I haven't seen any Marlin Ballard #1.5 with 3 groove rifling, and sure would be interested in seeing that! All I've seen were 6 wide grooves with narrow lands, and my #1.5 is the same. There's an excellent picture of the Ballard rifling on page 137 of John Dutcher's great book on these guns. The Ballard rifling didn't change, and was still in use in modern Marlin repeaters long after the Ballard ceased production by Marlin.
I would guess the .44 that Frank described was most likely either an #0 or #1 Ballard, and not a #1.5 model. The earlier models were assembled from Brown Mfg. parts, and would explain the 3 groove barrel.
My 1.5 is also a .40 caliber, a .40-63 Everlasting to be exact; also known as .40-70 Ballard. They also were made in .40-65 Everlasting, and .45-70
The #1.5 was the first Marlin Ballard made completely of newly manufactured Marlin parts, and the first firged frame Ballard. They came with round top receivers with flat sides, full round barrels, and straight grip stocks. Levers used were either ring type, early S with the tail turned under, or the typical S style used on many later Ballard rifles. They are very tough to find, and I just found the one I own this year, after 20+ years of trying to own one.
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