So I'm about to compete in a comp with a standard Air Arms HFT500.
I've never competed before & i'm a bit unsure of some of the rules.
I gather there is a problem with the standard concave stock on the HFT500 (concave not allowed?)
I know lots of people compete with a HFT500, so what do they do?
Fit some kind of slip on cover? or remove the concave stock?

I usually shoot with the front of the rifle in a V shaped tripod, which again I believe isn't allowed?
I gather the front of the rifle can only be supported on a flat surface (so no bean bags or V shaped supports)

Any other rules & regulations that I should be aware of?

All help greatly appriciated.