TruOil is not waterproof.
Perhaps but in my book, it is "Weather-Proof"...
I have taken my refinished stocks out, under terrible weather conditions and for many years. They are still going strong.
I have never heard of True oil ever failing anyone.
Besides the barrel channel, one area that is often neglected and lacking protection, is the wood under the buttplate. I too recommend a good application of carnuba wax.
Be Safe !!!