Can anyone help me with my mod 50?? bought recently & after replacing the mainspring & piston seal noticed that the transfer port size is larger than the bore?(it's a 1980 .22) the rifle shoots harshly & won't make more than 7.5ft/lbs . I suspect some previous owner has drilled the port out too big, does anyone know the correct size for the port? I was thinking of siver soldering an insert the correct size in or welding up the hole with mig & re boring it. Either way it's not going to be an easy fix.