6.5 Grendel or 6.8 SPC

[Hawk]

I got an itch that I've got to scratch.
I want to make a new AR to hog/coyote hunt with and I'm trying to decide or a 6.5 Grendel or a 6.8 SPC.
I considered the 300 Blackout and I know a few of you are loading the .300 Blackout, but I'll have shots up to 200 to 250 yards on pipe lines and tower lines (my feeder is 190 yards away in the valley and my stand is on the top of a crest with a 400 yard shot possible to the other next hill).
As I understand it, the .300 is a 100 to 150 yard cartridge. Originally the 300 Whisper, for close range, heavy bullet, subsonic, suppressed use.
I've read quite a bit on both cartridges and depending on the writer, both can exceptional in what they do.
They seem to be pretty close to the same ballistics and there may not be enough difference in them to matter.
Does anyone have any experience with either of these cartridges and cast bullets or an opinion on which one would be better?
Any help would be greatly appreciated.

PS Please bear with me. I can spell, I just can't type.

 

[Josh]

I would go 6.8 SPC between the two. If you want a bit more punch in the 30 cal platform look at the 7.62x40 WT, I have one and it is an excellent round, capable of longer shots like the 6.8 mm.

 

[RBHarter]

I'm working a 6.8 SPCII AR I also have a 7x6.8 mildcat.
Here's a link to some of my work ups for the NOE 279-124 .
http://68forums.com/forums/showthre...uot-free-quot-bullets-or-casting-on-the-cheap

This is a parallel thread with a data sheet PDF .
http://lee-loader.com/viewtopic.php?f=45&t=1133

I can tell that with the 6.8 SPCII that brass makes a big difference specifically small over large primers. The 6.8 as far as a pure cast shooter is most limited by twist . There are bbls available typically in 1-11 and 1-11.25 and a few 1-10 . If you get a 1-10 8 think you can run up to a RCBS 7mm-168 SIL . The Greenhill says 10.58 (I think that's it) so you might get lucky or not . Nominally a jacketed 130 is the upper reach for weight because of the case intrusion. The NOE Bullet occupies less case than the 120 gr jacketed and weighs in from my mould at 129.6gr of 75 / 25 WW - 1-20.
2300 fps gets you over the 1000 ftlb @ 100 yd and it should be attainable in a 16" AR . With my loads at 110 yd I was able to poke 30+ cal holes in 1/4 in plate steel ,not my goal but just how it worked out .
The 7x6.8 mildcat Carcano is capable of 2400 fps with a 27-130 paper patched at 141 gr with RL 10X . That bbl is @1-8 x 21" and has a much greater seating length allowed.

In the 1-11 twist I think the 6.8 is what I would consider an ideal cartridge for both cast and jacketed in it's platform . It's proformance can be bettered with bbls up to 22" with rifle length gas if you're interested. It offers full cases of powder for your cast bullets in the same powders as jacketed and does well from 10x to 4198 .
For jacketed loads 110 gr is about the optimum bullet weight for the highest speeds while stepping up to the 120s gets you a little more target energy out to about 250 yd .

I know zip about the Grendel although I was interested in it the 6.8 just held my interest better .

 

[Hawk]

Thank you both for your responses.
I had not heard of the 7.62x40 WT before, so that got me attention.
Doing a little searching, I found a couple of articles on it and of course, I checked out the Wilson Combat web page.
To get the same velocity as the 6.8 you have to stay in the same weight of bullet (110-125 gr). Also, I could not find a lot of reloading data. Having a wildcat/proprietary cartridge is not a problem. I've been reloading since 1975 and casting since 1985. Working up loads and experimenting with different powder and bullets is what makes it interesting and fun for us reloaders.
With comparable bullets, the 6.8 will have a greater sectional density and should penetrate better than the 7.62x40 WT, given the same bullet weight.
But, maybe a flat point in a good 30 caliber would be better and you wouldn't have to worry as much about expansion.
The Wilson Tactical would be a better man-stopper, but we have hogs that weigh 400-500 lbs. on our property.
Do you think I could get complete thru and thru penetration on a 400 lb. hog at 200 yards with the 7.62x40 WT?
I think the sectional density of the 6.8 would give it the edge for my intended purposes.

 

[Josh]

Without a doubt, the 7.62x40 was designed to be a deer rifle first. It gives real 30-30 numbers in an AR platform. If you are just looking at numbers, a 70 gr TSX from a 5.56 will be ideal for a through and through, but we all know numbers don't tell the whole story. If you are concerned about S.D. look at the Barnes bullets for the 300 BLK, they will do everything you need for any piggy. Even with the ballistically blunt Sierra 125 gr Pro Hunter making 300 yd shots on 6" steel is boring.

 

[Hawk]

Interesting... I need to do more research on this.
Thanks for the input.

 

[GSF6493]

Old post I know...but, I would go 6.5 Grendel. I have a 20" BHW 6.5 and milk jugs @ 520 yard's is getting boring. 6.8 is ok but shooting past 300 yards I would go 6.5. My favorite load is 32.3grs of Leverevolution powder and a 123gr SST @ 2650fps

 

[Ian]

I personally wouldn't touch either of the 6.5s because of the magazine issues. The Wilson Tactical is a really good solution to your problem. The Blackout isn't too shabby either, 200 yards really isn't that far for a 125-grain HP spitzer at 2K fps, and I've banged steel plates and gongs with aplomb at 200 yards with subsonic rounds which still have .45 ACP energy out that far.

 

[GSF6493]

I have not had any issues with the 6.5 Grendel magazines. ASC or Elander's. BTW I even converted a 7.62x39 20 round ASC magazine. If you don't know how to adjust feed lips then yeah guys sometimes have trouble with the 6.5 Grendel magazines.

 

[Ian]

I wasn't referring to function issues as much as expense, uniqueness, availability, all of which detract mightily from one of the AR-15 platform's most endearing qualities: Interchangeability. If you own a bunch of them like I do in several calibers that are happy in standard magazines and have just one oddball caliber requiring special, expensive, rare, finicky feeding devices, it might bother you a lot, or none, depends on your situation. Drives me nuts that my AR-45 takes special magazines that I can't buy just anywhere.

 

[Longone]

I used to shoot a 6.8 necked down to 6mm, very accurate out to 600 yards and with a fast twist you can use 100+ grain bullets.

 

[Hawk]

That's why I decided to go with the 7.62x40 WT, because of the case size and mag issues.

I couldn't be happier.

I haven't been able to completely wring out the 7.62 yet, but I have easily established a load to hunt with that shoots sub 1", 5 shot groups at 100 yards with either 110 gr. TTSX or 125 gr. Sierra Pro Hunter bullets.

I prefer the TTSX specifically designed for the 7.62x40 or the Blackout for hunting.