There were of course dedicated inanimate and live bird doubles with parallel MC stocks, BTFE and even (oh the horror

) ventilated ribs.
Hunter Arms introduced the Double Barrel Trap in 1920 with the 'Trap Package'; BTFE with reinforced barrel lug, AE, Hunter One-Trigger, recoil pad (usually Jostam or Hawkins), and twin ivory beads. The vent. rib was introduced in 1925. With a 32" barrel is only weighed 8 - 8 1/4 # however
The turn-of-the-century live bird competitors used guns limited to 8#, and often less
March 2, 1894 Riverton vs. Carteret
Fred Hoey - Purdey, 7# 8 oz., 48 gr. “Schultz”
Charles Macalester - Purdey, 7# 5 oz., 50 gr. “Schultz”
Capt. A.W. Money - Greener, 7# 8 oz., 45 gr. “E.C.”
George Work - Purdey, 7# 8 oz., 48 gr.
Edgar Murphy - Parker, 7# 6 oz., 42 gr.
T.S. Dando - Parker, 7# 6 oz., 3 1/2 Drams
H.Y. Dolan - Scott, 7# 8 oz., 48 gr.
R.A. Welsh - Churchill, 7# 9 oz., 49 gr.
Murphy's was 3 Dr. Eq., but the others' were 1 1/4 oz and 3 1/2 Dr. Eq., which in an 8# gun would have 27 ft/lbs of free recoil.
1 1/8 oz. at 1200 fps in a 10 pound trap gun = 16.2 ft/lbs
This fella did pretty good with his Smith double, but most of would do better in competition with dedicated trap guns.
Good thread
Side by Side Trap Shooters