Ribs are no big deal at all providing you have able bow weight, heavy arrow weight and most importantly a tapered and smoothed transition between point and shaft. smaller points penetrate better for sure. After the last 5 deer and hogs i've killed with stone, Ive grown more particular in the workmanship in my arrows. but even shooting 60-65 pounds and decently heavy arrows, I have yet to penetrate a shoulder. bounced off the shoulder of 1 medium sized hog, 2 deer and 2 turkey shoulders. But i get awesome penetration now on my ribcage shots, always out both sides.