I recently purchased a repro. Krag three-piece cleaning rod set from Numrich for about $17.  They had sent me a coupon that pretty much covered the postage.  My intention is to carry it in the butt-trap of my 'range gun'.  Today, I got around to comparing it with an original.  (I have gotten a bit suspicious of the "originals" that are always for sale on ebay by a couple of vendors).  In the attached photos, the original is at the top.  Years ago, I got the original along with a muzzle/sight cover and oil bottle for $15 at a gun show.  Fortunately and ethically, the repro. has dimensions that differ from an original.  Original:  Main rod diameter=.200 inches.  Max. thread diameter=.158 to .160 inches. TPI=30.  Reproduction:  Main rod diameter=.195 to .199 inches.  Max. thread diameter .152 to .155 inches.  TPI=32.

Notice that the heads of the originals are completely uniform, while the repros are totally random - probably Chinese s**t.

And, aside from honest wear, many originals will show mushrooming from long periods of time rattling in a stock.

Oilers are common, but muzzle covers are probably one of the hottest items around - used to be a $10 item, now they bring much more. Glad I bought mine early - couldn't afford to equip my rifles today.

Thanks for posting this.  Nice to see what to look out for in the repro.  So far I've found an original rod in the butt of one rifle, and an oiler in another.  Still hoping to stumble on a muzzle cover in someone's "junk parts" box at the next gunshow.  I can't get myself to pay the current "market" price for one.