Clojure's custom map implementation using reduce

my-map.clj

(defn my-map
  ([f coll]
   (reverse 
    (reduce (fn [result x]
              (cons (f x) result))
            ()
            coll)))
  ([f coll & colls]
   (let [colls (cons coll colls)
         n (apply min (my-map count colls))]
     (loop [i n
            result ()]
       (if (zero? i)
         result
         (recur (dec i)
                (cons (apply f (my-map #(nth % (dec i)) colls)) result)))))))