Build Thread 6.5 Grendel or 6.8 Rem SPC?

[CamoDeafie]

Got my C7 stripped upper, and the CMMG "premium lower parts kit" today, here's how they look so far on the NWFA Anderson lower (thanks again @HA556 !) ;
I will likely swap the tan trigger guard for the black one.
I'm still figuring out which barrel/BCG. I can get a Faxon 12" 6.5 Grendel barrel, or a Bison Armory 11.5" 6.8 SPC II; their BCGs and magazines are pretty much the same level (within few dollars if any)
For sure, pistol buffer and a cheek rest, no blade or brace at least until Magpul releases their versions. The look I am really going for... is basically a 1990s C7A1 Commando pistol, with carbine round handguard and triangle FSB.

Read More

 

[Swiss_Cheeze]

At this time I think I would look at availability of ammo and price

 

[Cavedweller]

I'd go with 6.5 Grendel. 6.8 SPC ammo is kind of spendy. The Russians are making 6.5 Grendel, so you can get cheap Wolf ammo for about $6.00 a box (when available) for practice and plinking. Plus, 6.5 will give you more range.

 

[v0lcom13sn0w]

grendel 100%

 

[Crazyeye24]

Ballistically, they're very similar out to 500 yards then the 6.5 has a slight advantage after that. I've built both and have settled on the 6.8SPC. I've taken 3 deer with it and am impressed with it's performance. I dropped mine with a 18" Bison Armory Recon barrel, extremely accurate....at least for me. Have never shot a faxon barrel so I can speak to that.

 

[titsonritz]

Personally I wouldn't do either on an A1 upper.

 

[CamoDeafie]

Its a Luth-AR reproduction upper with the Anchor Harvey mark. This as close as I can get without SBR'ing, what I want, only not in 5.56 or .300BLK. Basically a pistol version of the 733 upper. ​

 

[Twodogs]

I've got a 6.8 spc with an 11.3 " barrel and can get 2700 fps with a 90 gr bullet.
Have shot deer and coyotes with my 6.8 spc.

 

[andreys21]

I think Grendel is cheaper and more available. Love 6.8SPC tho.

 

[v0lcom13sn0w]

Personally I wouldn't do either on an A1 upper.

yeah i didnt take that into consideration! i agree.

 

[CamoDeafie]

Man , when's the last time anyone ever done a C7A1 upper SBR/pistol in an alternate caliber??? I mean... A3/A4 flat tops are everywhere in all kinds of calibers but it really seems for the C7A1, the standard is apparently either 5.56, or rifles.

 

[titsonritz]

A3/A4 flat tops are everywhere in all kinds of calibers but it really seems for the C7A1, the standard is apparently either 5.56, or rifles.

There's a reason for that, the flat tops work better at mounting optics which the 6.5 and 6.8 should have to make the most out of them. If the goal is a different caliber C7A1 than why not 300BO or maybe a big bore like 458 SOCOM or 450 BM? Seems like a conducive setup too me.

 

[CamoDeafie]

There's a reason for that, the flat tops work better at mounting optics which the 6.5 and 6.8 should have to make the most out of them. If the goal is a different caliber C7A1 than why not 300BO or maybe a big bore like 458 SOCOM or 450 BM? Seems like a conducive setup too me.

The problem with .300BO... there ain't a carbine gassed .300bo barrel with under 16"length. Ditto for the .458 and .450 for short barrels. All uses pistol gas for the heavy bullets and usually suppressor. But as far as I can tell, with a 11.5-12" barrel, optics don't really improve that much in comparative performance as the ammo isn't going that far? I mean.. the 5.56 would also benefit better with optics at 300+ meters right? with that said, I've been seeing a lot of info saying that both the 6.5 Grendel and 6.8 SPC outperforms the 5.56 out of 11.5-12" barrels; in terms of velocity and energy. With the older A1/A2 sight pictures, I feel more confident using irons than optics at the least.

Edit. If I'm gonna build a rifle, it will have a flat top because optics would make more sense for the longer ranges and higher velocities possible with 18"-20" barrels.

 

[v0lcom13sn0w]

whats wrong with a pistol gas system on a 300? mine runs just fine. 10" barrel with supers and subs suppressed and unsuppressed.

i would love a 12.5" 6.5 grendel with a 1-6x on it just to have one. ive heard the term "room clearing sniper rifle" before.

6.5 grendel really shines past 400 yards. i have an 18" grendel that i love shootin far.

 

[CamoDeafie]

whats wrong with a pistol gas system on a 300? mine runs just fine. 10" barrel with supers and subs suppressed and unsuppressed.

i would love a 12.5" 6.5 grendel with a 1-6x on it just to have one. ive heard the term "room clearing sniper rifle" before.

6.5 grendel really shines past 400 yards. i have an 18" grendel that i love shootin far.

Because I want a triangle front sight It would look beyond ridiculous having a triangle front sight 4 inches away from the carry handle, and another 4 or so inches of barrel sticking out (assuming 3 inches of sight)

 

[v0lcom13sn0w]

Because I want a triangle front sight It would look beyond ridiculous having a triangle front sight 4 inches away from the carry handle, and another 4 or so inches of barrel sticking out (assuming 3 inches of sight)

gotcha!

 

[CamoDeafie]

That said, I dont know of any currently available picatinny mounted front sight thats in plane with the A1/A2 fixed carry handle?

 

[v0lcom13sn0w]

ive seen clamp on a2 front sights.

https://shop.deztacticalarms.com/A2-Fixed-Front-Sight-Clamp-on-750-w-Bayonet-Lug-DEZ-1035-GB.htm

 

[titsonritz]

ive seen clamp on a2 front sights.

https://shop.deztacticalarms.com/A2-Fixed-Front-Sight-Clamp-on-750-w-Bayonet-Lug-DEZ-1035-GB.htm

I don't trust clamp-on FSBs, especially if you plan to drape a bayonet on it, your creating a shut-off valve.

 

[CamoDeafie]

ive seen clamp on a2 front sights.

https://shop.deztacticalarms.com/A2-Fixed-Front-Sight-Clamp-on-750-w-Bayonet-Lug-DEZ-1035-GB.htm

I don't trust clamp-on FSBs, especially if you plan to drape a bayonet on it, your creating a shut-off valve.

I don't mean like a clamp on gas block front sight, I mean like a front sight for say, a free float tube that's at the same height as the A1/A2 fixed sight. Seems I remember that there are two different FSB heights due to the flat top rail and the original carry handle setups having a different plane so to speak