 Rem. Used standard-sized AR mags, just held less bullets.

I thought this was promising...but I guess it fizzled. Anybody know what happened?

If this was an ideal world...we might see the 6.5 or 6.8 transition...but the big bosses love that .224 bullet.

Do we really think that just because someone has a better idea, that they are just going to give up the 5.56 that 90% of the troops are carrying?

Get real!

 

[Taurus 617 CCW]

There are always going to be new calibers being developed to attempt to do something that no other caliber can but many of them fall by the wayside when given the test of time. One of my favorites in this category is the .221 fireball. For a varmint round it is pretty good but the .223 outperforms it in ballistics and economics. It does make an impressive pistol round though for those that want to do small critter hunting with a handgun.

I also agree that the 6.5 grendel has a lot of potential for a longer range cartridge in the AR-15 platform. If only ammo manufacturers would start producing it in higher volumes.

 

[W.E.G.]

32-20

 

[45B@cav]

500 S&W Magnum, Yes I know it's a rimmed cartridge but as long as you put the cartridges in the magazine rim in front of rim it would be fine look at .22LR for example.
I think it would be a great rifle for everything, hunting anything on the planet you can get within 200yrds of and maybe further, plinking, home defense, zombies, anti tank (just kidding) and what a conversation piece it would be. Plus you have a rather interesting choice of loads.

 

[kimberkid]

That sounds exactly like what I want!

I wonder if I could get by with reaming of the chamber on a 762x39 AR upper

sounds like you'd like my 30HRT (.30spc) which does pretty much the same thing but isn't based on a very uncommon and hard to get piece of brass.

 

[Hondo 60]

How about something really off the wall like .357 magnum, or .38 spl?

 

[GunsBeerFreedom]

700 NE, just for kicks.

 

[68wj]

I think 6.8 of the options you've listed for deer etc is the best overall for the platform but for those wanting to squeeze out really long range shots (and if you have a long enough barrel) the 6.5 would be ideal.

Great 6.8 FAQ here: http://demigodllc.com/~zak/firearms/6.8SPC/faq.php

Also the .243 / 6mm wildcats would be something to experiment with.

In the end though the military will most likely just return to using 7.62x51mm long before they'll adapt any of the above...IMO.

Another 6.8 vote here. Especially with the trend towards shorter barrels, the 6.8 shines.

BTW: That site hasn't been updated in over a year and there has been some change in the cartridge for the better.

 

[Col. Plink]

7.62x25 actually, or .243

 

[M&PVolk]

6.5 grendel all the way. I don't know why it doesn't have the following of the 6.8? It seems every bit as capable with short range work and its long range is unparalleled by any other AR 15 chambering, even from a 16" barrel.

 

[R.W.Dale]

and its long range is unparalleled by any other AR 15 chambering, even from a 16" barrel.

Any of the WSSM calibers or wildcats will far far outstrip the external ballistic performance of the Grendel by a wide margin from similar bbl lengths

6.5G launches a 120g bullet at 2376fps as per AA
25wssm will launch 120 grain pills out at 2990

 

[metalman8600]

They said after WW2 that most combat takes place within 300yards, but I also read about the long range engagements of Afghanistan. It is best to have both your bases covered, I vote 6.5

 

[R.W.Dale]

That sounds exactly like what I want!

I wonder if I could get by with reaming of the chamber on a 762x39 AR upper

No you would have to start with a fresh bbl as x39 has a larger case head than the 6.8spc case the 30hrt uses

 

[Rokman]

I voted 6.8spc. I like mine, but I handload and have a lot of brass, so what do I care.