Allowable materials for air pistol grips?

[henrya]

I plan on building up my LP10 grips for a better fit to my hand. Would a semi-flexible material like cork or minicell hard foam be allowed? Would grip tape be allowed? Skateboard tape? (sandpaper like adhesive paper). Yes, I have looked at the rules I could find on-line.

Your suggestions will be appreciated.

[SamEEE]

No rules on material of the grip in the rules, but it needs to be safe.

[j danielsson]

If it's soft enough for your hand to form it, l would say no.
You would get a curve in the not allowed direction on the palmshelf.

[TenMetrePeter]

I'm not sure a soft material would give a stable grip anyway at 10m air pistol. It needs to deal with moist hands too.
Most people would use a slow hardening 2-part epoxy putty of which there are many brands. Form with a latex gloved hand and stipple with a carpenters nail while soft .
Of course what feels good at the time may feel bad next day. Its also very easy to suspect the grip when its just plain technique - I should know, I never had any.
Medium grit sandpaper glued on the shelf should be within the rules.