The electro-pneumatic leaked after one tank replacement. The Mauser and MP7 took a few reloads. Now to be fair I never replaced a tank before storing, but I treated my Crossman's and Dan Wesson's the same way and they never gave me issues. The Umarex replicas are more appropriate as collectibles or movie props in my opinion, because the full metal replicas look and feel like the real thing, but it won't go to hell and back like a Daisy or Crossman will.Thank you. How long before they leaked?