I note Lone Wolf sells an adaptor to permit use of the Gen 3 recoil spring in a Gen 4. I will probably purchase a G19 Gen 4 in six months or so as the grip does feel better and I want to give it a try. I realize glock will probably get a dual recoil spring that works ok with a wide range of loads, but the LW adaptor and Gen 3 recoil spring does seem to have merit. I was thinking of using the Gen 3 recoil spring adaptor with all standard velocity ammo and save the Gen 4 dual recoil spring for +P carry loads. I would guess with +P loads is where the advantages of the dual spring really shines in reducing recoil, slide battering and excessive slide velocity. And the adaptor looks very stable and I would not anticipate anything slipping or jamming and appears it is easy to change out. So to me it would be worth the effort, if it permitted use low powered loads without concern. And a stainless steel adaptor against black finish would let you instantly know which spring was installed. Since the Gen 3 has a record of long service life I really don't see how use of the Gen 3 recoil spring in a Gen 4 could result in harm or excessive wear. The Gen 3 and Gen 4 do not appear to be all that different. Your opinion on this approach appreciated.