Hi Dave,
hope you`re doing well.
I have contacted Huub from HuMa. De filling valve of the Kral`s are pretty large in diameter, som 1/2" and since we`re shooting with an external regulator a smaller filling valve would be better. The smaller the diameter the easier it opens. With an HuMa regulator the gun will work with a much more stablie pressure and it`ll shoot better groups. I have to find a way to make the valve open easier. If this will work for the .22 Pallas it`ll do the job for the .25 Kral Puncher Pro too i suppose.
Best regards, Roel