Is it possible to use retumbo with the 240gr SMK in a RUM, or is it too fast burning? I am using us869 currently with good results. However my brothers rifle does not like the same combo. We have some retumbo and wanted to try another combo but can not find any info on the combo. Where to start? I can not find any H1000 or 50bmg locally or I would just try that. Any help is appreciated.