pistols are too compact to add weights but i'm sure there are some spaces that will let you add a few grams here and there weight won't improve much max maybe 50-100 grams but a far easier method is get a deagle (a full metal deagle with a RDS is just sick and will get you to clsoe to 2kg), beretta, hi-capa, p226 or any gun that supports full metal frames and slides will get you the most weight (over 1kg). or you can get basically any GBB preferably HW frame slap a metal slide on and add weight by accessories, Tac light, extended mags, silencer, rds, etc. oh and use some heavy ammo lol
is this heavy enough?
not heavy enough for you? try adding a tac light on one side of the RIS and a mini gernade launcher on the other lol