Learned something about chambering for slugs today

If you fully engage the slug in the rifling, its quite the velocity gain. However, its very hard on the cocking lever, and it wasnt very accurate. With the same tune 65.5 gr nsa slugs were hitting 1000fps fully engaged, slight engagement 905fps. Its pretty obvious why, just thought it was intresting.

That's gotta be wasted air, probably blowing past the slug instead if driving it. Which chamber throat reamer are you using (and how many degrees is the leade in cut to)?
 
What type of ammo are you testing with? I've been using a live piloted reamer that Dave Kiff from PTG made for me with great results. 1.5 degrees, .300 groove with .2925-.2965 bore pilots. Mostly with TJ barrels, I have had at least one lemon out of the dozen barrels, and many have had varying bore diameters (as small as .2925).