There is a support upright for the cartridge follower compressor tab. There are also thin connections from the support and compressor tab to the speed loader frame.
Cut the thin connections to the frame and break the upright support free. The support piece will break about 18 mm (almost 3/4") down from the top of the loader. Run an exacto or thin blade between the frame and the follower compressor tab (the protrusion). If needed, clear between the tab and the frame to nearly 25mm from the roof of the inside top of the loader.
You may not need more trimming depending on your printer.
Magazine clearance behind tab.