300 blk owners, a question for you...

[parkerdude]

+1 chaser 2332

My apologies up front, I do not own a .300blk. I have studied ballistics since 1977 though. There are no free lunches here.

If it's smaller than a 7.62 Nato, it's not, and never will be a battle rifle. Assault rifles are by design for use at shorter ranges. Pistol caliber sub-guns closer still.

The .300blk was designed to raise the bar and provide more performance in the suppressed / sub-gun environment, and an easy caliber change on the AR15 / M16 platform.

The case size is small so the powder charge completely burns in a short barrel, like 8". That's great for a round that was designed around a subsonic envelope. That is why there are no great speed jumps from barrels almost twice as long.

The .300AAC Blackout is not, and was not designed as a high pressure cartridge. Just because people are seeing how far they can push things, doesn't make it a great all around cartridge.

If you want a .30 cal. battle rifle, with some suppressed capabilities, it's not the .300blk. If you want an easy and suppressed .30 cal addition to you AR, it's a good choice.

Going to a .30 caliber, to shoot bullets light for the caliber to raise velocity, doesn't make sense. All of these changes are opposites.

Large cartridge cases don't perform well at low velocities. The .300blk was designed to one of the best at mid-range suppressed work.

Define when and how far you intend to use it, and the ballistics will guide you pretty clearly.

Maybe I just don't get it. There are some that would try to tow a boat with a 4 cylinder car. Me, I'd get a bigger car.

 

[MCMXI]

you know you can load a 308 subsonic right?

But will a .308 Win subsonic have enough energy to cycle the bolt in an AR308, M1A etc? There's a reason why .300 AAC Blackout subsonic loads are 220gr or thereabouts. If a 220gr bullet moving at 1,000 fps is just enough to cycle the bolt on an AR15, how heavy a bullet would you need for an AR308 bolt?

 

[MCMXI]

DELETE ... duplicate.

 

[Georgia45cal]

For subsonic use, what advantages does the 300 BLK have over pistol cartridges from an AR-15?

For supersonic use, what advantage does the 300 BLK have over the 6.8mm SPC?

From where I'm sitting, shooting pistol cartridges out of an AR-15 appears to be less expensive than subsonic 300 BLK cartridges as well as being more practical. Pistol cartridges can be shot out of a large variety of weapons.

 

[Trent]

Georgia -

More parts commonality between original rifle, since 300 BLK is based on the same parent cartridge (5.56), essentially everything stays the same on the rifle. Same mags, no worries about changing parts out on the lower or having to use special magazines. Same bolt/bolt carrier since the back of the cartridge is identical to 223. You can form the 300BLK brass off of 223.

So, there's not a whole lot to set up. It's easy.

Comparing it against other calibers.. different story. There's a lot you can put down the tube of an "AR-15" these days, including some big & heavy hitters (458 SOCOM, etc). I would say that each has their purposes - hell, look at Flintknapper and his piggie problem down in Texas, he puts his big bore AR to good use.

For me, parts commonality, supply of brass, supply of magazines, ability to use my Dillon 650 with a simple swap of the die holder, ability to use .308 220 gr sierra matchkings that I have a large supply of for 300 Win Mag, and other factors led me to choose it.

But I still want a big bore 458. Man has to have options... ;-)

 

[oldpapps]

Trent, well stated.

I don't see the .300 BlackOut as replacing anything.

The .300 BlackOut was designed to 'fit' and do it quietly. The 'fit' is to require only a change of barrel and everything FITS from the standard AR/M4
The quiet is being effective in powder burning to reduce muzzle noise when being fired.

This gives me a very handy and functional smaller weapon to tote around with greater punch, that doesn't break the bank to build or feed.

The .223/5.56 goes fasted and gives greater hydrostatic shock. (Have some and love them.)
The .308/7.62 is just more potent. (Have some and love them.)
The .30-30 is stuck with a big rim in a lever action. (Great round with some unique possibilities out of a single shot rifle.)
The 7.62X39 is stuck in an AK. (Personal problem with the weapon and shared with the round.)
They all have their place (but not in my safe) and do what they were designed for.

Trent wants a .458. Is that a SOCOM or Win Mag? My big boy gun is a .375 H&H. Yep, it will do the job but don't expect me to be lugging it around out on the east ridge any time soon. I'll have my little 16in M4 type in .300 BlackOut

 

[rsilvers]

6.8 is $16.18 a box for ammunition. 300 BLK - $10.36 per box:

http://www.cheaperthandirt.com/2AACO102860-1.html

And it uses normal 5.56mm magazines and has 30 round capacity.

 

[Trent]

oldpapps - I'll take both! The harder the thump the bigger the smile.

 

[68wj]

6.8 is $16.18 a box for ammunition. 300 BLK - $10.36 per box:

http://www.cheaperthandirt.com/2AACO102860-1.html

And it uses normal 5.56mm magazines and has 30 round capacity.

http://www.cheaperthandirt.com/product/2-SSA10072-SSA115OTM

Bottom line, yes, the 6.8 costs more. It should be noted though that the $16 box is for Sierra match projectiles. Dr. Roberts says: "This second generation SMK offers improved feeding reliability and much more consistent terminal performance with early yaw and ideal fragmentation. It is a good choice for military combat and non-barrier LE use."

 

[hentown]

The next time anybody here actually uses any of his rifles as a "battle rifle," how about posting the details here?? Just don't hear of that going on.

 

[farmerboy78]

Savage bailed on their 300 BLK offering because their 20" 1:10 twist barrels wouldn't stabilize 220 gr. subsonic rounds.

Most manufacturers are using 1:7 or 1:8 twist barrels. The new HandiRifle uses a 16" 1:7 twist barrel.

Savage was cheaping out by trying to save money using .308 twist barrel blanks, that's why they failed.

I beg to differ, I have a .308 win with a 20" barrel and 1-10" twist that will stabilize 220 gr bullets. Savage stopped because it wouldn't stabilize 240 gr pills which is very popular in this caliber.

 

[farmerboy78]

My .308 win is a savage precision carbine 20" barrel and a 1-10" twist and loves 220 gr sierra RN over 10 gr of trailboss. I developed this load last night and shot 1/2" group outside to outside @ 55 yds. With a 20 moa base and a swfa 10x42 ss scope. I also have a custom savage 11 300 blackout, with a 16.5" barrel (kreiger) with a 1-8" twist, 20 moa base, and a swfa 10x42 ss that loves 220 gr RN over 10.6 gr of SS 1680

 

[Trent]

Just finished the last of my build today..

300 AAC Blackout, CMMG upper, stag arms lower...

Still trying to decide what caliber to make these (also finished building these lowers today)

 

[gotigers]

jason, i just saw this thread today about a 6.5/223 cartridge.

http://www.ar15.com/forums/t_3_121/518663_6_5mm_Patriot_Combat_Cartridge__6_5_PCC__Test_subject_pics_added_on_13.html

 

[jason41987]

jason, i just saw this thread today about a 6.5/223 cartridge.

http://www.ar15.com/forums/t_3_121/518663_6_5mm_Patriot_Combat_Cartridge__6_5_PCC__Test_subject_pics_added_on_13.html

i dont mind the 5.56mm cartridge for what it is... but i dont like AR15s, so necking up a 5.56mm just wouldnt make much sense to me, most the rifles i use of this category are AKs, or similar to AKs using similar magazines.. tapered cartridges really do feed and extract a lot better than non-tapered ones do.... id be more interested in necking 7.62x39mm down to 6.5 than to persue cartridges that are designed to fit in an AR15, rather than being designed to be good

but this is off-topic, and if you wanted to discuss something with me it would probably be more appropriate to start a related topic, or IM

 

[MartinH]

300 blk

My 300 BLK is Stag lower and Model 1 upper (not 300 whisper). 16" barrel w/homemade 'quick' connect flash hider. Since the OP asked about preformance of the BLK, I offer mine.

I've fired only out to 285 yards, because thats what my range is. At this distance I'm under 1 MOA, with groups around 2"with Remington (R300AAC8) 220gr Subsonics. Remington (L300AAC2) 115gr White box loads usually do 3" or so and my hand loaded 110gr V-maxes are 1.75 to 2". I'm loading 110, 125 and 150gr bullets for supersonic and 220-240gr sub's. This carbine shoots them all well.

Loading for the 300 BLK is mostly straight forward. Data can be found on net and some manuals. Brass is available from Remington and Hornady. Reformed 223/5.56 cases work well too(subject for a different thread). The ammo feeds from regular magazines, but cartridge length is critical to good feeding. The only thing to really watch is feeding and extraction on lighter loads(auto-loaders only) Can get failure to extract and/or bolt lock open on last round.

Overall, the 300 BLK (accepted abreviation for 300 AAC Blackout) is a GREAT cartrige to play with. It is superb suppressed. It isn't for everyone. If you're in need of the fastest, super-magnum, elephant flatener, this isn't it. BUT, if you want (or need) a fun, ACCURATE cartridge, that's easy recoiling, low muzzle blast, this might be your new favorite. This is especialy true if you have/want a AR, M-4, M-16. A barrel is all it takes to get into it. But be prepared to be hooked. I am!

 

[Jon Coppenbarger]

Mine is a S&W ar in 300 blackout 16" and the rifle also is in realtree camo. Have not fired it yet but really thinking about doing the paper work for a sbr and can.
Have a few friends with different rifles in the cal. and they like it.

 

[C-grunt]

hmm... lets see... 7.62x39mm 123.5 grain, 2,640fps, 1,810 ft/lbs of energy

.300 aac blackout 125 grain, rougly the same ballistics coefficiency 2,215fps at 1,360ft/lbs... yeah, these are soooooo ballistically identicle

do you people just assume that because the actual projectile is roughly the same, that ballistics would be somewhere close?.. its nothing but a slightly glorified .300 whisper

What 7.62x39 ammunition are you using that is getting over 2600 FPS out of a 16 inch barrel? The fastest load I could find online was just over 2400 FPS.

 

[justice06rr]

I think Jason just has something against AR's, or anything related to them...

The 300BLK is great for its intended purpose. It is not an x39AK or a 5.56, so please dispense of some of the bias. 300BLK is what it is, a .30cal solution that is interchangable with AR parts save the barrel, and provides great ballistics within its intended range. Its not meant to replace 5.56, 6.8 or 7.62x39.

What is hard to argue is its increased popularity as of late.

 

[mastiffhound]

Not this again. I'm sure everyone that has a 300BLK is happy with there purchase and defending it seems like the thing to do. I looked at it awhile back and came to the decision it won't work for me. I have no need to suppress my rifles. I will put this into the perspective I used.

MK262 77 grain 14.5" barrel from memory is something like 2680 fps, which translates to 1225 ft lbs or so.

300BLK 16" barrel 125 grain 2220 fps or so with 1360 ft lbs or so ( wiki )

300BLK only has a advantage of 135 ft lbs. Make that 14.5" barrel 16" and we are even closer, maybe dead even.

Am I shooting suppressed? No. Does it make sense for me to pay money for a different calliber and the barrel to go with it? My common sense tells me NO. Will the 300BLK reach out to the ranges the MK262 will? Maybe, but probably not, unless you can dial enough drop on your scope.

My conclusion brought me to this, unless I'm suppressing 300BLK it is useless to me. Note that this is not a 20" barrel, that is the argument I always see. If you sell 300BLK barrels and ammo then I would sell like mad like every other guy, that is what business is about. This is me, not any or everyone else. I just can't justify getting this round when I can get comparable performance from a round I already buy and handload for.

 

[hentown]

Yep, my memory failed me. It was .4", accomplished by two passes @ .2" each.

 

[Walkalong]

What is hard to argue is its increased popularity as of late.

Yep. I am only shooting supersonic in mine and I love it. It shoots the 155 Gr A-Max very well (Under 1 MOA if I do my part), and for cheap plinking I am using 147 Gr pulled bullets. I could care less how it matches up mathematically with similar use calibers. With the 155 Gr A-Max it can be useful for defense out to 250 or 300 yards easily, and with 147 Gr pulls, it can be a fairly cheap plinker. Cases are inexpensive as well, and even cheaper if you make your own from .223 brass.