I have an airgun that got a really heavy double action trigger (jericho 941), tried silicone, gigaloo, oil.. nothing helped.... until I used the Prolab PL-100,
amazing lubricant, penetrate and stay on metal, do not harm plastic. now trigger pull is smooth, 1/2 the force needed to pull it now.
the only problem is the price, 25$ for a can! but works great!!!