Water hammer in new float valve despite 'bucket'

Have just replaced a corroded float valve, in my cold water tank, with a Brass Float Valve High Pressure PT1 from Plumbworld.

Violent water hammer that does subside if I reduce pressure with the gate valve (defeating the object of the renewal as my tank needs to fill quickly).

Searched this site & tried the 'water bucket' attachment & variations on that theme but no success. The thing still hammers even if I grasp the thing tightly.

Would I be better switching to a plastic one? Do they do them for high pressure? I would like an anti-syphon silencer as a bonus.

Any advice/recommendations?

You need to fit an equalibrium ballvalve

Would that be something like a Torbeck valve? Are these suitable for high pressure into a cold tank...I thought they were for toilet cisterns?