. Does anyone have any ideas? Is there a way I can modify the BPS to shoot more accurately?
Thanks for any help.
Yes. Have the barrel pinned to the receiver by a gunsmith. That's basically what Tar-Hunt does with their 870 conversion. You can have the gunsmith permentally pin it or make it removable like mine by placing a removable screw in it.
I have my Rem 1100 20ga drilled and tapped with the forward hole on the Weaver mount going all the way through the receiver and barrel sleeve. A removable screw pins both together. To clean or change barrels I remove my scope via quick detach rings, then remove the screw. If yours is just a dedicated slugger then you can have the barrel permentally attached and clean with the barrel on.
Check Ithaca also. They're back in business from a new plant in Ohio.