we've settled on using the 11 degree cutter over the years as it works the most, and best of the ones we tried...when there is little or no forcing cone in the breach end of the barrel, any and a little bit helps, as noted above, any off set or misalignment can and will be very noticeable, with NO cone or in fact hardly any, and we've seen quite a few of Rugers that had shallow, little or NONE ,like they cut off the barrel and let it go???? It does help & works.
any doubt, try it first, yes if you have to go out and buy the set, it is a bit pricy,but we've had ours for YEARS and its paid for itself over and over.
Its cheaper to get the job done, hopefully you have a decent (and fair) smith in your area, and if you make "freinds" with any of these guys, it pays off in the long run.Too many of these 'tools, jigs, and stuff" (gimmicks??) are only good if you are "in the business" and can justify the expense, and in X-number of jobs, make it pay for itself...............I priced some reamers recently and said NO WAY!!When I 'retired' I gave lots of that stuff to my gunsmith, but just hate to take that LONG ride into town, and even "bother" him he's so "busy", I have often told him I cannot afford him any more......... :roll: ( I just wait till the next show and get with some of the other "retired" smiths.....) 8)