Interesting video of a guy doing a home-grown penetration test with his Ruger 10/22.
http://www.youtube.com/watch?v=xAkOz...eature=related
What impressed me was of his accuracy at that distance. 300 yds is a real stretch for a 26 gr slug. The penetration was also not exactly what I was expecting. It does not make the 22 LR a sniper round. It took 7 or 8 shots to hit the roast, but it is a data point for you 18B's..