In .44 Magnum, I was testing 12 BNH 240g SWCs (standard wax lube in the grooves) out to 1300fps with no significant leading. I stopped there as really 1200fps was as fast as I wanted to go. General loads in my .44 Magnum revolvers is a 1100fps load. That said, if you aren't getting leading at 1100fps, then you can easily push past that in 'that' revolver. All revolvers are different.... And when you start seeing signs of leading you can back off . No harm no foul when testing! Just a little elbow grease at times .
As for the bullet fit, it should ALWAYS match the throat(s) in the cylinder. Then the throats should be at least .001 over the size of the bore. Never less (why we sometimes have to open up the throats with a reamer). The bore should have no major constrictions (why sometimes we have to firelap the bore). If these conditions are met, you have a good chance of no leading regardless of the bullet hardness (up to a point).
As for pressure, the pressure should be enough to cause the bullet to 'bump up' for a tight fit in the bore. That's why 'hard' bullets sometimes will lead the barrel and softer ones do not. On the other hand if the bullet is to soft for the pressure-velocity, it could 'skid' in the barrel as it is forced to rotate via the rifling in the barrel and cause leading. A bullet that doesn't bump up or is to small will cause the hot gasses to go 'around' the bullet and vaporize the lead leaving deposits.
It's a game, but if all conditions are met, leading is a non issue no matter what fancy lube (or not) used. All I shoot is plain o' lead bullets with the 'wax' (red or blue) in the lube grooves. My two and 1/2 cents.
And then some people just shoot jacketed and miss out on the game entirely .
As for the bullet fit, it should ALWAYS match the throat(s) in the cylinder. Then the throats should be at least .001 over the size of the bore. Never less (why we sometimes have to open up the throats with a reamer). The bore should have no major constrictions (why sometimes we have to firelap the bore). If these conditions are met, you have a good chance of no leading regardless of the bullet hardness (up to a point).
As for pressure, the pressure should be enough to cause the bullet to 'bump up' for a tight fit in the bore. That's why 'hard' bullets sometimes will lead the barrel and softer ones do not. On the other hand if the bullet is to soft for the pressure-velocity, it could 'skid' in the barrel as it is forced to rotate via the rifling in the barrel and cause leading. A bullet that doesn't bump up or is to small will cause the hot gasses to go 'around' the bullet and vaporize the lead leaving deposits.
It's a game, but if all conditions are met, leading is a non issue no matter what fancy lube (or not) used. All I shoot is plain o' lead bullets with the 'wax' (red or blue) in the lube grooves. My two and 1/2 cents.
And then some people just shoot jacketed and miss out on the game entirely .
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