Which round for big game AR-15?

[hk_shootr]

6.8 gets my vote

[pinzgauer]

I was talking about 6.5 specifically vs 6.8 range.

My point is that 6.5 fans will always bring up drop and I don't think it has any place in hunting discussions. It's just not relavent at the range we are bullet performance limited to.

Fair enough, though the (much) higher BC's have a big impact on wind drift, etc in addition to drop & retained energy.

I guess it depends on your AO and idea of reasonable range. For me, it's 0-300 yards, well within Grendel performance with the bullets I use (mostly SST). So I look at +- trajectory. Really want something I can do dead on holds, or a very simple holdover. At that range, most 6.8 I've seen has 2-4" additional drop compared to Grendel, sometimes more depending on projectile.

TTSX loadings I'd pull a bit shorter, but still good to 200-250 yds. But also due to lighter bullet.

Likewise, it's very hard to find side by side tests, same protocol, similar bullet weight, etc on factory Grendel/6.8. Hornady does publish very similar loadings on very similar bullets (SST 123 vs 120g). You'd think SPC has the edge there, but it does not. Which will trigger "you need to use the hotter doubletap/SSA" or similar discussions. Yep, find comparative ballistics on them. Would love to see some recent, objective tests. (Truly interested...)

What I'm able to find, Doubletap 6.8 loadings are virtually identical to comparable grendel loadings for the same barrel length. (yep, even 16"). So were the limited SSA loading ballistics I've been able to find.

There may truly be a magic 6.8 loading out there. I'd love to know about it. What I do know is the hunting loadings (grendel & 6.8) that I see commonly available in stores are Hornady SST, with an occasional lame RP FMJ/HP loading for 6.8.

I'd take either for hunting, though over blackout or 7.62x39. And I like 7.62x39, just not for hunting.

[pinzgauer]

One last thing, some of the declarative comments on 6.8 are from an individual who sells 6.8 Barrels with non-std chambers, yet does not self identify as a vendor here. From his store website:

"NOT 1 company loads factory 6.8 SPCII ammo. Since none of the companies will load factory ammo to the higher velocity I have done what I could to increase the velocity with the barrel and chamber design. The 5R and 3R 6.8 barrels sold here normally produce 60-100fps more than the common 11 twist 4 groove barrels when the same factory ammo is used in both types of barrels."

That's a very interesting statement. Also good to know it might improve factory performance some. But telling as well.

Also has quite a bit of experience with many wildcats, etc. Just be aware that some have a very strong vested interest in pushing 6.8... hard.

Me, I'm just a satisfied Grendel hunter/user for right at a decade, not associated with any vendor. (Though I did talk to Bill Alexander some once last spring). If SPC had any tangible advantages I'd cut over if I could validate.

And I'll admit, one of the reasons that swung me to Grendel early on was that I was able to fireform grendel brass from 7.62x39 when neither Grendel or SPC was available anywhere. Still using some of those cases. (Was decent brass, IMI made by Lapua)

[Lefty223]

My point is that 6.5 fans will always bring up drop and I don't think it has any place in hunting discussions. It's just not relavent at the range we are bullet performance limited to.

^ ^ ^ T H I S ^ ^ ^

[C. Stevens]

Velocity vs Barrel Length was a deciding factor for me in choosing 6.8x43 over 6.5G.

I get >2,500 fps from a 12.5" ARP barrel, and >2,700 fps from a 16" ARP using 6.8spc 110 grain projectiles.

The numbers I've seen for 6.5g just seemed either slow, or were from 20"-24" barrels.

Since I don't often shoot past 300 ( and wouldn't think of shooting game at those ranges), the 6.8 made more sense for me.

But hey, each to their own.

"Here's the closet ballistic comparison i could find. Notice that when both rifles fire from a 16in barrel and use a 120gr ballistic tip bullet the lower range advantage of the 6.8SPC completely disappears. The Grendel takes over right away and keeps the lead to 1000 yards. Also notice the Hornady HITS scores. 500+ is considered adequate for medium game. 499 and under is varmint shooting. The Grendel has better HITS scores which means better killing power right from the muzzle. With these bullet combos 6.8SPC is a 300 yard deer gun and the Grendel is a 450 yard deer gun." Msrhunt

Not my data, quoting a Grendel enthusiast... Thought it was relevant to the 16" barrel ideas


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[C. Stevens]

"Here's the closet ballistic comparison i could find. Notice that when both rifles fire from a 16in barrel and use a 120gr ballistic tip bullet the lower range advantage of the 6.8SPC completely disappears. The Grendel takes over right away and keeps the lead to 1000 yards. Also notice the Hornady HITS scores. 500+ is considered adequate for medium game. 499 and under is varmint shooting. The Grendel has better HITS scores which means better killing power right from the muzzle. With these bullet combos 6.8SPC is a 300 yard deer gun and the Grendel is a 450 yard deer gun." Msrhunt

Not my data, quoting a Grendel enthusiast... Thought it was relevant to the 16" barrel ideas


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"Look a this side by line up. The 123gr SST in the Grendel VS the 120gr SST in the 6.8SPC." msrhunt



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[MisterHelix]

Thanks for the data comparison. To me, regarding realistic and common big game (deer) hunting ranges, it looks like it doesn't matter a whit which of the two you choose. Really splitting hairs, I think.

I'd only shoot whitetail within the MPBR of a given cartridge, and it looks to me like both rounds top out somewhere just over 200 yards, perhaps a bit more if the data wasn't based on a 100 yard zero. Given the data listed above, as it relates to estimated bullet performance thresholds, sure, 6.5g will expand/fragment for an addition 50yards or so. I think it's academic though. I'm not going to dial in 20" of dope when hunting deer.

Maybe I'd think differently if I lived out west instead of in the hills of Virginia.

Either way, it's a big *shrug*. Same difference at typical hunting ranges.

(Though I do prefer the 110-110 grain class of projectiles starting at ~2,700fps myself)

If I were hunting elk or bear or whatever, and/or shooting past 250 yards, I'd be looking at cartridges in the .308/6.5c class anyway. But I'm a pretty conservative hunter.

[C. Stevens]

Thanks for the data comparison. To me, regarding realistic and common big game (deer) hunting ranges, it looks like it doesn't matter a whit which of the two you choose. Really splitting hairs, I think.

I'd only shoot whitetail within the MPBR of a given cartridge, and it looks to me like both rounds top out somewhere just over 200 yards, perhaps a bit more if the data wasn't based on a 100 yard zero. Given the data listed above, as it relates to estimated bullet performance thresholds, sure, 6.5g will expand/fragment for an addition 50yards or so. I think it's academic though. I'm not going to dial in 20" of dope when hunting deer.

Maybe I'd think differently if I lived out west instead of in the hills of Virginia.

Either way, it's a big *shrug*. Same difference at typical hunting ranges.

(Though I do prefer the 110-110 grain class of projectiles starting at ~2,700fps myself)

If I were hunting elk or bear or whatever, and/or shooting past 250 yards, I'd be looking at cartridges in the .308/6.5c class anyway. But I'm a pretty conservative hunter.

No worries. I think you're right. I said it before, game you'd hunt with both won't know the difference within the typical range of the average hunter. About 300yds max.

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[TMS951]

I am building a 458 SOCOM upper for Bear and Moose. Here in dense mountainous north eastern forrest I won't be taking any long shots. Likely 50yards and in.

[Goldorak]

Looking in the newest Natchez catalog, I find:

6.8 SPC

-Federal Fusion MSR 115gr $20.69
-Hornady
BTHP 110gr $42.99/50
V-Max 110gr $19.69
SST 120gr $20.89
-PPU
FMJ BT 115gr $13.79
HP BT 115gr $13.99
-S&B PTS(?) 110gr $18.99

6.5 Grendel

-Hornady
ELD-X 123gr $19.69
ELD Match 123gr 19.69
...and that's it.

I haven't checked Cabelas and your local stores, but, for what you do, ammo availability would be the deciding factor.