There is more science to a shotgun then most believe...on the higher end stuff like the beretta and Brownings.they usually have lengthened forcing cones and true dimension chokes...they don't deform shot as much and and give much better patterns...
I hadnt used a pump in many years till recently...got a barn full of starlings so didn't want to take any of my Brownings to be farm guns so I took my old 870. Man I couldn't hit worth a crap ...starlings are fast and small...so I tryed an Ithaca 37....even worse...so I I measured the bore it's a tight full choke...so I lengthened the forcing cone and bored the choke to imp/mod...huge diffrance...I went form a 10 percent hit ratio to 50 percent...
