.300 BLK or 6.8 SPC?

[Idaho45guy]

I have a tricked out old('99) Bushmaster V-Match Carbine in .223 set up for the zombie apocalypse. I was looking to buy a new upper for it in one of the "thumper" cartridges such as 450 Bushmaster or .458 SOCOM. Then I discovered that the uppers are usually around $700.

Was at the gun shop today and they were selling Ruger AR-556s for $599. Bought one.

Now I'm thinking about buying an upper for it in a heavier cartridge, but not a thumper class cartridge. Obvious choice is the .300 Blackout for something heavier hitting, cheap, commercially available, etc.

I've also heard good things about the 6.8 SPC but could not find a single thread on it here. There is also the 6.5 Grendel but it seems even more scarce than the 6.8 SPC.

I would be going with a 16" barrel and rifle would be used as primarily a truck gun with iron sights. More of a SHTF rifle than anything else. I have plenty of bolt-action hunting rifles for deer/elk/bear and no hogs up here.

Seems the .300 BLk has plenty of following for reloading and even casting boolits for it. How about the 6.8 SPC?

[Hamish]

Cost is much lower for the 300, parts and brass. If you're casting for thirty cal. chances are you have a mould that will work.

If you decide 300 BO, weigh the twist rates to fit your requirements.

[2wheelDuke]

It really depends on your needs. You probably know all the pros and cons of 300blk by now. Parts, components, ammo, etc. are pretty cheap and readily available. Mostly because of the .223 parent case. But it is a close range round, even supersonic. For where I live, that's really not a deal breaker.

6.8spc is a better round for longer range as it has a bit better reach than the blackout. That comes at the price of brass you can't form from readily available range pickups, and it takes a special bolt and magazines. Cast isn't unheard of for 6.8spc. I've seen group buys on here for custom 6.8 molds. You may get better info on a forum dedicated to the 6.8spc. But on the 300blk forum, lots of guys refer back here for cast boolit info. You may have a tough time with the 6.8 with cast because it's meant to run a lighter boolit pretty fast, and the twist rates usually correspond to that.

The Grendel is even more specialized of a beast. It's a great round, but it's a necked down 7.62x39. That brings it's own issues in the AR-15 platform. There's not much material left on that bolt face IMO, and there's the case taper to contend with. I don't think it's much of a cast shooter at all from what I've seen.

If you're talking about an iron sighted truck gun, I'm thinking that 300 blackout will be good enough.

[Harter66]

NOE has a dedicated bullet for the 6,8 that gets run at least a couple of times per yr .
6.8 is a down fall of the cartridge but it and it's parent is more available than it appears at first glance .
It's a 270 cal ......... That is a handicap sort of . Jacketed bullets are available from 75-130 gr for the 6.8 .
Yes it takes a special mag they're the same price or maybe a buck more .
You can't accidentally chamber a 6.8 in your 223/556. Like a 300.
Blackthorneproducts.com has a complete kit rifle less lower receiver under $475 this week in each cartridge. The 300 is more than the 6.8 they use Wilson and Mossberg bbls.
The 1 I shoot gives me 2050 fps with NOE 279-124 @ 129 gr checked and lubed seated to 2.285 for the AR Stoner mag length with 23.3 gr of H322 sized at .280 for check seating . It gives an inch and half at 100 and punches holes in 1/4" steel plate . I run 75/25 WW-1/20 water cooled . FC brass .
The FC 115 fmj , Hornady 120 sst factory loads gave me 2.5 inches out of the box from the 1-11 , .270x.277 sixteen inch bbl . I changed the A2 fore stock and gas block to a free float and low profile and closed the groups to under 2" .
This is a dedicated 6.8 forum . Several suppliers are active members .
http://68forums.com/forums/forum.php

This is a thread else where about the whole trip from day 2 to final field ready loads .
http://www.lee-loader.com/viewtopic.php?f=45&t=1133
Also
http://68forums.com/forums/showthread.php?57557-6-8-and-quot-free-quot-bullets-or-casting-on-the-cheap

I am not a 6.8 fanboy . I hold no grudge against any of the other AR 15 etc cartridges . The 6.8 just works .

I also shoot a 7x6.8 , a straight neck up of a whopping .007 . In an effort to get subsonic because I was bored I guess I found a 285-150 NOE could be run subsonic but it took less than 4.0 Unique for it to happen . Same load with with a 7mm-168 SP also worked in a bolt gun of course .
This is a very efficient cartridge . As an all around cartridge I would recommend the 6.8 SPC in a 6,8 SPCII platform . It's leade and throat changes that allow higher performance for the hand loader and generally speaking the industry standard over the SAMMI drawing .

[Scorpion8]

The answer to your question should be, at the end of the world, drive to the most hicktown hardware store you can find and see what ammo they will have. Most likely neither of those two. But they will have Soviet/Combloc 7.62x39 or plain ol' .308 Winchester/NATO. I'm not a fan of rifles in "specialty" cartridges that I can't find en-masse in remote places.

[Harter66]

That would be why the OP has a 223 .

[pugjunga123]

I vote 300BLK. I just built one on left over parts. I'm happy

[Harter66]

For $625 you can try them both .

http://blackthorneproducts.com/cart/index.php?main_page=product_info&cPath=6_17&products_id=782

http://blackthorneproducts.com/cart/index.php?main_page=product_info&cPath=6_17&products_id=713

[Idaho45guy]

Great responses and info! This place always delivers!

[Omega]

I like the 300BLK, mostly due to the component aspect of it. I also have a .277 WLV which works on the same principle as the 300BLK, just a barrel change. Using the 5.56 case with a .277 bullet gives you near the 6.8 SPC performance with readily available AR parts.

[dk17hmr]

I prefer the 6.8 in rifle length configurations over the 300blk but prefer the 300blk in SBR/pistol configurations over the 6.8.

300blk is easy and fairly main stream for loading and shooting cast in.

I use my 6.8s more but don't shoot cast in them.

[Idaho45guy]

How much potential is there in reloading the .223 with heavier bullets and more oomph?

[dk17hmr]

How much potential is there in reloading the .223 with heavier bullets and more oomph?

77s in a 223 are good and I really like them for several things. Honestly if you want heavier than about 62gr set up a 6x45.....which is about the best 223 based AR round out there.

[Lead Fred]

We have two 300BOs, and will be making a pair of sub-sonic uppers.

If you go 300BO, figure out if you want a heavier hitting 223, then go carbine length gas system.
If you want subsonic, go pistol length gas system.
Neither will do as good at the other, as the one meant to do the mission.

Right now building a carbine length varmint gun is cheap. Everyone seems to be going subsonic, so Midway and others were dumping good carbine barrels dirt cheap.

There are several shooters here, that have tried subsonic with carbine gear. None get them to cycle while remaining subsonic.

On the other hand, our main food is 147gr M80 ball. 1700fps & 30 of them makes a decent 100 yard lead spitter. 125gr Speer grenades do 2150fps, and 110gr can do 2300fps. Both the 110gr and the 125gr use the same load, but the 125s deal 3x the damage. Go figure.

I know nothing of 6.8 SPC, dont even know if its SAMMI spec or still wildcat. Im loaded down with 30 cal pills, and cast them.
I even have a mag full of 165gr Ranch Dogs. I doupt they will cycle, but they will do 1900fps.

[osteodoc08]

The 300 BO really shines with either 110/125gr class or heavy subsonics.

I have three 300 BO AR's.

One is a 16" Sig M400 Hunter that has a match grade stainless barrel with Gieselle trigger from the factory and is a ragged hole tack driver for me. I plan on using it to hunt some with this year and is a 150-200 yard gun.

Another is a Sig Pistol with Sig Brace. What can I say other than it is very short, compact and looses little velocity over a longer barrel.

The other is a 18" barreled plinker from PSA that crunches through plinker fodder made with M80 pull downs and chews through them like skittles.

Ive really fallen for this little gem of a cartridge. The Pros and Cons are up to you. It will
never be a long range heavy hitter, nor was it designed to be.

[rwadley]

The Grendel is even more specialized of a beast. It's a great round, but it's a necked down 7.62x39. That brings it's own issues in the AR-15 platform. There's not much material left on that bolt face IMO, and there's the case taper to contend with. I don't think it's much of a cast shooter at all from what I've seen.

The Grendel is actually a necked up 22 PPC (based on 220 Russian). It doesn't have a lot of body taper (about a quarter of what 7.62x39 does).

[Moonie]

The only AR's I have are 300 BO and 6.8 SPCII. The 6.8 is a great deer gun, the 300 gets used alot more often because it is just alot of fun, and yes, I do have a can. I also have a 7.5" threaded Encore barrel in 300 BO that the can usually stays attached to.

You really can't go wrong with either, just depends on your needs. Brass for 300 is easy to find, not so much for the 6.8.

[Moonie]

I have a son with a very expensive 6.5G setup for long range competition an a 300 BO SBR, the 300 BO gets alot more use than the 6.5G.

[longranger]

Osteodoc08 said it best, 300BLK "I've really fallen for this little gem of a cartridge". Amen. Darn thing will shoot any .30 cal. projectile.

[kawasakifreak77]

If you want a silncer, blackout.

If not, 6.8

[Texas by God]

At our deer lease we have ARs in .5.56, .300BO, 6.5Gren, 6.8SPC, and 7.62x39. These are our Feral Hog guns. They all work. IMO the .300 is fun and easy right away- but I'm the only reloader. I like them all. I will warn again to KEEP .300 Blackout AMMO AWAY FROM 5.56/.223 RIFLES BECAUSE IT WILL FIT IN THE CHAMBER. BE SAFE!!! Best, Thomas.

[roysha]

I like the 300BLK, mostly due to the component aspect of it. I also have a .277 WLV which works on the same principle as the 300BLK, just a barrel change. Using the 5.56 case with a .277 bullet gives you near the 6.8 SPC performance with readily available AR parts.

Indeed it does. I have an XP-100 chambered for that cartridge and it chronographs, (from a 14" barrel) just shy of 2225fps with Sierra 130 SPT. Downside is that it is a wildcat, thus a pure handload situation.

I don't know what a .277 WLV is but before I rechambered the XP it was a 270-221 and chronographed 1850fps with the same bullet and would put them into an inch at 100 yards with minimal effort on my part.

[dogmower]

I bought a 6.8 upper a while ago, before the 300 bo came out. had a bit of buyer's remorse, thinking "why did I buy this", "i don't need it", etc. I almost sold it when the first jacketed handloads I shot were 2 inches plus at 100 yards. then, I tried a load it liked, and wow! quarter inch groups all day long and more power than the .223 to boot. this is a plain jane upper (I don't remember the make) with a carbine standard weight barrel.
when I got into casting, I worked up loads for 115 and 130 grain cast boolits. shoots into apple sized groups at 200 meters all day long.
I haven't played with the 300 bo yet, but to my mind, it's best served if you are looking to shoot suppressed. otherwise, why not 7.62x39? that cartridge, in an ar platform, is WAY more accurate than most people realize. we shoot at 24x18 rams at 500 meters, and my ar will drop them in regularly (as long as the wind cooperates). ammo is still relatively cheap and the mags I have are reliable. I've been working up cast loads for the ar in 7.62x39 and so far it looks promising. using a lee 165 grain GC, PC boolit, sized .309 over 23 grains of aa 2230.
BTW, don't count out the 458 socom. I got a great deal on an upper for my ar, and I LOVE it. very accurate, powerful, and relatively cheap to shoot if you cast. That's a real thumper.