Let me share some of my experience with them. I shot a deer with a 190 grizzly El Grande. The arrow did not pass all the way through somehow, probably because of the shot angle. It was sticking out the other side. The blood was pretty good the whole way. I am shooting 780Gr CX 350's and out of my setups listed below, so I know I had more then enough mustard to get the job done.
I shot another deer this year with a 190 Grizzly El Grande, and this time the arrow went right through it and was buried in the ground. He went 15 yards, and never even knew he was hit. I got down after watching him lay down and expire, and noticed there was barely any blood if any. I send all of my Grizzly's to Ron @ KME, so I know they are scary sharp.
A couple of weeks ago I had shot a Turkey with a 160 snuffer and had somehow lost it. It flew and I never recovered it.I looked for hours. I'm not bashing Snuffers as I still believe in their lethality. I got these heads especially for Turkeys, I just don't know what had happened and have a cut wing feather for my efforts.
A few days later, I had shot a Jake and it went a total of 25 or so yards after the shot. I had shot this one with another Grizzly. But I noticed there was not a lot of blood with this one as well. I have read a lot of things that go both ways, if 100 people say the blood trails are minimal, there is another 100 people say they have awesome blood trails.
So I'm not to sure what to think. I am convinced that the Grizzlys are great heads and do preform well though.