I have a remington 521T .22 that groups 1-2 inches at 50yds. When I slugged the bore I found that the first 10 inches of the bore was very tight. After a thourgh cleaning I fired 1 group that went into one ragged hole and then went back to shooting large groups .When I slugged the bore again I found a tight area in frount of the chamber for about 2 inches. I have ordered your lapping kit. My question is, will the lapping ammo lead the barrel if I fire them or should I try to polish the barrel first?Also could the leading be caused by gas cutting?The chamber area seem to be .225.