Jacketed bullet accuracy with the larger (oversize) lapped bore

[tacotime]

Veral, specific to this Redhawk, with the bore having a bore thread choke at about .4295 at the breech, I started but have not finished fire-lapping the choke out.  Throats are about .4327, so I am looking at using .432 or .433 cast bullets. 
 
My question is, with the bore approaching .430, if I or someone else decides to go back to .430 jacketed bullets and the bore is no longer .429 but pushing .430, do we expect accuracy with jacketed (or any other) .430 bullets to decline? 

Thanks!

[Veral]

No matter the caliber or type of gun, I have yet to hear of anyone degrading accuracy by lapping a barrel it is was oversize for jacketed.  Everyone to date has reported better accuracy than before, and less bore fouling.   

  Just relax and lap till the bore holds a push through slug tightly and makes it slide smoothly for the full length when pushing from breech to muzzle.

  A precision barrel, both in size and straightness and bore finish will out shoot the oversize barrel, but the oversize barrel will be the best it can ever be if lapped.

  Perhaps of extreme interest on this matter.    Freedom arms has always put oversize barrels on their super quality revolvers, but they shoot very well because they line bore the cylinder throats to tight jacketed bullet tolerances.  This guides the bullets into the oversize barrels nice and straight with no tip, and the rifling lands can then hold the bullets quite straight.   These guns will shoot even better with a barrel that hugs the bullets tighter, but Freedom Arms does this to reduce pressures which are very high with the 454.    By the way, I am speaking only about their 454.   They have many other chamberings now, which they may treat differently, and also may have changed their ways with the 454.  I haven't heard either way about this in the last 10 years or so, but did a LOT prior to that.

[tacotime]

It has been very interesting to learn about revolvers at a level most folks don't venture into.  Thanks again!

[Veral]

  A VERY good question because it concerns everybody who is considering lapping a barrel.
 
  The answer is:  The gun will shoot better with standard jacketed after lapping than beore lapping IF CYLINDER THROATS ARE NOT ENLARGED!  If cylinder throats are enlarges as part of the process, accuracy will fall off some and possibly quite a bit., because, if a bullet is allowed to tip at all on takeoff, it will remain tipped  all the way to the target.  The forcing cone and barrel cannot straighten them out no matter how they are configured.

  You will not be opening up throat on this Redhawk because they are already large and letting jacketed bullets to tip .  But the tipped bullets are hitting a rough bore, choked at the start and looser as they travel..   Oh yes.  Accuracy will improove with lapping, but it won't be as good as a revolver with cylinder throats which hugged the jacketed bullets tightly and a barrel that was perfectly true and hugged them also.  But you can't buy a gun like that, so I tell people how to fix what we can buy.

  Now, if you would just stoop so low as to start casting your own, and order up a mold from LBT, lube etc, that Redhawk which you want to shoot so badly would be capable of at least 2 inch groups at 100 yards and possibly an inch at 100 yards, but the shooter does have to point the gun in EXACTLY the same general direction before fanning the hammer!