https://www.midwayusa.com/product/91...hort-long-trac

it may not be related, but check the replaceable recoil buffer pad condition and replace them if damaged, the browning BAR is gas operated,
and use of slower burning powders does cause extra impact wear issues mandating the pads regular replacement ,
group size tends to get noticeably larger if they are damaged, I doubt this is related but certainly for the under $4 or so they cost replacing one won,t hurt.
personally Id suspect the scope mounts need to be replaced,

a steel one piece base
https://www.midwayusa.com/product/10...e-browning-bar
decent rings help
https://www.midwayusa.com/product/14...le-rings-matte


IVE had far more of these style linked below,mounts fail
https://www.midwayusa.com/product/13...ard-scope-base

https://www.midwayusa.com/product/13...standard-rings