Need Help On A 6.8...

fordnut

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Thinking about a 6.8 upper for one of my AR's...I no nothing about a 6.8...please give me Pro's and Con's...

I wanted to go .300 Blackout, but, got a chance to trade for a complete upper in 6.8...just don't know about the round...

Steve
 
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I don't claim to know a single thing about 6.8 SPC except that the owners and adherents to the round are maniacal about it. Talk trash about the round to a 6.8'er and you'll get an earful, if not a fight. My contribution to your question is this: consider why the 300BLK was designed; to be able to fire a 30 caliber round that carries as much or more terminal energy as the 7.62x39 AK round using existing 5.56 lowers, BCG, and 5.56 magazines with NO reduction in magazine capacity with only a barrel change! Also because of the heavier bullets available in 30 cal, 300BLK performs extremely well suppressed subsonic. I have no doubt 6.8 is an excellent round, but if you have the chance to buy an upper for an existing AR lower, I don't think you can throw 6.8 into AR lowers, BCG's, and mags like you can the 300BLK without rebuilding the entire gun. Just something to consider.
 
Disclaimer: I don't own an AR at all right now.

Here is what I have seen in my research of AR-15's
The 6.8 brass is expensive. Its parent casing is the 10mm magnum, which I can honestly say I have never heard of (granted, this doesn't mean much).
It shoots .270 bullets.
They say it hits like a .308 out to 200yds.
It doesn't use standard AR-15 magazines. Apparently it will crack pmags if you put more than 5 in one.
There are something like 5 specs for it, though only two are widely used now. If the upper he is trading isn't a spec II, don't trade for it. The original spec is under powered.

This is what I have seen from 6.8 fanatics:
Anything else shot out of an AR-15 will bounce harmlessly off of the target. Especially the 300 aac blackout. At any range.

Disclaimer 2: I have a 5.56 and a 300 AAC Blackout on order.
 
If you got the impression that brass/ammo was expensive from me at the 'fest, that's mostly because I'm poor at the moment and have a hard time affording .22LR much less real rifle rounds. There was a reason I only had 20 rounds for my Mosin. :/

I picked the 6.8SPC as my alternate caliber AR after about 3 years of research... and, I wasn't in a real hurry. The 6.8 parent cart. is a Remington 300, which is obsolete. The 10mm Auto/.40 use the same base and rim dimensions, hence the confusion. There are several total specs: SPC, SPCII, and 6.8x43. The last two are virtually identical. The main difference is in the length of leade, with the earlier chamber dimensions not allowing higher pressure ammo like Hornady's tactical loads. Not a real reason to reject an otherwise good deal, since 15 seconds with an SPCII reamer will fix the problem. Look for something over 1/10 twist. Most like 1/11 or 1/12.

To switch any caliber AR to 6.8, you need:
new barrel
bolt (carrier, extractor, etc can stay the same)
magazine* (see below)

Pros:
legal to hunt with just about anywhere
hits like a 308 out to 200 yards
under 200y basically same ballistics (for scopes/sights) as 5.56
light recoil
prices of ammo coming down**

cons:
expensive to shoot compared to surplus 5.56
can't use standard NATO magazines without problems
... I fail to see many more problems. :)

*5 and 10 rounders just need a new follower. 20-round and 30-round NATO mag bodies allow the stack to skew, so you need purpose-built mags, that give you 15 and 25 rounds respectively. So if you're looking for a SHTF loadout you'll be carrying less ammo total... and kinda creepy. PMAGS I have heard the 5-round rumor, and since I was using a borrowed mag I wasn't about to test it.

Having said that, mags vary in price from ASC/ AR-Stoner at around $15:
http://www.midwayusa.com/product/776142 ... teel-black

to Barrett true 30-rounders at $40
http://www.midwayusa.com/product/163532 ... ound-matte

I've got 5 of the C-products 25 rounders (same as AR stoner) and they work flawlessly. When I remember to bring them to the range. :)

**Like all commercial (as opposed to surplus) rifle ammo, prices are too damn high. 6.8 has actually come down a bit since introduced; you can get Hornady 110g vmax plinking/varmint/HD ammo for about $17/20. More significant hunting or tactical ammo can be had for more; I think the most expensive I've seen is a solid copper load at about $45/20.

Personally, I reload roughly similar to the Hornady round (maybe a little hotter) and it costs about $0.47/ round including using a powder which ain't the cheapest (Benchmark) and CCI 41 milspec primers. Reloading is the way to go - and it's an easy caliber to reload, if there is such a thing. Decap and size, trim, clean, prime, charge, seat, crimp. In a progressive press I could really churn them out. As it is, my single-stage press allows me to do a couple hundred a night, start to finish.

Summary: Good hunting round for small game up to whitetail and feral hog (I know several hunters of both that use 6.8). Devastating HD round. More expensive than surplus ammo like 5.56 or 7.62 nato. Probably won't work as well with a suppressor as 300BLK. Hits but doesn't kick like .308.

IMHO - if you want a higher energy round (than 5.56) that is cheap to shoot, get an upper and mags in 7.62x39. The derivatives (6.5 Grendel and others) are more expensive, but might be right for you if you need that round's specific ballistics. 6.8 is a great intermediate round - between 5.56 and its questionable terminal ballistics (especially out of short barrels) and 7.62N with its weight and kick.
 
Guys...Thanks for all the info. I need all the help I can get...

I tried the 7.62x39 upper trick...I probably spent $1500.00 trying to get that dog to hunt////THEN, I traded all the 7.62 stuff(AT A great lost in cash outlay) for .223 stuff...I just wanted something that would run...No more 7.62 nightmares for me...

I have a Stag lower, and, the upper I have a chance to trade for is also Stag...but, all I know now is it is a 6.8 SPC...

I might just go 300 blackout and forget it...I know Jeff at P-1 Ammo has a great new Mosler tipped 300 Blackout that is running great...

Maybe that is where I need to be...

Steve
 
I was hoping you'd would show up with some better facts on the 6.8spc than I was able to provide.
rotarymike said:
The 6.8 parent cart. is a Remington 300, which is obsolete. The 10mm Auto/.40 use the same base and rim dimensions, hence the confusion.
Thanks, figured I had that wrong. Too much reading at work and recall can get jumbled ;)
On a side note, did you get your mosin's bolt to behave?
 
Haven't shot it again, but I did run the buffer wheel around the rim until it felt nice and slick. I also wire-wheel polished the rest of the bolt. That + teflon/moly mold release agent as lube and the gun does cycle smoother. Alas, no more 54R ammo for now.

I keep getting interest from legal clients, but no one wants to pay for it, even at sharply reduced rates. So until I can fix that, my gun budget really sucks. Guess I'll have to work on reloading the 1000+ 9mm range brass I've collected. :roll:

I've reloaded what I shot at 'Fest in the 6.8, and actually picked up 50 more brass so I reloaded until I ran out of powder. If you want to shoot it again to decide, or just look it over, and you're in the lowcountry LMK.
 
Fordnut:

Are you looking at auto cycling an AR? Or did your 7.62x39 upper just not run well in semi either?

My upper is from Rock River and I can't be happier with it. I would have preferred to get the free float tube and folding front sight at time of purchase but didn't have the $$$ then so I did those myself. IMHO, key to running the 6.8 is midlength gas. Carbine length apparently leads to hangups in the short buffer tubes of a collapsible stock and causes short stroking.

Were I to look at a 6.8 in a shorter barrel than 14", or with a carbine gas system coupled with collapsible stock, I would look at an M16 bolt carrier (solid rear for more mass) and maybe an Enidyne hydraulic buffer. Or you could get an adjustable gas tube from Brownells.

Lower really shouldn't matter unless you're thinking about full auto in some form. In which case, I'd talk to Henry and see how he got his registered DIAS setup working - my experience with FA guns is M16A2 from back in the day. And the occasional shotgun with a broken sear.

Also - same offer to inspect/shoot my setup applies. I'm in North Charleston, so Boggy Head/Twin Ponds are equally far. Trader world doesn't like my long guns, and ATP is ATP.
 
I am a poor old retire...can't afford full up and not much of a suppressor fan...I just want something that runs...

I have the Carbine gas system, but, the M16 bolt set-up...I use the folding stock...That was the same set-up as I had with the 7.62.

I had so many feed issues with the 7.62. I had 6 mags and none of them would run. I even spent $85.00 on a new Frankenstein .223/7.62 mag from an auction site....It was brand new in the package...Never got it to run...

Steve
 
fordnut said:
I am a poor old retire...can't afford full up and not much of a suppressor fan...I just want something that runs...

I have the Carbine gas system, but, the M16 bolt set-up...I use the folding stock...That was the same set-up as I had with the 7.62.

I had so many feed issues with the 7.62. I had 6 mags and none of them would run. I even spent $85.00 on a new Frankenstein .223/7.62 mag from an auction site....It was brand new in the package...Never got it to run...

Steve
You could take the trade. if you don't like it, sell the 6.8 upper and buy a 300 BLK uppper with the sale proceeds.
(I'd put it for sale on one of the "we <3 6.8SPC" sites, just don't tell them you're selling it to get a 300 AAC blackout.)
 
6.8 is a fun round to shoot for sure...
However, more development is being done by military teams on the 300 BLK. Piles of brass from training blanks are currently being converted to 300BLK at Ft Bragg. Tons of brass is available and only a barrel change to existing equipment to shoot the caliber.
 
I agree with Paco. The 6.8 isn't going to lose value; a complete upper is worth at least $500, perhaps more depending on particulars. You can always use it to trade later.

What's the parent cartridge of the .300BLK?
 
rotarymike said:
I agree with Paco. The 6.8 isn't going to lose value; a complete upper is worth at least $500, perhaps more depending on particulars. You can always use it to trade later.

What's the parent cartridge of the .300BLK?
The parent cartridge of the .300BLK is the .223 Remmington. You can also form it from 5.56 NATO brass.
 
Looking at both on Wikipedia (I know, I know) the 300BLK has a lot less muzzle energy. Suppressed it has less than a 9mm, if I'm reading that right.
 
Just an FYI from my experience with 300blkout. Make sure your upper has the M4 feed ramps. When I first built mine I was having feed issues. Turns out what the upper that I bought didn't have the feed ramps. Not to mention it was out of spec in a lot of areas. The problem was that the round would hit where the feed ramp should have been and just stop. Replace the upper and not a single miss feed after 100 rounds.
 
(beware thread drift.....)

guy in Savannah had a Ruger Piston 6.8 he was selling CHEAP. i could not get over the 6.8 increased cost, and having the increased complexity of having 5.56, 6.8, and then maybe a .308 in a few years.

why not go full .308 / AR-10?

what is the per round cost, if you buy in bulk (say ~500 at a time, gun shows?) for each?
i try to buy 5.56 at $150~175 for 500 rounds/
 
rotarymike said:
Looking at both on Wikipedia (I know, I know) the 300BLK has a lot less muzzle energy. Suppressed it has less than a 9mm, if I'm reading that right.
The 300BLK's energy information is listed ft/lbs then (Joules) in the table, but for the 9x19mm its listed as Joules then (ft/lbs). Easy to misread.
So the subsonic 300BLK has more energy than all the listed 9mm, except +P+, with the benefit of actually being subsonic.
04ctd said:
(beware thread drift.....)
I suppose we should make a new thread then.
 
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