Did you do any cleaning when shooting? This has a lot to do with it. All my inlines are Lightning Bolts and shoot great with (2) 50 grain Pyro Pellets with a 250 gr Shockwave with 209 Remington Kleenbore primers. I usually swab every 2 to 3 shots as the it gets fouled up quick with Pyrodex whether pellets or loose. I have a Bushnell Banner 3-9 scope on my rigs and all the rings and bases are lock tite down. Was there any wind when you were shooting? Moisture/rain? What was the temp outside?