Huben Huben GK1 .177 most accurate pellets?

I'm wondering what the best pellets to try in this gun are for target accuracy at 30 yards or less, not terminal ballistics on critters? Highest velocity doesn't matter, but I would like it to be decent so that I have less problems with drop compensation. Best diameter, brand, weight? One type Hatsan Vortex pellets are sometime very loose, one move forward enough to jam the cylinder. I had to push it back into the cylinder with the CF rod.
 
I have this issue with a .25 caliber with one particular pointed pellet. Any pointed tipped pellet will do this because it doesn't come in contact with the magazine's narrowed rifling before the tip extends beyond the front of the magazine. Maybe it would be optimal to find a brand of pellet that is a bit heavier, so it is longer and has a wider skirt. That way it holds back onto the magazine instead of riding it forward.