6.8 SPC notes/observations

[DJL2]

I realize the 6.8 SPC is the choice of exactly 0% of long range shooters, but figured I would share some observations and ask a couple questions.

- 6.8 SPC is the most consistent factory loaded caliber I’ve sent over the MSv3 so far**
- 6.8 SPC has produced the lowest SD of anything I’ve loaded so far (between 4 and 12, depending on “batch” and charge)
- two notable exceptions to the above: REM UMC - known to be garbage, it lived up its billing; Nosler/SSA - also consistently evidences an ES of about 100, I can shrink the SD to around 35 or so with a large sample and some luck...but, overall garbage tier.

Questions:
How much does case volume/shape influence ease with which low MV SD can be attained? How much better is a BR/PPC (Grendel/ARC?) case in performance, if at all? Is it simply the ease with which said performance is achieved that makes them popular? Is the Valk similarly consistent?

How much temp sensitivity is typical for factory loads? I’ve seen very consistent velocity session to session, but I saw enough of a difference today that it has me wondering about the health of my MSv3.

Is Nosler/SSA usually garbage or am I just shooting my way through a bad lot?

**That includes .223 REM, 6.5 G, 6.5 CM, 7mm RM, .30-06 that I’ve kept/can find my data on. Hornady SD has run around 9 fps for both the 110 BTHP and 120 SST. PPU SD has been between 11 and 12 fps for their 115 BTHP. S&B SD has been right about 14 fps for both their 110 PTS and FMJ loads. By comparison, my Barnes VOR-TX 7mm RM SD was 16.2 fps (and decidedly more consistent than any other tested ammo in my T3x). Lapua match ammo out of my AR ran around 18 fps for SD. Those are the stand outs. It’s not uncommon for factory stuff to chrono on my MSv3 at between 20-30 fps SD.

 

[Powder_Burns]

SSA was tits before nosler bought them out.

 

[DJL2]

SSA was tits before nosler bought them out.

Thank God...I thought I was losing my mind...

 

[346ci]

Art helped pave the way for 6.8 when he ran SSA, other than some recalled high pressure tac loads, their ammo was the standard choice for most shooters. As mentioned, once bought out, went down hill.

I have shot and still use some old Hornady 120gr SST for deer. They had some bad batches also, can't recall now but there were some lot numbers or dates you could go by for the 110gr vmax. I didn't chrono many of these though vs. hand loads.

As for long range, a hand loaded 140gr Berger does well but the COAL is too long for standard mags. Cavity back bullets did offer a PRI mag with the front machined out for those longer rounds.

 

[Powder_Burns]

The 6.8 was designed as an intermediate range cartridge, think 7.62x39. Making it a long range choice is wishful thinking at best. With offensively hot 85gr tsx handloads I got 3300fps and wrecked brass, offensively hot 130gr speer bthp got 2550fps and wrecked brass. My oal for the speers were 2.295”, only the pri and barrett mags would fit those. SSA brass was the go-to early on with small rifle primer pockets and a thicker case versus the remington with large rifle primer pockets, but as of late I’ve seen a lot of variance in case capacity with ssa/nosler.
I never got around to trying the 120gr sst or the berger 140’s, but there just isn’t enough case capacity to push those rounds much faster than 2400fps, its not going to do better than a 5.56 in the trajectory department. If someone made a 77gr .277 dia bullet, I think it could outperform the 5.56 at distance. I suppose this is why the .224 valkyrie is a thing. The 6.8 has found a niche with deer harvesting inside 300 yards.

 

[DJL2]

Concur. The 6.8 is serviceable to 6-700 yds as a target cartridge or 300 yards on appropriately sized game in my opinion, from my rifle.

That’s OK for me most of the time - damn hard to find game the 6.8 won’t kill where I live, or a shot longer than 100 yds. Likewise, a range with targets further than 400 yards is going to require either a trip to my folks or a membership at the Arena.

I would guess the Valk pushing 80-88 grain bullets is superior as a target gun... while being inferior to the 6ARC. That being said, the .223 77 grain SMK CorBon I have chrono’d at 2530 FPS from my 16” AR. Between my two 16” AR, the 6.8 wins. Honestly, that’s so slow I wonder if I mixed my notes up and that’s from my SBR...

 

[Zback]

I use a Wilson Combat AR 15 chambered in 6.8spc for my exclusive thermal rifle for hogs and predators and love it. You can see some of my videos/pictures on here. I shoot the Hornady 120gr sst. As you mentioned, at times I wish I had something flatter.