Gentlemen:
Thank you very much for your cudo's, I appreciate it.
Camp Cook said:
There is only one 6.8 SPC rifle in Canada that is worth having = non-restricted XCR-L it is now my go too deer/coyote hunting rifle...
Camp Cook & Ardent
I am glad we agree on Caliber, however I will Respectfully disagree with you on your choice of platform. However different strokes for different folks, and we all do our best to use the appropriate tool for the Job.
carbonrod said:
Not sure what you mean by power for a bullet, but if energy the 80% is rounding in the 6.8s favor no?
308 150 gr 2,820 ft/s 2,648 ft·lbf -- 24 inch, but a pretty soft hunting load for a 308 IMO.
6.8 115 gr 2,575 ft/s 1,694 ft·lbf -- 16 inch, but we are talking carbines.
6.8 115 gr 2,800 ft/s 2022.7 out of a 24 inch pipe.
Carbonrod:
Respectfully, I really do my best not to lend myself to exaggeration. Further, I'm not really sure where you are getting your data (as you haven't sited your data source), nore am I clear as to what your experience with both calibers is.
However having worked with both calibers in 16" AR carbine configuration, it has been my experience, that for the 16" carbine configuration, the 80% rule of thumb holds true, but allow me to qualify that statement.
You will never reach that 80% power thresh hold with factory loads. Factory loads are very mild, and are taking in to consideration that there are many Sami spec chambers out there with a 1-10 twist (ala RRA). It has been found that this barrel configuration, while reliable and hard hitting, causes increased pressure prematurely, or moves the pressure curve forward, and is not optimal for ballistic performance in an AR.
What has been found to work well is the SPC II chamber configuration, with a 1-11 twist. This elongates the pressure curve and allows excellent performance in the 90-115 grain range (with 110 grain bullets being optimal) with out battering the action components and allowing for very good carbine longevity. Those manufactures who are serious about this caliber have gone to that configuration.
I will grant you, there is no real replacement for 7.62 NATO, and it is really one of my favorite caliber in an AR configuration. Lets Face it, the 7.62 NATO has been turning cover into concealment long before the 6.8 SPC was a gleam in its creators eye.
However where space, weight, muscle memory, ammo payload, and penetration are chief considerations, it is very difficult to beat the 6.8 SPC in an AR package.
Again I am just a lay person, and there are just my thoughts. However if I could only have one black rifle, it would be in 6.8 SPC
Regards and all the best
AbH
