Hitting your forearm is not a bad thing! How's your arrow flight. If you look at pics of Howard Hill shootin, he has an arm guard on, even in the summer with his shirt off! I have longbows I shoot and hit my arm. Check and measure the slap mark with the string height, and that will tell how much stretch your gettin after the shot. And it can be a tuning issue, arrow spine and such. In masters of the Barebow vol. 2,a gentleman is shooting a real high brace height on his longbow , try it it might work! There's nothing set in stone. Good shootin, Steve