Thread: Somethings wrong

I had a barrel removed from an honest 3 shot 1/2 to 3/4 inch rifle. I mucked with another caliber for awhile didn't use it much then sold the new barrel and had the old one, the one I'd taken off screwed back in.
The problem now is I took it out this morning fir the frist time aver having the original barrel put back, used the same ammunition but cannot get any more than 2.5-3.5" three shot groups
It has the same barrel, same stock, same action , same scope, same rings, same rail.

Only difference is the barrel has been taken off then put back on
I do notice the screws where the open sights were don't line up straight like they used to, are off ever so slightly to the left.
Would this be usual? and another load have to be developed, or is something else wrong.

Thanks.