I have a Black Widow KB 58" with a brace height of 8 3/4 and a Silver Tip with a brace height of 7 3/4 and I hit my arm with the Tip but not the KB. Is it because of the brace height?
If your Silver Tip is a recurve or longbow with a pistol grip riser then yes your brace height is probaly to low. If it's a straight grip then it could be that your not turning your elbow out.
Both recurves
Are you holding your bow in the web of your hand? Put the throat of your grip on the knuckle of your thumb when drawing your string will always clear.
I hold the bow the same on both bows.
Are you actually scraping the arm with force or just a small,red area?
I'm thinking maybe a little torquing of the bow,after,release.
I forgot to mention that the KB is FF and the Tip is B-50
Brace height maybe your problem specifically but with a proper grip the sting will always clear your arm regardless of brace height.
When I had that happen, low brace height was the problem. Remember, too, that B50 will stretch a lot longer before it settles in, and will always need to be checked for brace from time to time.
The other factor you may want to watch is putting a slight bend in your elbow of the bow arm. It will also keep you from pulling shots to the left on release (if you are right handed).