AR-15 magazines/different calibers?

[Blacktail Sniper]

What are you folks using in your AR platforms that are in calibers other than .223/5.56?

Are there caliber specific magazines for rounds like .300 Blackout, 7.62x39, etc.?

Or do they function as is in a standard AR mag or are there modifications needed?

Ae there some brands that function better than others?

[lamrith]

300blk is a 223 case sized to 30cal, it is designed to use std mags so any and all std mags should work without any changes (aside from clearly marking it is 300blk ammo in it..)

*39 I believe the use more "banana" shaped mags.

6.5 grendel CAN use a std mag, they fit, but the follower is not optimal and it could lead to feeding issues.  I tested a few times with mine and it worked ok, but since I have dedicated grendel mags I just use those and do not bother using std mags.

[theleo]

300blk is a 223 case sized to 30cal,

It's off the old 221 fireball, much different case than the 223. If it was off the 223 it wouldn't fit the AR15 platform.

[Biggerhammer]

You can run most .223/5.56 case based cartridges from Magpul magazine. As in .300BLK, .223, 5.56, 6x45 etc.

I use ASC magazines for the American 30, 6.5 Grendel, 6x6.8 SPC, .243 LBC & .264 LBC. The ASC mags I use are marked either 6.8 SPC OR 6.5 Grendel on the follower. Both mags work without issue on all the 6.5 Grendel or 6.8 SPC based cartridges. Most ASC mags run about $15.00

Never dealt with a AR in 7.62x39.

[Blacktail Sniper]

Thanks everyone!!

[lamrith]

300blk is a 223 case sized to 30cal,

It's off the old 221 fireball, much different case than the 223. If it was off the 223 it wouldn't fit the AR15 platform.

Fact is 300blk uses cut 223 brass so case diameter base shape is the same.  It was designed that way to allow usage of all current ar15 items other than barrel.

Sent from my SAMSUNG-SM-G870A using Tapatalk

[dontgetcrabs]

I have a couple 6.5 Grendels, a 6x45 which is simply a necked up 223, and a 260 Rem, but that is an AR-10. The Grendel uses a different bolt and ideally Grendel specific mags. The 6x45 uses standard 223 bolt and mags.


The 300BLK uses a standard bolt, not sure about mags for it though? It is simply a shortened 223 case necked to accept 30 caliber bullets.

There are many 223 wildcat combos that just need a barrel swap with regular bolt and mags.

[theleo]

300blk is a 223 case sized to 30cal,

It's off the old 221 fireball, much different case than the 223. If it was off the 223 it wouldn't fit the AR15 platform.

Fact is 300blk uses cut 223 brass so case diameter base shape is the same.  It was designed that way to allow usage of all current ar15 items other than barrel.

Sent from my SAMSUNG-SM-G870A using Tapatalk

Fact, the 300 blackout is a SAAMI standardized 300 whisper. The entire whisper line is based on the 221 Fireball. There's no cutting down of a 223 case required to form Whisper or Blackout case. Just necking up the fireball.

[Yondering]

300blk is a 223 case sized to 30cal,

It's off the old 221 fireball, much different case than the 223. If it was off the 223 it wouldn't fit the AR15 platform.

Fact is 300blk uses cut 223 brass so case diameter base shape is the same.  It was designed that way to allow usage of all current ar15 items other than barrel.

Sent from my SAMSUNG-SM-G870A using Tapatalk

Fact, the 300 blackout is a SAAMI standardized 300 whisper. The entire whisper line is based on the 221 Fireball. There's no cutting down of a 223 case required to form Whisper or Blackout case. Just necking up the fireball.

You're being obtuse, without really knowing what you're talking about. 300 Blk brass is almost always formed from shortened 223 cases. Yes, you can form it from 221 brass, but it's much less common, and not usually done any more. It doesn't matter for this discussion anyway, either way normal 5.56 mags are used.

One modification to 5.56 mags for 300 Blk is for use with heavy cast bullets; the side ribs are removed from the mag to keep the rounds from going pigeon toed. Pretty easy to do on a Pmag with a file.

I use ASC mags for 6.8 based wildcats; I wouldn't call them "tier 1" but they are OK.

[lamrith]

300blk is a 223 case sized to 30cal,

It's off the old 221 fireball, much different case than the 223. If it was off the 223 it wouldn't fit the AR15 platform.

Fact is 300blk uses cut 223 brass so case diameter base shape is the same.  It was designed that way to allow usage of all current ar15 items other than barrel.

Sent from my SAMSUNG-SM-G870A using Tapatalk

Fact, the 300 blackout is a SAAMI standardized 300 whisper. The entire whisper line is based on the 221 Fireball. There's no cutting down of a 223 case required to form Whisper or Blackout case. Just necking up the fireball.

The current common practice to get 300blk brass if not purchased as 300blk is to cut and resize 223/556 brass, because it is so readily available.  I was trying to keep it clean and simple without adding another caliber to the discussion.

[theleo]

300blk is a 223 case sized to 30cal,

It's off the old 221 fireball, much different case than the 223. If it was off the 223 it wouldn't fit the AR15 platform.

Fact is 300blk uses cut 223 brass so case diameter base shape is the same.  It was designed that way to allow usage of all current ar15 items other than barrel.

Sent from my SAMSUNG-SM-G870A using Tapatalk

Fact, the 300 blackout is a SAAMI standardized 300 whisper. The entire whisper line is based on the 221 Fireball. There's no cutting down of a 223 case required to form Whisper or Blackout case. Just necking up the fireball.

Which has nothing to do with the question at hand, being if it will work with factory ar15mags.  For simplicity I was stating it so that everyone would understand without getting to the historical Saami spec details of the round which would add confusion. 

The current common practice to get 300blk brass if not purchased as 300blk is to cut and resize 223/556 brass, because it is so readily available.  Using that current common practice was an easy way to help the OP and other understand that it will work in the same mags as 223/556.  I was trying to keep it clean and simple without adding another caliber to the discussion.

You guys are correct, for the sake of mags it doesn't matter. I was just pointing out the parent case was not a 223 but the 221 Fireball. Parent case does not mean what you choose to alter to make the brass but the original cartridge design the creators choose to alter to make their new round. You could make a 338 federal brass out of 243 brass or by cutting down and reforming 30-06 brass as well.

I was just pointing out incorrect information gents.

[pianoman9701]

I just got some 6.5 Grendel from these guys. They have a sliding pricing scale for increasingly larger numbers of mags (1-4, 5-9, 10-14, etc.), and offer free shipping for orders $100 and more. http://www.jgsales.com/index.php. I looked on www.loyalsguns.com to see if you had any listed, Hammer, and you didn't.

[Yondering]

I was just pointing out incorrect information gents.

It wasn't incorrect though. The 300/221 was based on the 221 Fireball case; the 300 Blk was based on a cut down 5.56 case. They are very similar, the difference is in the neck thickness. The original statement you responded to was correct.

[theleo]

I was just pointing out incorrect information gents.

It wasn't incorrect though. The 300/221 was based on the 221 Fireball case; the 300 Blk was based on a cut down 5.56 case. They are very similar, the difference is in the neck thickness. The original statement you responded to was correct.

I'm just trying to get this rite so I understand and don't get screwed up in the future.

The Blackout case is not based off of the Fireball case even though their case lengths are with in .032 of each other (the Fireball being longer), shoulder at the same location, shoulder at the same angle, and they call for the neck thickness to be within .0025" of each other (with the Fireball calling for thicker)? Instead it's the 223 that is cut back with shoulder and neck reformed?

I'm confused.

[dontgetcrabs]

I thought the fireball neck was thinner?