I have a 25 SAUM and worked with the designer of the bullet last year on testing it. I found RL26 provided best velocity. 61.0 gr of RL26 out of a 27” 7.5 twist Bartlein barrel was good for 3330-3340fps. Retumbo is too slow and not worth your time. H1000 and RL26 will get you in the upper 3200...