What calibers, how many, in the standard AR magazine?

[NiceOldDouble]

What are the calibers that work with the standard .223/5.56 lower, using an unmodified magazine, and how many rounds fit in the standard 30rd mag? I understand you can load 10 .458 SOCOM, single stack, in a standard AR mag, but I am unclear on the rest of the possibilities.

Thanks!

 

[Chdamn]

300 Blackout. You can load all 30 since it's the same cartridge but cut shorter and necked up for a 30 caliber projectile.

 

[NiceOldDouble]

Thanks. I was hearing that 300 Blackout has fallen out of favor: is that the case?
What about 6.5 Grendel, 350 Legend? Is there a comprehensive list somewhere?

 

[Chdamn]

I found this list on another site. Not sure of the accuracy but it looks legit.

Double Stack:

.17 Fireball
.17 Remington
.19 Calhoun
.223 Remington
.20 Tactical
.204 Ruger
.25-223
.300-221 Fireball
.300 AAC Blackout
.375 Reaper
5.56 NATO
7mm Whisper
7.62 X 40mm
6 X 45mm
6.5 X 45mm
.257X45mm

Single Stack:

.440 Corbon (Requires mag spacer)
.458 SOCOM
.458 RMW
.50 AE (Requires mag spacer)
.50 GI (Requires mag spacer)
.50 Beowulf (Requires mag spacer)

 

[Chdamn]

Thanks. I was hearing that 300 Blackout has fallen out of favor: is that the case?
What about 6.5 Grendel, 350 Legend? Is there a comprehensive list somewhere?

I wouldn't say out of favor. But it didn't take off like they originally hoped it would. Factory ammo in super and subsonic is still fairly available, although expensive.

I would say it has become somewhat of a boutique caliber. But that is the case for most of the list I posted above.

 

[Derek8404]

Thanks. I was hearing that 300 Blackout has fallen out of favor: is that the case?
What about 6.5 Grendel, 350 Legend? Is there a comprehensive list somewhere?

6.5 won’t work reliably in standard AR mags.

 

[NiceOldDouble]

6.5 won’t work reliably in standard AR mags.

Thanks. I like 6.5’s. What kind of modifications are needed?

One of the reasons I am think about any of this, is that while I’ve been scouring the neighborhood for 6.5 Grendel, I am seeming plenty of 6.5 Creedmoor in stock, 350 Legend, and .30-06. Seems to me that having guns in calibers that are still on the shelves during times like these would be wise.

I don’t have an -06, but have started to look for one. Curious about Creedmoor and Legend in an AR, and Grendel as well since I have a Howa in that caliber.

 

[Derek8404]

Thanks. I like 6.5’s. What kind of modifications are needed?

One of the reasons I am think about any of this, is that while I’ve been scouring the neighborhood for 6.5 Grendel, I am seeming plenty of 6.5 Creedmoor in stock, 350 Legend, and .30-06. Seems to me that having guns in calibers that are still on the shelves during times like these would be wise.

I don’t have an -06, but have started to look for one. Curious about Creedmoor and Legend in an AR, and Grendel as well since I have a Howa in that caliber.

You will need to by Grendel specific mags

 

[Charlie]

I can use standard GI magazines with 450 Bushmaster but not the plastic ones with the ridge down the middle unless I use very short bullets.

 

[Jerzsubbie]

I wouldn't say out of favor. But it didn't take off like they originally hoped it would. Factory ammo in super and subsonic is still fairly available, although expensive.

I would say it has become somewhat of a boutique caliber. But that is the case for most of the list I posted above.

I’m optimistic that the Wolf/Barnaul offerings may change that. The current market shortage isn’t helping though.

 

[Flashpoint]

I wouldn't say out of favor. But it didn't take off like they originally hoped it would. Factory ammo in super and subsonic is still fairly available, although expensive.

I would say it has become somewhat of a boutique caliber. But that is the case for most of the list I posted above.

And that is really surprising considering the popularity of suppressors. Ever since I got one now I want all my ammo heavy and slow.

 

[Chdamn]

And that is really surprising considering the popularity of suppressors. Ever since I got one now I want all my ammo heavy and slow.

I really think they expected the military to pick up the caliber. And they didn’t.

They ran all kinds of tests and dog an pony shows with the M249’s suppressed.

 

[Desolo]

Ive never needed a "spacer" for .50 Beowulf, for what its worth.

 

[Combat Diver]

Thanks. I like 6.5’s. What kind of modifications are needed?

One of the reasons I am think about any of this, is that while I’ve been scouring the neighborhood for 6.5 Grendel, I am seeming plenty of 6.5 Creedmoor in stock, 350 Legend, and .30-06. Seems to me that having guns in calibers that are still on the shelves during times like these would be wise.

I don’t have an -06, but have started to look for one. Curious about Creedmoor and Legend in an AR, and Grendel as well since I have a Howa in that caliber.

The Grendel and Legend will work in a AR15, the Creedmore will need the larger AR10 platform. I do know that the 6.8mm SPC which has a larger case will need specific mags to load to full cap. However, IIRC both the Grendel and SPC can use a standard AR mag without modification if you only load a few rounds. This is due to the rib in the mag body that supports the case neck interfering with the larger diameter cases.

CD

 

[MDof2]

Add 450 Bushmaster to the single stack list.

 

[Tug McClutchin]

Thanks. I was hearing that 300 Blackout has fallen out of favor: is that the case?
What about 6.5 Grendel, 350 Legend? Is there a comprehensive list somewhere?

What makes you think 300bo has fallen out of favor? Seems to be incredibly popular as far as variants for the ar-15. I would go so far as to say it is HANDSDOWN the most popular. Ammo has gotten harder to get and more expensive but what ammo has not in recent months.