Difference between 6.8SPC & 6.8SPC II?

[Abraxas]

What is the difference between 6.8SPC & 6.8SPC II? I have a 6.8 that I bought back when the round first came out that has worked fine, and up until I read a few things here I did not know that there was a mkII version out. What are the differences and what were the issues that lead to making those changes? To those who take the time to answer thank you.

[Abraxas]

Anybody?

[mark5pt56]

To my knowledge, there's been some chamber dimension changes. I don't know much else on it. There's a 6.8 forum that may have some more info.

[loonybin]

What is the difference between 6.8SPC & 6.8SPC II? I have a 6.8 that I bought back when the round first came out that has worked fine, and up until I read a few things here I did not know that there was a mkII version out. What are the differences and what were the issues that lead to making those changes? To those who take the time to answer thank you.
In a nutshell:

Remington screwed the pooch when they submitted the 6.8SPC chamber specs to SAAMI. Shooting hotter loads in a SAAMI chamber can cause pressure issues due to the leade being too short.
SAAMI correctly identifies 4-groove rifling as the standard. Most manufacturers use 6-groove -- increase in pressure.
Twist rate matters. 1:10 is too fast for hotter loads. 1:11 or 1:12 is generally preferred to get the most performance out of the 6.8SPC


These factors combined cause pressure issues which has led to most ammo manufacturers having to load down their 6.8 rounds. Silver State Armory offers a "Combat Load" for those who have the right kind of rifle, but you have to call them and talk to Art about your rifle's specs before he'll sell it to you. He doesn't want you blowing up your rifle with ammo that it can't handle.

If you go to 68forums.com (http://68forums.com), you will find a wealth of info that will answer your questions and help you get the most performance out of your 6.8SPC.

[Abraxas]

Great, thanks. :D