I only have this problem with my longbow. I never have it happen with my recurves. the string comes all the way forward and hits the bone between where my wristwatch would sit and the base of my thumb. This is not the forearm whack that we are familiar with! Could it be as simple as brace height being too low?

Brace height does sounds like the answer.

I agree,  Increase your brace height and check that your nocks are not too tight on the string.

Didnt think of the nocks...thnx.

Its a brace hight prob.... what is the brace hight now ?????