DaveT, you and Coffinmaker are easy to annoy.
Now, disregarding the barrel, I decided to look up "Clone" in Merriam-Webster.
Definition number 2 of the Noun version: "one that appears to be a copy of an original form"
and among the synonyms listed are: "copy, dummy, dupe, duplicate, duplication, facsimile, imitation, mock, reduplication, replica, replication, reproduction."
so...
FWIW I prefer reproduction or replica.
And I like octagonal barrels, thus my 4 '51 conversions.