What's your impression of/take on the 6.8?

[oldtexan]

Has anyone been able to reach any conclusions on durability (in terms of round count) of a 6.8mm AR versus a comparable quality 5.56mm?

And what trends are folks seeing in parts failures with the 6.8mm? What parts fail and when?

[JPB]

Thanks for all the suggestions. I understand the chamber reaming route, and probably would have considered that had this been a SS barrel. This was a CL chamber/bore barrel, and call me crazy, I just wasn't comfortably reaming out the chrome as I really wanted it there! Also, I wasn't sure how the resulting chrome/steel interface would wear in the long run. I was afraid the resulting steel/chrome interface may serve as a compromised nucleation point for chrome to begin peeling.

Being concerned about CL, I would be curious to see if the Vietnam era malfunctions that resulted from corrosion in the chamber (that the chrome was introduced to mitigate) persists with the larger caliber ARs (6.8, 6.5, 7.62). How well can the SS barrels hold up in this regard? SS can corrode as well. Different topic for a different thread, but I believe that Armalite is the only 7.62 AR manufacturer that offers a CL bore. It may be that these old extraction problems that necessitated CLing do not persist accross the larger caliber spectrum, or maybe nobody cares.

It'd be an interesting study......

[Stephen_H]

Has anyone been able to reach any conclusions on durability (in terms of round count) of a 6.8mm AR versus a comparable quality 5.56mm?

And what trends are folks seeing in parts failures with the 6.8mm? What parts fail and when?

I have owned maybe 8 different 6.8mm rifles over the last 5 years (built my first in September 2004 with a Model 1 Sales kit when it was either that or a custom rifle). I still have 4 that were weaned out as my favorites of that bunch. I have fired 10,000+ rounds of factory loaded ammo (mostly SSA, but some Rem and Hornady) and another 3,000+ hand loads. I have run several of these guns through 2 and 3 day carbine classes.

I say all that as a qualifier to my opinion; I have not seen a difference in reliability or durability between a 6.8mm carbine and a comparably built 5.56mm gun.

Stephen

[carbinero]

Now that is good to know.

If you still have a concern, http://ar15performance.com/parts offers a super duty bolt for both 6.8 and 5.56.

[BLACK LION]

I have owned maybe 8 different 6.8mm rifles over the last 5 years (built my first in September 2004 with a Model 1 Sales kit when it was either that or a custom rifle). I still have 4 that were weaned out as my favorites of that bunch. I have fired 10,000+ rounds of factory loaded ammo (mostly SSA, but some Rem and Hornady) and another 3,000+ hand loads. I have run several of these guns through 2 and 3 day carbine classes.

I say all that as a qualifier to my opinion; I have not seen a difference in reliability or durability between a 6.8mm carbine and a comparably built 5.56mm gun.

Stephen

Definately good to know Stephen... Thanks!

[LastRites]

Seems like the original poster has gotten himself a new upper of choice!

[rob_s]

Seems like the original poster has gotten himself a new upper of choice!

and if I'm lucky it will be assembled into a complete gun today.

FWIW, that upper was on order already when I posted this thread. I had to wait first for the new spec barrels, and then for the new SB rail.

[RetreatHell]

and if I'm lucky it will be assembled into a complete gun today.

FWIW, that upper was on order already when I posted this thread. I had to wait first for the new spec barrels, and then for the new SB rail.

I'm sure you already plan on doing it, brother, but please do inform us on how your new 6.8 upper runs and your overall opinion of it after you fire enough ammo out of it. I'm very interested to hear your findings, as you're always a very objective reviewer regardless of how you acquired something.

Have fun shooting the new blaster too!

-Paul