You could do worse than speak to Peter Jackson of Jackson's Rifles- he's a big importer with all the various Tech Spec sheets; I've just recently had a .30 ATEC Maxim (370grams) from him on the basis that, although fractionally heavier than the CMM4 (from memory ~40g), the mixed s/steel and aluminium baffles are longer lasting than the aluminium baffles in the CMM4 (~£13 ea to replace).
Also maybe the ASE UTRA? "..the S5 has been replaced by the lighter SL5, ... Ase Utra have redesigned the original S5 to be shorter and lighter but retain the same sound reducing abilities. The SL5 weighs 410 g against the 590 g of the S5. I have attached data sheets for both the S5 and the SL5, as well as for the A-Tec Maxim."