Yes, you can most certainly go to a golf club manufacturer in an effort to negotiate exclusive distribution rights to their product/s. but I hope you have some idea of just how large your line of credit would need to be.
I'm thinking from what you have been selling that you may not quite be in that sort of position, just yet.
I was talking about second hand golf clubs to another member not so long ago and they were wanting to buy and sell from a Pro Shop, but of course the margin wasn't there.
At the time I suggested taking a look at the second hand market for that market, and my sourcing suggestion was the Pro Shops themselves.
Plenty of golfers trade in their equipment on new gear, and if you approached several Pro Shops about a wholesale purchase of all their traded stock, you could be offering them a solid business opportunity, as well as creating one for yourself.