Swap out barrel on Ruger No 3

Rich,

Having switched around several Ruger single shot barrels I would give it fair odds.  Some "adjustment" can be obtained by how tightly the replacement barrel is screwed in.  In my opinion, Ruger factory barrels are screwed in too tightly.   The single shot Rugers that I have re-barreled lately are only little more than hand tight.  I use LocTite on these and have seen no problems.  If by screwing it in as tightly as you can still doesn't give you correct "clocking" you can remove metal from the receiver front / barrel shoulder area.  Sometimes enough clearance can be gained by lapping the front of the receiver ring square.  Sometimes you need to remove some metal from the barrel shoulder.  Also, it is sometimes necessary to remove some metal from the end of the barrel where it contacts the falling block's face.  Sometimes lapping the block's face square will give enough clearance.  If too much is removed from the end of the barrel it can affect the chamber, possibly requiring that the chamber be "freshened" with a reamer.  Sometimes only the rim recess needs deepening.  My experience with factory #3 .30-40 chambers is that they are frequently so oversize that a little shortening only improves them.  The worst condition, in my opinion, is one in which the clocking goes past top dead center, and is just too loose to be cured by a lite tightening and LocTite.  To set back a full thread length is .0625".  Of course you would never set it back a full thread to clock it, but say maybe .050 or so.  In any event, it would still require reaming the chamber and deepening the extractor slot.  Another fix that is not classy but will work, without reaming chamber, is to make a shim washer to go on the barrel between the barrel shoulder and the receiver face.  A very thin washer, something under .010 doesn't work well in my opinion.  If say, you need to gain .005", use a shim .010 to ,015 thick and then relieve the barrel shoulder to get the correct spacing.

My opinion, the .30-40 was the best of the #3 chamberings.  Good luck.