Ive been thinking of building the longest length barrel possible 6.5 grendel pistol what is that 12.5. I think. I would also run a can on it. Do they have to be pinned. How is the performance of smaller 6.5 bullets in the pistols. And considering the can adding 6 inches on. (I know some say it can increase or decrease fps) dont want to open that can of worms. I would like to run the 90-100 grainers. What kind of range and performance could I expect. Thanks to all