Why 300 BLK? This is why.

[nolwark76]

So I got bored today and nerded out on the JBM ballistics computer. Wow, very interesting. If someone could tell me how to take an Excel spreadsheet saved on my PC, I'll post it. Now granted my numbers were swag/online posts of others and not my actual data over a chronograph.

Check this out:

5.56 16" barrel shooting Barnes 55 grain TSX ammo at 2950 mv/ 1074 me. Bad mamma jamma right? Yeah, up close. At 300 yards the MV is down to 1733 which is below the minimum expansion velocity listed so it's now no different than any other FMJ rifle bullet and will tumble or deform a little but not do it's TSX thing. At that velocity the energy is down to 366 ft/lbs. No, I wouldn't want to get hit by that.

Then I looked at a 9" 300 BLK upper firing a 220 grain OTM SMK bullet subsonic. Guess what it does at 300 yards? With a starting MV of 1000 fps at 300y its down to 923 fps (very cool that fat and slow doesn't slow down much) but the energy is 416!!!

If you have a 16" barreled .223 and are using 55 grain ninja commando ammo and need to take a shot at a bad guy at 300 yards or more, you might want to think about switching to a 9" 300 BLK subsonic instead. Oh yeah, use a LeHigh Defense expanding subsonic and you're even further ahead of the game.


I also looked at the energy of a .22LR JHP from Federal listed on Ruger's website. A 30 grain JHP going 2200 from a 20" barrel (wow that seems fast) will have only 200 ft/lbs of energy left at 50 yards. I don't want to get shot by a .22LR at 50 yards. It could kill you or at least really hurt.

I then looked at the .380 ACP pistol round. I remember reading an article about a guy using the new Kahr .380 to hog hunt with some JHP and had a guy with a 12 gauge next to him if it didn't kill the boar. He snuck up on a pig that weighed in at 220 lbs and killed it from about 10ft away with a .380 ACP. Holy crap!

So looking at that, I looked at where the 5.56 and 300 BLK dropped below 200 ft/lbs of energy.

10.5" 5.56 with 55 grain TSX will drop below 200 ft/lbs at 400 yards.
9.5" 300 BLK with 110 Black Tip will drop below that at 800 yards!

16" 5.56 with 55 grain TSX will drop below 200 ft/lbs at 450 yards.
16" 300 BLK with 110 gr Blacktips will drop below that at 850 yards!

Now the 5.56 does much better with heavier bullets such as the 77 gr SMK than with the lighter 55 gr TSX. Ok, ok let's give the 5.56 it's best chance and use a Mk12 Mod 1 from Lone Survivor with Mk262 ammo leaving the muzzle at 2800 fps and ME of 1348.

Then lets shoot 125 gr OTM from a 16" 300 BLK. MV-2400 but ME of 1353- basically the SAME as a Mk12! At further ranges the Mk12 Mod 1 has the edge with it's Mk262 ammo. However the Mk12 drops below 200 ft/lbs energy at 900 yards while the 300 BLK with 125 OTM doesn't do that until 1000 yards.

And oh yeah, the 300 BLK will cycle readily available subsonic ammo that is easy to get to run where as an 18" 5.56 will have serious trouble, even cycling sub sonic ammo from a 16" 5.56 barrel is specialty ammo or at least not nearly as easy.

Why does it matter? Well it just confirms what we've all been told about the 300 BLK. For energy on target I pick the 300 BLK. If you only want to punch holes in paper then the 16 or 18" 5.56 will have less drop and wind drift in a 10 mph wind than the 300 BLK.

It was fun nerding out today and confirming why I really like my 300 BLK rifles. No, I'm not getting rid of my Mk12 Mod 1 or Rock river .223 but I just find myself wanting to shoot my BLK much more than those two!

[Sharkbite]

Wow....that surprised me

I love my blkout, but id have put money on the supersonic 223

[Piep]

Wow....that surprised me

I love my blkout, but id have put money on the supersonic 223

I belive we know who was the one that voted 5.56.....lol

[nolwark76]

Ok, who did that? Just kidding. Yeah, I had to re-check the table a few times. Nope, it's right.

The 300 BLK is not better at long range in the wind (drop is dialable- wind is like reading voodoo) like the Mk12 but then again, if you are shooting at 600+ or definitely 800+ yards, why not use a .308?

For the foreseeable future, .223 will always be more plentiful than 300 BLK ammo. Got me there. And then what?

I might have to re-think not putting a low power variable scope like a 1-6 power on my 9" SBR. Know the drop for subs and bam, drop a 220 SMK on something 400 yards out all quiet like and it's like a .45 FMJ at the muzzle but in a longer and pointier shaped bullet that will probably penetrate better and tumble with a greater wound cavity. I'm just guessing on that but the ballistics are comparable.

[Guest762]

Being highly educated in the realm of physics (one year in high school )
The first time I heard the quote "you can't replace mass with velocity"it made perfect sense to me.

[nolwark76]

I guess that's the lysdexic side of me. I had to re-read that. I read your quote backwards.

[Black Friday]

Being highly educated in the realm of physics (one year in high school )
The first time I heard the quote "you can't replace mass with velocity"it made perfect sense to me.

Hell, I learned that in beer drinking 101 school. Has something to do with shotgunning a beer.

[mrgein]

concerning excel, as long as all you want to do is let people view it, just maximize the spreadsheet do a shift+printscreen and then paste into paint, then post it.

[blaster]

suprised (pleasantly) me. I voted for the 5.56.

[cutter_spc]

I also looked at the energy of a .22LR JHP from Federal listed on Ruger's website. A 30 grain JHP going 2200 from a 20" barrel (wow that seems fast) will have only 200 ft/lbs of energy left at 50 yards. I don't want to get shot by a .22LR at 50 yards. It could kill you or at least really hurt.

Is this some new 22LR round I haven't head of? 2200 FPS? JPH? In a 22LR? Man that's 22 Mag velocities.