Here's a good online coil calculator. I've found it to be quite accurate, as long as you input the correct info of course. Using it I find I can get within 0.15 ohm or so on a coil design I've never made before.
Hope this helps.
Thanks for the info, I actually have that bookmarked. I havent used it because Im confused how it works I guess. It says in order to get to 0.5ohm with 30 gauge round, you only need 2.37 full wraps?? I dont understand that, considering what Ive wrapped and always get the same results. I thought the smaller (width- like micro coils) and around 8 wraps got .5 and under? Im confused...