I used to use them back in the 70's with a 45lb bow with the bleederblades. Best I remember I never had a problem with penetration and had good bloodtrails. The only reason I stopped using the bleederblades was because they sometimes broke off if ya hit bone. Just like Mr. Bear designed them too! Thats what I got on the end of my arrows this year. I'm a thinking Mr. Bear might have the "solution" for the problem of "penetration vs bloodtrails" A 4 blade for a nice bloodtrail unless something heavier than a rib was hit and BINGO!, the thin bleederblade breaks off and now you have a 2 blade for penetration. Only problem is that them ole' green Bear broadheads bring a nice price. Not to worry, the Magnus 125 vented can use the Bear bleederblades too. Might need to secure it in place with a dab of glue. Sorry to be so long winded but just my 2 cents worth.