A bowling magazine is a great idea, BUT before you get too carried away with planning the content, research very carefully how you are going to get the magazine "out there".
A big problem is going to be distribution to get your magazine to the bowlers, and its just not a matter of walking into a book shop and asking the proprietor to sell them.
We used to run a small business that sold general groceries and also a lot of womens magazines, and also other popular mags including motoring, gardening, etc. The sale of the magazines was very much manipulated by the distributors. The mags were all on a sale or return basis, for instance if we had 6 copies of Womans Day delivered one week and returned five, the following week we would be cut back by the distributor to receiving only 3 to sell. If you look at any shop selling magazines, the shelf space is huge and it has to make a good profit to pay for that space, so the retailer is not going to keep mags on the shelf that dont sell or accept from the distributor magazines with a very small percentage of market interest. What I mean by this is say 70% of our customers would buy Womans Day, but only 5% would buy a gardening magazine. I doubt whether many of our customers would have even picked up a bowling magazine, so we would not have asked to receive them from the distributor.
You have to find places to sell enough magazines to make enough profit to produce the next one at least. Everyone involved in bowling will want to be in the first magazine, or to read it, but after that interest will wain, maybe only 50% will buy next time (and the remainder of us will bludge it off a friend). If you can get bowling centres to sell your magazine, they are going to want a piece of the profit, and most centres will only put out stuff that will encourage people to bowl in their centre.
I dont want to put a "dampener" on your great idea, before you get too far down the track with content, just think about how much time and effort it is going to take and the costs involved to get advertisers every month, print, distribute and sell it.
Good luck with your project.