Ar10 or 300 blackout build

BenL · Nov 16, 2012

I have both and would recommend the 300BLK.

The Blackout is more standardized (as an AR platform), lighter, and more versatile. The brass will always be plentiful (cut down from 5.56) and can shoot 220gr subsonic (with a suppressor, very quiet) or 125gr supersonic. Even if you reload, the .308 will be more expensive. I use 42gr of powder per charge (versus 11gr for the Blackout) and once-fired brass is ~3X the price. Even the dedicated parts for a .308 AR (lower, BCG, etc...) are ~2X the price of a Blackout.

Indiana Jones · Nov 16, 2012

BenL said:
I have both and would recommend the 300BLK.

The Blackout is more standardized, lighter, and more versatile. The brass will always be plentiful (cut down from 5.56) and can shoot 220gr subsonic (with a suppressor, very quiet) or 125gr supersonic. Even if you reload, the .308 will be more expensive. I use 42gr of powder per charge (versus 11gr for the Blackout) and once-fired brass is ~3X the price. Even the dedicated parts for a .308 AR (lower, BCG, etc...) are ~2X the price of a Blackout.

the round (.308) is also 2x more effective, and can lethally reach out what like 5x farther?

BenL · Nov 16, 2012

Indiana Jones said:
the round (.308) is also 2x more effective, and can lethally reach out what like 5x farther?

Both are just as lethal to the paper, which inevitably is what everyone is shooting with these.

The upside to a 308AR is if you want to shoot milsurp ammo; M80 .308/7.62x51 can be had in large quantities for ~$0.70 a round.

rsilvers · Nov 19, 2012

Indiana Jones said:
the round (.308) is also 2x more effective, and can lethally reach out what like 5x farther?

308 is much more effective, but it is a lot more recoil and the guns are much heavier. I have struggled with the 308 vs 5.56mm debate in the past for my own home defense, and I really wanted to make 308 work. I bought SR25s, FALs, and M1As. In the end, they are just too big and heavy for me. 5.56mm won most of the time, and 308 for longer range hunting.

Now that 300 BLK is out, I would say pick that for most use, and 308 for when you know you will shoot farther. So my vote is - get both and use 308 when you need it, and 300 BLK the rest of the time.

rsilvers · Nov 19, 2012

BenL said:
The upside to a 308AR is if you want to shoot milsurp ammo; M80 .308/7.62x51 can be had in large quantities for ~$0.70 a round.

51.8 cents a round for 300 BLK - a bunch cheaper than 30-30.

374750_262316480481481_203519439694519_767459_1415306112_n.jpg

rsilvers · Nov 19, 2012

Indiana Jones said:
...and can lethally reach out what like 5x farther?

No - 300 BLK is much closer to 308 than you think. Let me give you three examples:

110 grain TAP 308 is 2800 fps from a 16 inch barrel. It drops to the muzzle velocity of 300 BLK at 130 yards. So 308 only has a 130 yard advantage for this bullet. If we consider 400 fpe to be the max range, then that is 610 yards for 308. 300 BLK drops to that energy at 475 yards.

610 / 475 is 1.28, so 308 has 1.28 times the range of 300 BLK.

To help prove your point though, I will pick the other end of the extreme - a heavy high-BC bullet and go by a velocity limit.

175 grain from 308 is 2603 fps. 300 BLK 175 grain is 1900 fps. It drops to a 300 BLK muzzle velocity at 420 yards.

(reference: http://digital.turn-page.com/issue/16258/19)

Now if we consider the 175 grain 308 range from a 16 inch barrel to be 1000 yards (the bullet is at 1180 fps then), 300 BLK will reach that velocity at 580 yards.

1000 / 580 is 1.7, so 308 has 1.7 times the reach of 300 BLK in this example that favors 308 more.

And a third way to look at it as by max point blank range (+- 3 inches). This time, I will pick the best practical bullet for each caliber.

16 inch 308 with Mk188 LR ammunition - 246 yards.
16 inch 300 BLK with Barnes VorTex - 220 yards.

So 308 has 1.1 times the range for which you can shoot without adjustment of sights or compensation.

In summary, 308 has between 1.1 and 1.7 times the range of 300 BLK, depending on the bullet and metrics.

It is fair to call it 1.5 times more reach, but not 5 times.

So the question is - is the larger, heavier, and more expensive rifle - with much more recoil and vastly more noise and blast, worth it for 1.5 times the reach? Yes if you want it. No if you want to save weight. I would always want to own both.

Shot with 300 BLK Barnes:

sdOne · Nov 21, 2012

rsilvers said:
No - 300 BLK is much closer to 308 than you think.

I was back and forth regarding this, so thank you very much for the post.

Sent from my Little Robotic Tether.

drking2 · Nov 21, 2012

Thanks everyone for the info, I think I am going to 300 Blackout this build. Just hold out for my left hand ruger gunsite in 308.

wasntme · Feb 23, 2013

.300 AAC BLK Barnes 125 gr TTSX Ferral Pig Head Shot right behind the eye golfball size exit:

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Russ D · Feb 23, 2013

Don't hunt with FMJ's. Not saying anyone did but it's illegal.

BradMacc82 · Feb 23, 2013

Hmm, wonder if an OTM round is considered "Expanding" then.

Russ D · Feb 23, 2013

BradMacc82 said:
Hmm, wonder if an OTM round is considered "Expanding" then.

I thought all the UMC was FMJ.

BradMacc82 · Feb 24, 2013

Russ D said:
I thought all the UMC was FMJ.

IDK, that's why I'm asking now.

Don't need to go getting anyone in between a rock and a hard-place if it can be avoided.

Looking at some info from other sources, it appears OTM rounds (like the 220gr Rem's) are really referred to as OTM to keep them kosher for use in battle, since typical hollow-point's/expanding rounds are a no-no.

I don't know how a closed-tip round would be classified, such as the 115gr Rem - looks like it may be time to make some calls and get some answers.

hishaun84 · Feb 24, 2013

I finished my 300BLK build in late November of last year. Only bought a few hundred rounds of ammo for about .70/round. Now I can't find ammo anywhere. There have been a few cases here and there but mostly at $2-$3/ round.

I'd say if you go 300BLK you need to reload if you don't already. If not, go .308. I have an awesome gun now that I can't shoot. F.

wasntme · Feb 24, 2013

hishaun84 said:
I finished my 300BLK build in late November of last year. Only bought a few hundred rounds of ammo for about .70/round. Now I can't find ammo anywhere. There have been a few cases here and there but mostly at $2-$3/ round.

I'd say if you go 300BLK you need to reload if you don't already. If not, go .308. I have an awesome gun now that I can't shoot. F.

save all your 5.56 and .223 brass and become friends with someone who does reload. Im in belcamp, md. if someone near me wanted to come up and load some rounds with my equiptment I would have no problem with that as long as they brought their own components.

wasntme · Feb 24, 2013

Russ D said:
Don't hunt with FMJ's. Not saying anyone did but it's illegal.

Who's hunting with FMJ's I know im not. I built all of mine for hunting and I only use expanding bullets, Out of all of my lighter hunting calibers the .300 BLK is my favorite! It's just so devistating!!

BradMacc82 · Feb 24, 2013

wasntme said:
Who's hunting with FMJ's I know im not. I built all of mine for hunting and I only use expanding bullets, Out of all of my lighter hunting calibers the .300 BLK is my favorite! It's just so devistating!!

He wasn't referring to you.

Russ D · Feb 24, 2013

wasntme said:
Who's hunting with FMJ's I know im not. I built all of mine for hunting and I only use expanding bullets, Out of all of my lighter hunting calibers the .300 BLK is my favorite! It's just so devistating!!

Nope just throwing it out there sin almost all of the 300BLK out there now is FMJ.

StickerLT · Feb 24, 2013

I have an AR10, and love it. No experience w/ the 300 BLK, but after reading through this thread I want one.

Russ D · Feb 24, 2013

StickerLT said:
I have an AR10, and love it. No experience w/ the 300 BLK, but after reading through this thread I want one.

You don't even know how much you should want one.

Ar10 or 300 blackout build

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