Just had a full rebuild done by negative airsoft.
I now wouldn’t use anyone else.
I have rebuilt my own rifs for years as had 2 “techs” from shops work on them (ruin them) when I first started the rabbit hole of airsoft.
I simply can’t be bothered to do it anymore and frankly having seen and now used his work I wouldn’t recommend anyone else.
A decent air seal, correct air volume and a maple leaf hop rubber with nub means it now throws bbs at 1 joule as far as any of my r/s hop patch rifs ever has.