6.8SPC making a surge....

[MEHavey]

the 6.8 SPC aficionados are touting several new SSA (Silver State Armory) ammunition loudouts -- particulary the heavies:

http://www.ssarmory.com/6.8_spc_ammo_140gr_VLD_Berger.aspx

On paper it looks astounding -- that they could get those kind of velocities from a case that not only contains less powder
in an absolute sense (at least 1 grain less), but is also far less efficient -- and still stay within pressure limits. In effect it matches
or beats the Grendel from muzzle to the 1,000 yard game.

http://thefiringline.com/forums/showpost.php?p=5155440&postcount=45

There's little question that us handloaders could come up with recipes that pull ahead again, but we would be playing in the dark
as far as true pressures go since we need to stay under 55,000psi to save the bolt lugs.

Any thoughts on the commercial guys working on the next phase of Grendel heavies -- and finding tested solutions within the req'd
(and tested) pressures?

[Bwild97]

"MEHavey"

In effect it matches or beats the Grendel from muzzle to the 1,000 yard game.

What loading is this? I went through all of SSA's loadings for the 6.8 SPC, using claimed MV with the "SHOOTER" app on my android phone, and nothing was able to match the Grendel at 1000 - 1200yds. The only advantage the 6.8 SPC has over the Grendel is muzzle velocity with light pills out of a short barrel.

And those SSA loads are using a non-standard COAL of 2.300" and will not function in Barret rifles or spec 1 chambers

Here is a look at what you could expect at 1000yds from a handful of projectiles (hand loads) pushed from a 20" barrel with optimistic MV's.

DA 1209ft 8mph winds @ full value

Muzzle Velocity / Velocity / Energy / Elev. MoA / Wind. MoA
/ / /
2800fps /

107g SMK /1175fps /328 ft-lbs/ 34.2 / 7.8
108g L scen /1259fps /380 ft-lbs/ 33.4 / 7.4

2600fps

123g Amax /1244fps /423 ft-lbs/ 37.3 / 7.3
123g L scen /1273fps /442 ft-lbs/ 36.4 / 7.0

2550fps

130g Ber /1251fps /452 ft-lbs/ 36.8 / 6.8
130g Norma /1280fps /473 ft-lbs/ 37.1 / 6.8

2450fps

142g SMK /1266fps /505 ft-lbs/ 39.5 /6.7

[Grimmy]

Not to stir the pot but few Grendel shooters are running 16" guns that are intrested in the long range shooting. I own a 6.8 and a 6.5. The 6.8 is a 16'' and the Grendel is a 19.5 and in hind sight I wish I would have gone to a 22" or 24". I myself veiw my Grendel as a medium range rifle and the 6.8 as an all around weapon with medium range options. The Grendel is a heavy pig that shoots very well but the 6.8 is more versitile, I shoot it at my tactical course and also at medium range. If I had to pick one do all it would be my 6.8 if ammo supply would limit the usefullness of the 6.8 platform. I love the capabilities of the Grendel for long range. For short range under 300 yards I would pick my 300 sonic blackout. To me each has it's own applications where it shines. I would have to agree with Bwild97 on the velocities and he has provided us all with a great amount of testing info. And last but not least my 6.8 has never shown the accuracy potential that the Grendel has. My 300 out shoots my 6.8 which is disappionting.

[mongoosesnipe]

It is also a load that oes not chamber in all guns and it long to the point of only feeding out of one specific mag and it does not so much beat the Grendel as much as it matches it

[MEHavey]

You probably want to look at the curves at:

http://thefiringline.com/forums/showpost.php?p=5155647&postcount=47

When lines overlap that much at long ranges, they are statistically identical

For that matter, look at the whole developing discusion string:

http://thefiringline.com/forums/showthread.php?t=495697

(Ignore the startup concerning the AK -- it quickly became a Grendel discussion.)

I'm a dyed-in-the-wool Grendel fan/owner.
But SSA has pushed the 6.8 envelope way beyond expecatations, and I'd like to see what lies ahead if Grendel played out the next steps using it's advantages

[Drifter]

IMO, the key factor is centered around modern powders being tested and applied to each cartridge.

Generally speaking, I see the 6.5 as always being ballistically superior to the 6.8 at extended range. The 6.8 might get a boost from a new load, but there's no reason that the 6.5's performance can't be advanced in similar fashion.

With 6.8 ammo seemingly being SSA's "bread-and-butter", it should be no surprise that they developed something new that advances the cartridge to some degree.

Perhaps Hornady will eventually develop some Superformance-type loads for the Grendel. But in the meantime, I'm sure handloaders will continue experimenting with the newer powders.

[Bwild97]

[Drifter]

Ok, so in as close to an apples to apples comparison as I could come to, between the 6.8 SPC and the 6.5 Grendel, both pushing 140g class projectiles ...

6.5 G doesn't need a 140gr bullet to exceed the BC of a 6.8 140gr.

.264 130gr Berger BC is .552, while the .277 140gr's BC is .487.

Even the .264 120gr Berger has a BC of .453, which is probably more in line for comparison purposes. And, of course, the 6.5 120gr can be pushed quite fast with modern powders.

[Bwild97]

Yes, you are right, but I was only comparing them by MV, Barrel length, projectile weight. Adding Projectile BC (which the 6.8 fanboys hate to talk about) to the mix adds oranges to the external comparison.

The whole comparison thing makes me laugh, after reading through a thread on the 6.8 forums a few of the guys who are feeding the 140g Berger to their rifles can't get a respectable group at 100 yds. After a little searching I was unable to find any posted groups with the 140g Berger that were acceptable.

[bwaites]

Mostly because they slowed the twist and lengthened the throat to get high velocities with the lighter bullets, and now they don't have enough twist for accuracy with long, heavy bullets. You can't have your cake and eat it, too, demonstrated once again!

[LRRPF52]

I looked at both of these cartridges back in 2003-2004, and decided to wait and see how things developed before jumping the gun on one of them. They are both great cartridges, but the BC advantage of .264" pills wins in not only intermediate-to-long range, but in short range on cutting through tough hide on game, or penetrating barriers.

The external ballistics are such that trajectories of same barrel length, similar bullet weight and bullet type have academically different arcs out to about 250yds, from which the Grendel slowly starts to out-gas the 6.8 SPC.

The 140gr Berger VLD is meant for the .270 Winchester, and I have a box of them for my .270, which doesn't get shot that much anymore since I also have a .260 Remington. The .270 makes an awesome antelope or elk rifle, and retains energy beautifully out to 500yds, with a very flat trajectory compared to .308, but the .260 out-gases it with 250fps less muzzle velocity using the same bullet weights/types, like the 140gr Berger.

You need a tighter twist or high muzzle velocity to stabilize that bullet because of the bearing surface, and I mean in the 2900fps mv region from a 10" twist .270.

The 140gr Berger load would need a tight twist in the 6.8, but I don't need to play with 140gr pills in the Grendel if I want BC, as the 129gr Hornady SST or 130gr Bergers and Normas will provide plenty of BC, and decent mv.

The 140gr 6.8 would still be a great steel silhouette gun for out to maybe 500yds, if accuracy is there.

[Bill Alexander]

It is sort of funny but after all these years people are still trying to make the 6.8 into a Grendel. Now they have bullets too long for the mags and close to proof loads but they can almost do it. I suppose the competition is good for the products which is in turn good for the customers.

I understand Grimmy's position re his Grendel. Having looked at the same conundrum, I undertook to redraw the barrels as a whole. We still carry the heavy stuff as it does well for the dedicated long range guys but the more general shooters should look ate the Lite series barrels as well as fluting options. I have 16", 18" and 20" fluted set ups that weigh only fractions of an ounce over a pencil barrel. Still have the 16" CHF chrome lined M4 style which is brutal tough but not everyone wants the weight so we have fluted version using a Lite profile. Use a Grendel with a 16" or 18" barrel and you will find the versatility.

[tcte]

Bill what about grendel SBR's? Do you guys offer 10.5" barrels, not just complete uppers? Id like to hear what people have to say about 6.8 and Grendel out of the shorter barrels and if people think its worth making the switch from 6.5 to 6.8 on an SBR. Obviously its somewhat subjective to the end user's application. Why do people seem to favor the 6.8 so much when they're so close and most likely the grendel (SBR) should be able to shoot out a little further. There really isn't any data around for 6.5 10.5 barrels!

[woohoo]

SSA started loading the 140 Bergers only about a month ago. Personally I don't see much need or use in them but it may have something to do with LWRC making a lower with a longer magwell and Federal getting onboard to produce ammo for the foreign contract LWRC has.
Berger recommends an 11 twist for the 140.

[JASmith]

I was enamored of the SPC when it first came out. Then when I saw what the Grendel does, I have not looked back.

I continue to wonder at how folks can continue to maintain that the 6.8 is a superior mid-range cartridge. That apparent difference is due to the continuing illusion that a 140 gr 6.8 projectile is the same as a 140 gr 6.5 projectile. They are not.

The smaller diameter 140 gr bullet will trump the 6.8 bullet every time even though the larger diameter bullet starts out a little faster.

Part of the confusion results from the cartridges being so close in terms of case capacity. So the differences are not particularly obvious until one digs into the details. Hence, comparing a 16" barrel in one caliber with a 20" barrel in another overwhelms the slight differences in muzzle velocity.