Wouldn't it be better if both ends of the roller were supported?
That gizmo is perfect for rested shooting by seniors:https://www.issf-sports.org/getfile.aspx?mod=docf&pane=1&inst=290&file=2017_ISSF_Rules_-_Supported_Rest_Shooting_-_Edition.pdf#:~:text=Supported%20Rest%20Shooting%20is%20an%20ISSF%20Sport%20for,the%20rifle%20or%20pistol%20on%20a%20support%20stand.