The hitch is often the feed ramp of the gun or the magazine. A round nose bullet is difficult to headspace on the bullet in many longer 1911 chambers because it either makes the cartridge too long to fit the magazine or too long to turn the corner smoothly at the top of the feed. I've never had a problem with either H&G 68 shape SWC's nor with the shorter SWC shapes like the Lee molds have, nor with the 185-grain RCBS mold I have for a near wadcutter with a small bump of a round nose, though I did have to radius my feed ramp for that one, as it's about like feeding an empty case (which that gun will do after the ramp mod).
Some of the old-time Bullseye shooters also used a roll crimp into a bullet, especially with swaged bullets, for which it could dig in. Theory says that such a crimp is dangerous because it could wind up trying to open while wedged in the case mouth. But if the bullet is out far enough to headspace on the bullet, then that's no issue because the case mouth can't go that far into the chamber. They claimed the added start pressure plus the start into the bore produced by far the most accurate loads they could get from those bullets.
USSR, the problem with any fixed value of lead protrusion from the seated round (I've always read 0.020", or a thumbnail thickness forward of the case mouth, but the same principle) is it assumes all guns have the same headspace. They don't, especially not a bull's eye gun that has had a throating reamer applied after initial fitting to steepen the taper angle onto the lands. If you cut your own chamber to headspace at SAAMI minimum with the barrel locked up in your slide, then what you describe will work because it will pretty much guarantee the bullet has at least started into the throat even if it isn't headspacing on the bullet. That's the thing that brings about the accuracy improvement. But once you've got some cases that have seen twenty reloads and are now shorter than SAAMI minimum, you hit a point where you either headspace the extractor hook or on the bullet before the case mouth gets to the end of the chamber. I decided long ago just to start out headspacing on the bullet and stay that way through the life of the case.
I once ran a batch of 1000 Winchester cases with target loads until they reached 50 reloads. By that time only about 300 hadn't either split or been sacrificed to the range gods. The headstamp markings were getting slowly hammered into barely visible condition. All of them were about 0.025" shorter than when they were new. About half a thousandth lost per load cycle. That's because the .45 Auto doesn't have enough pressure to stick the case to the chamber wall, which is a prerequisite to stretching during firing. By that time, if I weren't headspacing on the bullet, the extractor hook would be shouldering the whole burden and accuracy from the bullets heading down the tube slightly off-axis would open the groups up about 40%.
Engraving is what is called a term of art in the firearms industry, and is standard nomenclature. You can look it up in the SAAMI glossary of industry terminology under "Bullet Engraving". It is not a good physical description, as you observe, but neither is molding, as that implies melting the metal and pouring or injecting it into a mold. A better technical description of the actual action is swaging, with the throat and bore and rifling acting as the swaging die.
The hardness issue is something you simply have wrong because what your imagination is telling you about it does not match the magnitudes of what is actually happening. That's common. It's why they taught us analysis at engineering school; to unfool ourselves.
To get a sense of the difference, QuickLOAD uses 1160 psi as starting pressure for cast or swaged lead bullets, rifle or pistol. For jacketed pistol bullets, it is 2175 psi. They are wide enough and the jackets thin enough that they are easier to swage than rifle bullets, for which it uses 3625 psi, nor for solid (not banded) copper and for jacketed bullets over hard cores, it uses 6525 psi, and for jacket bullets jammed into the lands, it is 10,825 psi. Those are the start pressures that cause the powder burning model to match what you see with a pressure measuring instrument. I have made the same measurements by the strain gauge method and verified these numbers are in the ballpark, though thin jacketed match bullets and heavily jacketed hunting bullets can be tweaked to have their own numbers. In all cases, swaged or cast lead bullet alloys have the lowest values.
But, don't take my word for it or the word of QuickLOAD's author. Anybody can be proved wrong. Just do the following experiment to see for yourself:
Take your pistol barrel out of your gun. Run a patch oiled with Mobile 1 0W-20 or STP down the bore so it isn't dry. Hold the muzzle against a wood block while you drive a cast bullet into its throat with a brass dowel and a hammer. Get a good feel for how much effort it takes to get it through and out of the muzzle. Now run the oily patch through again try to do the same thing with a jacketed bullet. Don't do the jacketed bullet first as it is possible to stick a jacketed bullet in a barrel and spoil the comparison. You may decide from the early feel of the jacketed bullet that you want to stop and knock it out from the front before you get it fully into the lands. The lubricant should prevent it sticking badly, but do the cast bullet first, just in case. Sometimes stuck jacketed bullets have to be bored out with guided drills. Harold Vaughn measured about 1200 lbs of force required to push a .270 bullet through a rifle barrel with a hydraulic press. But even assuming it goes through, you will find it takes significantly more effort.
Some of the old-time Bullseye shooters also used a roll crimp into a bullet, especially with swaged bullets, for which it could dig in. Theory says that such a crimp is dangerous because it could wind up trying to open while wedged in the case mouth. But if the bullet is out far enough to headspace on the bullet, then that's no issue because the case mouth can't go that far into the chamber. They claimed the added start pressure plus the start into the bore produced by far the most accurate loads they could get from those bullets.
USSR, the problem with any fixed value of lead protrusion from the seated round (I've always read 0.020", or a thumbnail thickness forward of the case mouth, but the same principle) is it assumes all guns have the same headspace. They don't, especially not a bull's eye gun that has had a throating reamer applied after initial fitting to steepen the taper angle onto the lands. If you cut your own chamber to headspace at SAAMI minimum with the barrel locked up in your slide, then what you describe will work because it will pretty much guarantee the bullet has at least started into the throat even if it isn't headspacing on the bullet. That's the thing that brings about the accuracy improvement. But once you've got some cases that have seen twenty reloads and are now shorter than SAAMI minimum, you hit a point where you either headspace the extractor hook or on the bullet before the case mouth gets to the end of the chamber. I decided long ago just to start out headspacing on the bullet and stay that way through the life of the case.
I once ran a batch of 1000 Winchester cases with target loads until they reached 50 reloads. By that time only about 300 hadn't either split or been sacrificed to the range gods. The headstamp markings were getting slowly hammered into barely visible condition. All of them were about 0.025" shorter than when they were new. About half a thousandth lost per load cycle. That's because the .45 Auto doesn't have enough pressure to stick the case to the chamber wall, which is a prerequisite to stretching during firing. By that time, if I weren't headspacing on the bullet, the extractor hook would be shouldering the whole burden and accuracy from the bullets heading down the tube slightly off-axis would open the groups up about 40%.
Northof50 said:
Engraving is what is called a term of art in the firearms industry, and is standard nomenclature. You can look it up in the SAAMI glossary of industry terminology under "Bullet Engraving". It is not a good physical description, as you observe, but neither is molding, as that implies melting the metal and pouring or injecting it into a mold. A better technical description of the actual action is swaging, with the throat and bore and rifling acting as the swaging die.
The hardness issue is something you simply have wrong because what your imagination is telling you about it does not match the magnitudes of what is actually happening. That's common. It's why they taught us analysis at engineering school; to unfool ourselves.
To get a sense of the difference, QuickLOAD uses 1160 psi as starting pressure for cast or swaged lead bullets, rifle or pistol. For jacketed pistol bullets, it is 2175 psi. They are wide enough and the jackets thin enough that they are easier to swage than rifle bullets, for which it uses 3625 psi, nor for solid (not banded) copper and for jacketed bullets over hard cores, it uses 6525 psi, and for jacket bullets jammed into the lands, it is 10,825 psi. Those are the start pressures that cause the powder burning model to match what you see with a pressure measuring instrument. I have made the same measurements by the strain gauge method and verified these numbers are in the ballpark, though thin jacketed match bullets and heavily jacketed hunting bullets can be tweaked to have their own numbers. In all cases, swaged or cast lead bullet alloys have the lowest values.
But, don't take my word for it or the word of QuickLOAD's author. Anybody can be proved wrong. Just do the following experiment to see for yourself:
Take your pistol barrel out of your gun. Run a patch oiled with Mobile 1 0W-20 or STP down the bore so it isn't dry. Hold the muzzle against a wood block while you drive a cast bullet into its throat with a brass dowel and a hammer. Get a good feel for how much effort it takes to get it through and out of the muzzle. Now run the oily patch through again try to do the same thing with a jacketed bullet. Don't do the jacketed bullet first as it is possible to stick a jacketed bullet in a barrel and spoil the comparison. You may decide from the early feel of the jacketed bullet that you want to stop and knock it out from the front before you get it fully into the lands. The lubricant should prevent it sticking badly, but do the cast bullet first, just in case. Sometimes stuck jacketed bullets have to be bored out with guided drills. Harold Vaughn measured about 1200 lbs of force required to push a .270 bullet through a rifle barrel with a hydraulic press. But even assuming it goes through, you will find it takes significantly more effort.
