ruger #1 45/70

[Frank46]

Veral, many thanks for answering my questions on my ruger #1 in 45/70. The only bullet that even comes close to filling the throat is the lyman 480 gr gas checked bullet. Most of my other molds will barely cast to .458. This one will do .459. Will this be suitable to lap out the bbl with your lapping kit?. thanks again. Regards Frank

[Veral]

  The lap compound in my lap kit increases bullet diameter about .002 when applied correctly, so your answer is yes.
   
   Understand that the charged lap bullet should be slighly larger than groove diameter at it's largest point, as it will be removing a small amount of metal at the largest point to make the barrel perfect.  We don't need to clean up all visable impressions in a bore, just knock the protruding roughness down flat to provide a smooth sliding surface for the bullet.  Little tool marks and rust pits, don't hurt performance compared to a perfectl shiny bore surface.

[Frank46]

Veral, I'm guessing that once the lapping has been accomplished, and new bore dimensions figured out by slugging then its time to get a new mold?. Still want one in the 400 grain weight. Frank

[Veral]

  Since chamber dimensions won't change, you probably won't go wrong ordering the largest diameter that will chamber freely.  However, if by chance your barrel gets too large, neck turning the brass to allow  slightly larger diameter bullets may well be worth the effort, in which case waiting to see what the bore diameter turns out to be after lapping may be a wise choice.

   I don't believe Iv'e mentioned it before on this forum, but when the case neck is to be used as the bullet alignment, as I prescribe for 45-70 , 30-30 and all similar long necked cartrides where the rifles have short throats, uniform neck thickness can make quite a dramatic difference in accuracy, if a lot of brass is worse than normal.  Forester makes an excellent hand turning tool for about $50.  It will cure tight neck throatings as well as brass with neck thickness not uniform.  Most brass I've measured is out .001 or .002 thousandths inch, which doesn't seem to hurt, but if out more, it is wise to turn the brass, which is far more precise than inside neck reaming.