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6.8SPC = .270WIN?

11498 Views 11 Replies 6 Participants Last post by  msredneck
was talking to a friend and he was asking if the 6.8SPC is the same as the .270 Winchester...

anyone know? the paper shows it as a .270 caliber, but is that just the size of the bullet, or does that mean he can buy .270 ammo and shoot it through this AR?

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Caleb C said:
6.8mm is roughly equal to 0.27 inches (0.2677 to be exact). This means that the bullet is the same diameter. Reloaders could use the same bullets for loading 270 Win and 6.8 SPC. Like Beladran was saying, the cases are not even remotely the same. It would be interesting to compare velocities and trajectories of bullets of equal weight fired from both 270 Win and 6.8 SPC. Anyone have experience with these two rounds?
Yes. The practical upper end of the 6.8 is the 130 grain bullets. Within 100 yards, the 130's are a good choice on medium game, and even hogs. But the 6.8 is really better suited to bullets 85-115 grains. The best BC bullets are around 110 grains, and they carry the most energy downrange (beyond about 200 yards). The Nosler Accubond 110 grain is a real champ is you're gonna be shooting your 6.8 at those longer distances.

There's a really huge chart full of load data for 6.8 here. Be aware that since that chart came out, several new bullets have come out that are designed specifically for the 6.8. Namely the Barnes 95-grain TTSX, and the Nosler 100-grain accubond.

As one other person mentioned, there is the original chamber spec, and the new one. (There are actually more than that, but the others were produced in limited numbers and aren't in production any more.) The difference in performance between the original SAAMI spec and the newer non-SAAMI spec (commonly known as 6.8x43 or 6.8 SPC-II) is really quite significant. The new chamber has a longer leade before the bullet contacts the rifling, and this reduces pressure, which allows you to load hotter rounds. So when you look at that chart linked above, be sure to note what chamber the load is for. Hot loads that are safe in new chambers routinely blow primers (or worse) in SAAMI spec chambers.

As far as 6.8 vs 6.5 Grendel, well I don't want to get too deep into that fight, er discussion, because they're both great. They just have different strengths and weaknesses. In terms of ballistic performance, take a look at this chart which shows Grendel vs 6.8 SPC energy and bullet drop at 300 yards for some of the popular bullets. IMHO, they're neck and neck out to 300 yards. Since I'm not gonna shoot game past that, I like the bigger caliber and bullet selection better in 6.8. If I was punching holes in paper at 400+ and that was all I wanted the gun to do, I'd probably own the 6.5. But I like a shorter gun, and the 6.8 with a 16 or 18" barrel will equal the Grendel that has a 20+ barrel. You can get more ammo in the magazine with 6.8 because it's smaller. 6.8 ammo weighs less so you can carry more of it on you. It takes less powder to load 6.8. The bullets and brass are less expensive too. Just my opinion though. HTH.
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