I've been shooting 3-blade original Spitfires (100 gr) starting in 2017. Great flight, sharp blades, accuracy, quiet in the quiver and in flight, and most importantly they are durable. So far I have had pass throughs on a Tule elk, two Coues bucks, a couple nice black bears, a lynx and a Stone ram. On a large polar bear I got 29" of penetration into the far shoulder and a dead bear in less than 8 seconds. All blades survived just fine....I re-sharpen them on my Chef's Choice 120 electric diamond wheel kitchen sharpener. I haven't bent a ferrule on the heads either.