The runners were full 6"x6" poplar beams and still rather heavy. I figured that I'd cut them up into stove lengths and let them finish drying out before I use them as firewood this coming winter.
I knew that they had a few extra screws still remaining in them where my cross-members had existed, but of course, the saw suddenly stopped cutting dramatically on the final, mostly unneeded cut.
Yes, I found a screw that appeared to have broken off deep in the runner. This may be a good excuse to try out my new chain.
I have convinced myself that this is the sort of thing that happens to anyone who uses a chainsaw on a regular basis.