Most of us have done a fair share of experimentation and patterning. Having shot a12 ga for years with large, fast loads i didn’t pay much attention to speed. If anything I opted for faster loads. After doing a lot of viewing on YouTube about faster loads it still didn’t affect me. In part because of the distance I tend to shoot (behind my springers) is typically between 25-35 yards. Rarely further.
About a year ago I bought a new Winchester SX4 in 20 ga to go with my sx4 in 12 ga. Spent the summer and early fall at the trap range. Found that mentally I felt weaker shooting loads 3/4-7/8 oz. At range on clays I just wasn’t taking as many birds. spent some time patterning different loads trap and hunting. Eventually I came to the conclusion I needed to tighten pattern. went to full choke and spent enough time at the range to gain confidence and numbers with my 12 vs the 20 we’re almost identica. Actually, even got a bit more proficient with the 20 due to tighter choke.
Last fall hunting NODak I brought out the 12 ga sx4. Windy weather but the first 3 birds were at about 30 yards. With modified choke and large load 1 3/8 oz, 1485 fps, #5 all three birds went down but all got up and moved. Frustrated at what I considered hard hits I decided to go back to the 20 ga. With full choke, 3 inch, 1 1/8 oz, 1200 fps, #5 the next 3 birds went down hard. No run, dead and done. The next 4 days I hunted using the 20 with great success.
I guess my point is know your gun, pattern your gun, use the correct choke for the job, and speed doesn’t always matter. I will spend sometime this summer with the 12 ga and tighten my choke a bit till I see similar performance at the range. Until last year I had never thought my primary shotgun would EVER be anything less than a 12 ga.