I bought some Phat Head 100's as per suggested, but they don't hit where my field-points hit... even though I paper tuned the bow. They are off about 1.5-inches (at 10-oclock) at 20 yards. That's a huge error given that I'm planning to go out to 50 yards, at-least. I use Rocket Steelhead XL 100gr broadheads with my vertical bow and so I wired some shut, added healthly amounts of superglue for good measure, and tried them at with the Tac15. Results have been mixed. At the archery range I was getting fine groups out to 80 yards and even 8-ringed the elk at 125 yards with these home-made practice-heads. Later, at home, the practice head groups opened up to about 2-inches at 30 yards, and given that I'm used to 1-hole groups at that range with field-points, it gives me pause. Last year I shot three of the Steelhead XL's through deer, and on one occasion had a blade come off in a deer. All deer died in seconds, so I can't really complain too much. But.... I'm wondering if 400 fps is a little fast for the Steelhead XL? Anyone know what they are rated to? I use 2 O-rings to keep the blades shut, so-far-so-good, the hits on deer have all been right where I expected. Would anyone else share their Tac15 broadhead experiences?