So thinking about building an AR in some caliber other than 5.56. I've been considering the following and wanted to hear other people's experiences.


300blk
I really like the idea of this caliber since there's no need to buy new mags and bcg. However, I'm wonder if there's any benefit to the 300blk if I dont have any plans to run a suppressor.

6.8spc
I hear alot about the 6.8 but not sure I'm sold on it yet. I like the idea of a caliber that is in between 5.56 an 7.62x51, but dont like the idea of having to buy new mags and bcg

5.45x39
Basically I guess this is just to take advantage of cheaper ammo. If I go 5.45 route I'll probably get an 20" A2 upper and just use iron sights

7.62x39
This is my least likely choice. I've heard of alot of issues with this caliber in an AR platform, plus I already have an AK.

With the 6.8 you need new magazines and a new bolt, not bcg. Of of what you listed because of accuracy and drop its the only one I would probably choose.

I would go 6.5 grendel or just get a 308 AR.

what use?

Didn't think about a 6.5

Just for fun really. I dont use tactical guns for hunting so not worried about making a kill. At this point I'm leaning pretty heavily toward the 5.45x39, but intrigued by other trendy calibers. But then I figure I can get an AK74 for way cheaper than a 5.45 AR.

My current project is a 6.8. Sure I would like to have a 308 but I like the fact that the 6.8 is 95% compatible with my 5.56 stuff. My primary use will be hunting with it though. If I was just looking for a fun gun I dont see how you can beat the 5.56.

LOL, already have 2 ARs in 5.56. So a third wouldn't be any fun

Well in that case you should go to the completly opposite end of the spectrum and get a 450Bushmaster or 50Beowolf. I cant imagine anything more fun than that.

Do you have a varmint style and m4 style 5.56?

Yes the ammo is cheap, but depending on where you go to shoot much of that cheap ammo won't be allowed. Call me special and you can never have too many guns whatever but spending $700-$2000 to save a few hundred on ammo doesn't seem like it makes the most sense...

If you aren't hunting at all with it, not seeing any advantage to going 5.45 or 6.8.

So I'd go JCBs route and get something special... or possible a 5.56 pistol? They can really piss folks off at shooting ranges.

The 450 Bushmaster or 50 Beowolf if want to go BIG. Those would be a lot of fun and if you ever wanted to hunt with it in Texas you would not be under gunned.

A different route would be an upper in 5.7X28. 50 round mags and they fit on top not haging down. Fun little round about like a modern 22 Hornet

Take a look at the 6mm AR. It is the 6.5 Grendel necked down to 6mm. Uses necked down Grendel brass and a 7.62x39 bolt.

http://www.6mmar.com/

Don't have a varmint style, but do have m4 and soon to be SBR. Both of those are pretty tacticooled out.

Honestly I was thinking of going KISS and doing a basic 20" A2 upper with standard handguards, A2 stock. Dont know why but the standard AR15 look is calling to me. Maybe even run some triangular handguards

6.8 SPC if you want a 12" SBR for hunting
6.5 Grendel if you want a mid-range rifle
.300 Blackout if you want a subsonic suppressed carbine

LOL, never considered those. Dont see those everyday

300 BLK suppresses well. This has been interpreted as "You want 300 BLK if you plan to use a suppressor." With the Telephone Game, this has been translated to "The 300 BLK is just if you have a suppressor." That is not the case. It needs a suppressor no more than 7.62x39mm or 30-30.

The 300 BLK has as much energy from a 16 inch barrel as 5.56mm has from a 24 inch. You get 8 inches of barrel for free.

It is a great "normal" round - so don't believe it is mostly for subsonic. I am the project lead at AAC. I know why I got the cartridge made. It is for people who want to shoot 30 caliber bullets from an AR-15 using normal magazines without giving up the 30 round capacity.

See this photo? That is at 300 yards. And even if the barrel were just *6 inches*, it would still do that at 200 yards!

Those 0.60 caliber holes are 20-24 inches deep at that range.



I put all the updates here: https://www.facebook.com/300aacblackout

There are 90 companies making products for it. The best part about it is that the ammo is much less expensive than other alternative cartridges.

The most info is here: http://www.300blktalk.com/forum/