"The Hunters of Jungdai" was a science-fiction novel written by prolific writer Kenneth Bulmer, and published as one-half of an Ace Double, with the other side being Project Jove by John Glasby. It is part of a series called "Keys to the Dimensions", an interlocking story, although the other parts don't need to be read for this to make sense. Because, for one thing, it doesn't make sense.
Okay, this one is a mess. I have been studious in trying to find something good to think about all of these Ace Doubles. Sometimes I have to stretch a bit. Sometimes I saw it is creative. Sometimes I say it is professional. But then we come across a book like this. Our protagonist is walking down the street from his shooting club when two hot girls in sexy outfits stumble across him and take him across several dimensions in the first dozen pages, because there is someone called "The Contessa". I remember some of this from "The Key to Irunium", that I read two years ago. Then he gets stranded on a safari world, the titular Jundagai, where he becomes a tough guy who knows a lot about guns and is also a gigolo, but then at the end he hooks up with the dimension hopping hot girls in sheer clothing, and they all ride off together.
There is a certain amount of fisticuffs and trick shooting and scantily-clad warrior women that are part and parcel of pulp science-fiction. I don't object to those things. I enjoy them. There is also a certain amount of disconnected hodgepodge of science and technology and epochs that are part of these stories. But there, it all seemed so gratuitous and without a point, and the hero, such as he was, was a Marty Stu, that at a certain point I couldn't invest anything in such a silly story.
Also: the cover has a man in medieval battle armor, a submachinegun, and a bare chest, firing his gun in front of what seems to be a rainbow flag. Which seems promising, but this book isn't even entertaining enough to have a gay subtext. I have several more books by Kenneth Bulmer in my pile of Ace Doubles to be read, and I have to admit---I am not specifically looking forward to reading them.