ExtremeVel has the pressure/bullet called right on the bullet profiles. The bullet material , weight and the bearing surface all contribute to the pressure curve. The length of the bullet that is actually full diameter is a point to watch. An extreme example is the .38 full wadcutter. The whole length of the bullet is bearing surface, so you need LOT's less powder than a conventional bullet of the same weight and material.
If you find the bearing surface of the jacketed bullet you want to use is the same as the same weight of Winchester hollow point bullets, you can be confident the pressures will be about the same at the same load level. ExtremeVel used the term profile, which has a direct link to the bearing surface. To expand what he said, a 180 grain jacketed bullet with 8mm of bearing surface could have a round nose, hollow point, flat nose or pointy nose and still have the same friction coefficient.
As already mentioned, the plated bullets cannot be directly substituted for jacketed bullets. You really need to think of a plated bullet as a cast bullet lubricated with copper instead of the normal wax based bullet lube. They are relatively soft and have about the same bore sealing characteristics as a cast bullet. You can push them a little faster because the copper is a better lube than wax based lubes, but not much.
I am using 180 grain hard cast bullets from MasterCast in PA. I have used Missouri cast bullets and they are good too. For plated bullets I use 165 grain and 155 grain Rainier. I load them to just a couple tenths under the start load for a jacketed bullets. They are fine at that load level. If I try to push them harder, the accuracy goes away and pressure signs start to appear. For true Jacketed bullets, the Remington Flat nosed 180's shot good at just slightly above the middle of the spec loads. The accuracy was going away and the primers were showing pressure signs any where near the top loads, so I backed down. The Sierra 165 grain Sport masters shoot great all the way from the bottom of the load data all the way to the top. With Winchester primers I have actually shot a little over spec in my Para .40, and other than a nasty recoil, the Sierras seem to like it up there.
Anytime you feel your information is close but not perfect, start 10% down from the MAX that you think it should be a test it before you load too many. Too weak of a load can cause problems also. Watch each shot and inspect each piece of brass at first. I would rather take apart 20 loads that are not quite right than break a pistol (and maybe loose a finger) trying to use the bad loads up. Good Luck
If you find the bearing surface of the jacketed bullet you want to use is the same as the same weight of Winchester hollow point bullets, you can be confident the pressures will be about the same at the same load level. ExtremeVel used the term profile, which has a direct link to the bearing surface. To expand what he said, a 180 grain jacketed bullet with 8mm of bearing surface could have a round nose, hollow point, flat nose or pointy nose and still have the same friction coefficient.
As already mentioned, the plated bullets cannot be directly substituted for jacketed bullets. You really need to think of a plated bullet as a cast bullet lubricated with copper instead of the normal wax based bullet lube. They are relatively soft and have about the same bore sealing characteristics as a cast bullet. You can push them a little faster because the copper is a better lube than wax based lubes, but not much.
I am using 180 grain hard cast bullets from MasterCast in PA. I have used Missouri cast bullets and they are good too. For plated bullets I use 165 grain and 155 grain Rainier. I load them to just a couple tenths under the start load for a jacketed bullets. They are fine at that load level. If I try to push them harder, the accuracy goes away and pressure signs start to appear. For true Jacketed bullets, the Remington Flat nosed 180's shot good at just slightly above the middle of the spec loads. The accuracy was going away and the primers were showing pressure signs any where near the top loads, so I backed down. The Sierra 165 grain Sport masters shoot great all the way from the bottom of the load data all the way to the top. With Winchester primers I have actually shot a little over spec in my Para .40, and other than a nasty recoil, the Sierras seem to like it up there.
Anytime you feel your information is close but not perfect, start 10% down from the MAX that you think it should be a test it before you load too many. Too weak of a load can cause problems also. Watch each shot and inspect each piece of brass at first. I would rather take apart 20 loads that are not quite right than break a pistol (and maybe loose a finger) trying to use the bad loads up. Good Luck
Last edited:
