Nice to have a standard bore size. There are some .450" and .451" bullet moulds.
I have found that if an oversized bullet (.457" or .458") is first lubed, that it can be sized down as much as .010" and
maintain it's integrity. (no distortion) This, in itself, will the list of possibilities.
If grease grooved bullets are used and accuracy suddenly goes away,unbreech it and you will probably
find the grooves are full of lube and hardened powder fouling and that will prevent the proper upset of
the bullet on ignition.I found this out from the rifle I cobbled up in 2001 using a GM 450-458 barrel with
a 1 in 18 twist.The bullet was a 560 grain 458 grease grooved type from a custom mould sized to .4505
and 75 grains of GOEX 3fg sent it down range with good accuracy at 500 meters.I did not clean between
shots and I am sure that was a contributor to the fouling problem.I was too lazy to make a mould for a
paper patched bullet and used the old Lyman 451112 Sharps Bailey bullet in my Henry barreled Whitworth
and shot it for 11 years with no trouble.I think the sizing of that custom bullet wiped off too much lube and
the 451112 was shot as cast and weighed 485 grains.
I made the lock for this gun as well as the sights and used Don Brown's breech and precarved stalking rifle
stock because I had a correct trigger guard and it was good looking.I shot it against large caliber breech
loaders and won at 500 meters shooting from a rest.
Bob Roller