Originally Posted by max38
Thanks for the reply P&P.
Only shoot lead, coated 158 gr SWC which leaded forcing cone consistently but only a small patch at 7 o'clock position which is why I decided to recut cone to 11 degrees, hoping to decrease leading and improve accuracy.
Went to range yesterday and definitely lost velocity with new cut as groups were all 4" low at 25 yards. Leading is much worse and around entire circumference of cone. No lead spitting and no lead on cylinder face or frame.
If you're getting leading around the entire circumference of the cone you probably have two things going on:
The bullet is too small (tight throats on the cylinder?)
That big funnel of a forcing cone is allowing a lot of gas past the bullet before it makes it to the rifling. That gas cutting of the bullet is the source of that leading.
You could check the throats and ream them if they are smaller than the groove diameter of your barrel. That may fix your leading if you're lucky.
If not, I'd consider getting that barrel set back a thread and re-cutting the breach face of the barrel (a flat 90 degree cut) to re-establish the correct barrel to cylinder gap. That may buy you enough distance to remediate that over cut cone.