Considering A Featherweight 300 Blackout Build

[okie john]

I’m considering a new upper for hunting deer and hogs with my DD M-4. I’m thinking 300 Blackout. I consider the 5.56 adequate with modern ammo but minimum bore diameter for big-game hunting in Washington is .224”, so it’s a NO GO at this point.
• I’m on my feet all day when I hunt, so I want to go super lightweight. I’m thinking smooth handguards, no BUIS, ultralight 18-20” barrel.
• Sights will be RDS for brushy country, and an ACOG for more open country.
• I’ll probably never use a can on it.

What am I overlooking? Twist rate? Gas system length?

Thanks,


Okie John

[QuietShootr]

I’m considering a new upper for hunting deer and hogs with my DD M-4. I’m thinking 300 Blackout. I consider the 5.56 adequate with modern ammo but minimum bore diameter for big-game hunting in Washington is .224”, so it’s a NO GO at this point.
• I’m on my feet all day when I hunt, so I want to go super lightweight. I’m thinking smooth handguards, no BUIS, ultralight 18-20” barrel.
• Sights will be RDS for brushy country, and an ACOG for more open country.
• I’ll probably never use a can on it.

What am I overlooking? Twist rate? Gas system length?

Thanks,


Okie John


errr.... 5.56 is .224. Ask anyone who reloads.

[okie john]

I stand corrected. Per the Washington WDFW game regs, "Big game, except cougar, must be hunted with a minimum of 24 caliber (6mm) centerfire rifle."

My mistake.


Okie John

[rob_s]

I'm also not sure you gain much going over 16" on the 300.

Bear in mind that it recoils more, but for a hunting, one shot, kind of thing that might not matter.

[wahoo95]

Carbine gas and 1/8 should be fine for 16" barrel.

[okie john]

I'm also not sure you gain much going over 16" on the 300.

Bear in mind that it recoils more, but for a hunting, one shot, kind of thing that might not matter.

This is the kind of answer I'm looking for. Recoil isn't much of an issue--right now I use a light 308 bolt gun, so the 300 in a gas gun shouldn't kick as hard.


Okie John

[mark5pt56]

Don't be fooled by the "smooth" handguards and weight, some are more or just as much as railed. Also, consider future applications to where you may want them.

I built a lw 5.56 upper last year for my daughter and decided I had to have one for myself. Anyhow, I used the Centurion rail on mine for a few reasons. It's light, high quality, uses standard barrel nut, has QD points-where I actually want them, not requiring me to buy someones QD attachments because of shit ass excuse about not being able to machine them into the lightweight rail. I've used and broken the Troy rails, and I won't try them again. Don't see any others that offer what I want.
Instead of two optics, you may want to look at a low power variable.

So, I decided to mimic the 5.56 build with the exception of a 9" rail instead of the 10"
I will use the existing lower and just switch uppers.

The 5.56 builds with T1's, whole rifle is 7 pounds, Troy sights, no sights on the 300 BLK

AAC 16" BLK barrel
Rainer A4 w/o FA and with M4 ramps
Centurion 9" rail
BCM FA BCG
BCM mod 5 Gunfighter CH
Leupold VX-R 1.25-4 with Leupold IMS mount.
Rather certain I will use the MCD comp, just want something small and effective. http://www.ar15performance.com/inc/sdetail/2121/2206

[Nightvisionary]

I’m considering a new upper for hunting deer and hogs with my DD M-4. I’m thinking 300 Blackout. I consider the 5.56 adequate with modern ammo but minimum bore diameter for big-game hunting in Washington is .224”, so it’s a NO GO at this point.
• I’m on my feet all day when I hunt, so I want to go super lightweight. I’m thinking smooth handguards, no BUIS, ultralight 18-20” barrel.
• Sights will be RDS for brushy country, and an ACOG for more open country.
• I’ll probably never use a can on it.

What am I overlooking? Twist rate? Gas system length?

Thanks,


Okie John


I think you are overlooking the 6x45. The 6x45 meets your minumum caliber restriction and it will out perform the 300 blackout in regards to velocity, bullet drop, wind drift, and energy.

The 6x45 loaded with a Barnes 85 grain TSX at 2750 FPS is my hunting load for the 6x45. I could push it a little faster but I get good accuracy at that velocity.

[mark5pt56]

Oh--and something I can buy off the shelf and then reload if I want---

[AKDoug]

Okie- I have been considering the same thing. One upper builder I am looking at is Mike Milli at DTech www.dtechsuperstore.com He'll build just about anything you want. I'm looking at having him do a 16" 300 Blackout with a fluted heavy barrel and using his float tube. I need to ask him how much it weighs. High quality, super accurate, hunting upper for much less money than many 300 Blackouts on the market.

I am strangley attracted to his WSSM uppers also, but I'm not sure I want to head off that deep into the wildcat land.

[rob_s]

Okie- I have been considering the same thing. One upper builder I am looking at is Mike Milli at DTech www.dtechsuperstore.com He'll build just about anything you want. I'm looking at having him do a 16" 300 Blackout with a fluted heavy barrel and using his float tube. I need to ask him how much it weighs. High quality, super accurate, hunting upper for much less money than many 300 Blackouts on the market.

I am strangley attracted to his WSSM uppers also, but I'm not sure I want to head off that deep into the wildcat land.

"his" float tube, at least in the pictures I see on the site, appears to just be a Hogue.
http://www.getgrip.com/main/overview/ar_15.html

[Eurodriver]

I think you are overlooking the 6x45. The 6x45 meets your minumum caliber restriction and it will out perform the 300 blackout in regards to velocity, bullet drop, wind drift, and energy.

The 6x45 loaded with a Barnes 85 grain TSX at 2750 FPS is my hunting load for the 6x45. I could push it a little faster but I get good accuracy at that velocity.

OP, always consider what someone tells you and why they are saying it.

Before you decide on a caliber, take a step back and look at the big picture. See where everything is going (300BLK) The 6x45 does not offer enough over the 5.56x45 to be worth your while, it is at the bare minimum of whats legally allowed for you.

[Vash1023]

I think it's a great idea.

[BAC]

What I'm reading on the Blackout suggests Rob is right: there's no significant gain after 16" of barrel. That will save you a bit of weight where it counts for sure.

Will you be reloading? If so, you might also look at the 7.62x40, which should outperform the 300 Blackout with supersonic loads. Wilson adopting the cartridge means it now has factory support vs being a cool wildcat.


-B

[rob_s]

Anyone has a pic of some of the other rounds next to a 300 blk? 6.5xwhatever, 7.62x40, etc.

[Nightvisionary]

OP, always consider what someone tells you and why they are saying it.

Before you decide on a caliber, take a step back and look at the big picture. See where everything is going (300BLK) The 6x45 does not offer enough over the 5.56x45 to be worth your while, it is at the bare minimum of whats legally allowed for you.

And the 300 BLK offers even less. The energy of the 300 BLK is the same or less than 5.56 and ballistics are just not impressive. The 300 BLK gets incorrectly compared to the 7.63x39 quite a bit. In terms of ballistics it actually falls between the 30. Caliber Carbine round and 7.62x39.

It's sometimes hard to separate the facts from hype here. I suggest you just run the numbers on the ballistics and decide which one works best for you. The 300 BLK has a use but it is certainly not the new wonder round many here are making it out to be. It's a refined albeit lower velocity 300 Whisper. There really isn't much new in firearms technology these days. Bullet design is getting better but much of what is hyped as the newest latest and greatest is really just repackaged or refined old technology.

[okie john]

And the 300 BLK offer even less. The energy of the 300 BLK is the same or less than 5.56 and ballistics are just not impressive. The 300 BLK gets incorrectly compared to the 7.63x39 quite a bit. In terms of ballistics it actually falls between the 30. Caliber Carbine round and 7.62x39.

Thanks for your suggestion. I've had wildcats, and I just don't have time to mess with them anymore. I'll load for the 300 BLK, but it will be nice to know that I could buy and use factory loads if the ammo mule were to fall into a canyon while I'm on my way to a hunt.

Also, I think that the 5.56 NATO is adequate--although barely--for my needs. Given the fact that you can find good ammo for it anywhere, I'd use it and not look back IF it were legal in my state.

If I were to deviate from the 5.56, I'd increase bullet diameter and weight at the cost of velocity rather than keeping high velocity by dropping weight and diameter. Kinetic energy doesn't matter much in my world. I feel that KE figures overemphasize velocity, and even if they didn't, I don't trust slight differences in any method of measuring to reliably predict performance on live targets.

I agree that the 300 BLK falls right between the 30 US Carbine and the 7.62x39. I also think that's a good place to be. The 30 Carbine earned a poor reputation in combat with FMJ ammo and in the game fields with early soft-point loads. The 300 BLK has far better bullet choices and a bit more velocity, and I think that the results we're starting to see on game reflect favorably on it.

The 6.8 SPC is probably better than any of these, but seems to be turning into the 6mm Lee Navy of our day.


Okie John

[rsilvers]

And the 300 BLK offers even less. The energy of the 300 BLK is the same or less than 5.56 and ballistics are just not impressive.

No, it is more. Not sure why you think it is less.


The 300 BLK gets incorrectly compared to the 7.63x39 quite a bit. In terms of ballistics it actually falls between the 30. Caliber Carbine round and 7.62x39.

That is like saying 223 falls between FN 5.7 and 5.56mm. While true, it is a misleading example.

300 AAC Blackout has as much energy at 190 yards as 30 Carbine does at the muzzle.

While a hand-loader can push 7.62x39mm more than 300 BLK, that is not the reality of commercial ammo. The $42 a box Lapua 7.62x39mm has more energy at the muzzle than 300 BLK, but by 120 yards, 300 BLK passes it. At 300 meters, 300 BLK has 16.7% more energy.

Another example - UMC 300 BLK vs Hornady 7.62x39mm V-MAX:

Remington UMC BC 0.290 PSI, 2295 fps 16" - $12.00 a box at Midway.
Brass cased.

Hornady V-MAX BC 0.260 PSI, 2350 fps 20" - $13.80 per 20.
Steel cased.

Velocity from a 16" barrel, according to QuickLoad, 2241 fps (based on 2350 from a 20 inch barrel).

At 50 yards, the 7.62x39mm has 4 ft-bs more energy.
At 100 yards, the low-cost UMC 300 BLK has 14 ft-lbs more energy.

At 300 yards, the low-cost UMC 300 BLK has 8.8% more energy than the 7.62x39mm.
At 300 yards, the 125 Match 300 BLK has 23.1% more energy than the 7.62x39mm.


The 300 BLK has a use but it is certainly not the new wonder round many here are making it out to be. It's a refined albeit lower velocity 300 Whisper.

No, it is higher velocity than 300 Whisper(R) due to the longer throat. Think of it as 6.8 SPC-II vs 6.8 SPC.

[rsilvers]

What I'm reading on the Blackout suggests Rob is right: there's no significant gain after 16" of barrel.

There is significant gain over 16 inches:

http://img211.imageshack.us/img211/7426/300blk.jpg

http://bulletin.accurateshooter.com/2011/10/horner-wins-tactical-optics-divison-at-multigun-nationals/

[AKDoug]

"his" float tube, at least in the pictures I see on the site, appears to just be a Hogue.
http://www.getgrip.com/main/overview/ar_15.html

Uh, no, it's not a rubber coated float tube. Got to the "what's new" page and look at the tube. I have no use for rails on a hunting gun. I tried that already, amazing how much junk gets caught up in them after a day in the brush.

Thanks for the graph Silvers. Right now it's between your round and the Wilson 7.62x40.

[BAC]

Are you seeing the same graph I am Mr. Silvers? It pretty nicely shows the 16-17" range as that point where the fps gain per inch of barrel really slows down. It looks like about 100fps difference, +-10, between a 16" and 20" barrel.


-B

[rsilvers]

16 is the sweet spot. I bet if you made such a graph for 5.56mm it would show 20-24 as the sweet spot.

[BAC]

...Then the response of "no significant gains" past 16" would hold true. Not saying there aren't any, just that they aren't significant, especially in the context of a gun intended to be as light as reasonably possible.


-B

[rsilvers]

It is significant, just not worth the extra length for me.