When you consider that NRA 50/50 is half Alox and that millions of military rifles were well preserved using Alox, I have to think a thin coating of Alox deposited in the barrel by a cast boolit would serve quite well.
I have noticed that the first boolit fired from a freshly cleaned barrel usually does not go into the group with the rest. Normally, this only happens on the first shot. When not having cleaned the barrel between range trips, that first round is in the same group with the rest.
I have never found any rust in the barrel between range trips when using cast and lubed boolits.