.204 Serria bullets to soft for coyote

[Catfish]

I hit 3 and I think 4 coyotes today with the 32 gn. Serria bullets. I hit one hrad twice, knocked him dowm hard both time and he still got away. I came home and called Serria and they told me that the 39 gn. bullets were probibly to thin skinned also. With the accuracy I get with them I hate to give them up for coyote, but I`m going to have to find a different bullet. Does anyone have a .204 bullet that is upto the task???? or will I have to get my .17 Rem. out again?