6.8 SPC Help
I bought a 16 inch 6.8 upper from JT Distributing about 10 years ago. It had the original Spec I chamber and 10 twist rifling. I worked up a load using 110 Sierra Prohunters and 28 gr of 322 which was very satisfactory, around 1 MOA, with a velocity of 2400 fps.
Thinking that a longer barrel, new Spec II chamber, and 1:11 rifling would be a lot better, I recently bought a Stag upper of 18 inches with no flash suppressor.
Here is my problem; my old, tried and true load throws slugs all over the place out of the new barrel. It is lucky to put them on a paper plate. So much for one load for 2 rifles.
I have since worked up a 115 Sierra load that is around an inch at 100 and another with 110 Hornady’s which is also around an inch. The Hornady’s are clocking 2700 fps with the Sierras around 2630 with H-322. Still, these two loads print about a foot apart from each other on a diagonal.
I have never experienced anything like this before and wanted to know if any of you have experience anything like this or have any suggestions or comments. This works for me, but is not what I was trying to achieve.