Trouble trying to hold hammer to adjust spring tension...hatsan 44-10

Hi. I'm trying to adjust the spring tension on the hammer on a Hatsan 44-10 long. I have the Allen wrench up the hole against the hammer and when I try to adjust it lighter or heaver it just spins on the Allen wrench. Do any of you have any options that I can try now? Or am I missing something in the translation of how to do it? Any help would be appreciated.... thanks Richard
MOD EDIT: Moved to PCP section
 
I saw in your previous post you drilled your hole in the bottom of your stock. There is a small hole in the side of the hammer that your wrench has to fit into to keep it from turning. Either your drilled hole doesn't line up with the hole in the hammer or your wrench is to big. Remove stock if you have to & look into the hole while turning the adjuster wrench until you can see it line up. The adjuster wrench is 4mm & has to be long enough to reach. I had to cut a wrench in half & weld an extension in the middle to make one long enough.
 
Well I found the problem... or not problem... the spring tension was already at the lowest it could go....It was just jammed tight. I have it loose now Soooooo my nixed step is to learn how to change to a lighter spring??? Or lighten the hammer??? I'm not sure how to proceed now. I will keep looking at all the web sights you all pointed me to. Thanks again.