Does anyone know if the Superposed guns built in the 1960-1975 time period had the same slightly undersize bore diameters as the pre-1960 guns had? For instance, the pre-1960 guns in 12 ga. would be .725-.727 instead of .729 or larger. Thanks, Sandlapper

The seven I had dated from 1965 through 1972 all measured 0.724–0.725. And a 1983 Superlight measures 0.725. Still have four of them.

Jack O'Connor's "The Shotgun Book" (1965) listed standard bore diameter and choke constrictions for Browning, Winchester, and Remington. 12 gauge, as stated above, was .725. Remington and Winchester were both listed as .730.

Brownings of that era also had more constriction for a given choke than did Winchester or Remington. For example, Mod on a Browning 12ga was .024. Win and Rem were .016 and .018 respectively. Also true right down the line for the other gauges (16 and 20) as well. IC in a Browning 16 was .016; .007 and .008 for Winchester and Remington.

Guys, Thanks for the information. I love this site for the depth of knowledge of so many of its participants. It seems as though Browning would have modified their bore measurements in the late sixties to compensate for the wider usage of plastic hulls and power pistons, but I suppose ammunition worldwide did not change as quickly as it did in the U.S. This explains why the two Superposed 20 gauges I had seemed to powder claybirds so well.Anyway, thanks very much for the replies. Sandlapper

They would be im metric sizes not imperial so equivlents would be 724" 728"

My '66 trap gun has bores that measure 0.725+/-0.001. Chokes are 36 and 37 mils, about nominal.

My 1973 (S73) Superposed Trap gun, with very blond stock. Using my Skeets Bore Gauge:
Over barrel: 0.727" at 9" from standing breech and 39 points at muzzle.
Under barrel: 0.7265" at 9" from standing breech and 31 points at muzzle. The fourth digit past the decimal is a SWAG by eye.
Love that mechanical trigger.

Being a skeet shooter, I like the New Model Skeet Gun so I have several salt-free guns from those years dreaded by the purests. I have three 12-gauges, a 68, 70 and 72. The bores all measure in the .723" to .725" range.