ok guys over the summer i want to try some thor's in 300gr. but what i need to know short of makin a slug of my barrel (i dont know what its called when you make a cast of your bore) how can i determin what sive to order? in my gun ap pursuist lt a 300gr. .452 45 cal xtp with a harvester crush rib is snug and shoots perfect, non crush ribs are real snug and a fbp was way to tight. so how nad i determin what size to order? or should i buy one of the slug things and make a exact size of bore slug and measure from there? also was told like i said told i did not see it that the fbp came out they were tight in most guns but are ok now? anyone else have a idea on this? and also what about barns? its that its just gettin pricey for me to keep buyin stuff so i figure if i can eliminate say sabots i can over time get ahead maybe. cause i just cant bring myself to go back to a center fire rifle after using a muzzle loader!! i will keep my shotgun for quick thick places and drives but other than that my center fire days are done.