I’ve always liked the way a gunshot wound looks on film. Many people have switched to digital blood splatters because it’s easier and cleaner, but I think nothing looks quite as good as it’s practical and messier counterpart. The following video is what I used for the effects in Harry Potter and The Muggle Wand. It’s a very simple technique and doesn’t require any sort of explosives to project the blood.
Learn to make fake blood!