Molly
05-11-2011, 10:05 PM
I made a very interesting observation this afternoon, and it raises questions of the effects of how deeply we seat cast bullets that I'd like to invite comments on.
Bear with me a moment while I give you the background for my question. At a recent gun show, I picked up an ancient and substantially rusted US Revolver Co. breaktop in 38 S&W caliber. But most of the rust was on the outside, the action operated smoothly, and the cylinder allignment 'wasn't too bad'. The price was really right and I needed a new toy, so I took it home, wire brushed the rust off, gave it a couple of treatments with OxphoBlue, and lubricated it. I even found TWO 38 S&W cartridge cases in my piles of junk, so I decided to try some special purpose loads for it. I'm sometimes annoyed by raccoons, and I thought I might be able to put together a load light enough that it wouldn't kill them (leaving me with a lot of blood and a dead raccoon to dispose of) but would emphatically inform them that their attention wasn't welcome on my patio.
To this end, I decided to load both cases with a single 000 buckshot (36 caliber) and a small charge of HP38, because I didn't want to strain the integrity of this old revolver. To start things off, I put 0.5gr (That's right: Half a grain) of HP38 under the first one, and went wild and put a full grain under the second. Then I took them outside and 'fired for effect' at an old bit of plywood. I think the main reason I shot at the plywood was to see for sure whether the buckshot made it out of the barrel. And it did, with both loads. The half grain load made a pretty good dent, and the full grain actually managed to stick. I saw where the shot from the half grain landed, so I picked it up out of curiousity. And this is where the real story begins.
The ball showed full engraving on one side, and almost none at all on the other side. This surpirsed me, because I sort of assumed that any slight cylinder / bore mis-allignment would be corrected by the force of the ball entering the forcing cone. Curious, I dug the ball from the full grain shot out of the board, and it was almost exactly the same: Heavy engraving on one side, and not even full engraving on the other side of the ball.
Now I know that if I push a buchshot through the cylinder and barrel with a hammer and a steel rod, it will engrave about equally on both sides. (I tried it!) The only explanation I can think of is that the buckshot picked up enough velocity and inertia from the off-center cylinder that it flattened and engraved on the one side instead of centering itself like the pushed ball did. This slight flattening as the one side engraved was enough to keep the other side from fully engraving. At least, that's the explanation I'm going with unless one of you can come up with a better explanation.
Now we come to the question this raises: If the inertia of even such light loads could overcome the natural tendency of a bullet (ball) to center itself in a hole, how much worse would it be for a medium to heavy cast bullet load in a rifle? Ideal designs like 311291 have a nose to center the bullet in the bore before it's fired. But what about Loverin designs like 311467? For ease of operating the bolt, they are generally seated somewhat off the leade. It might be argued that they receive decent allignment from the neck of the cartridge, but then it could also be argued that they have so much more inertia that the effect would be even worse.
Me, I dunno. I DO know that I get my best results (accuracy) with the bullet forced into the leade as the bolt closes. I never understood just why that was so, but it was demonstratably true. Now I think I might know WHY seating bullets hard into the leade gives better accuracy.
So with that, I'll throw the thread open for coments, alternative explanations and objections. Gentlemen, what say you?
Bear with me a moment while I give you the background for my question. At a recent gun show, I picked up an ancient and substantially rusted US Revolver Co. breaktop in 38 S&W caliber. But most of the rust was on the outside, the action operated smoothly, and the cylinder allignment 'wasn't too bad'. The price was really right and I needed a new toy, so I took it home, wire brushed the rust off, gave it a couple of treatments with OxphoBlue, and lubricated it. I even found TWO 38 S&W cartridge cases in my piles of junk, so I decided to try some special purpose loads for it. I'm sometimes annoyed by raccoons, and I thought I might be able to put together a load light enough that it wouldn't kill them (leaving me with a lot of blood and a dead raccoon to dispose of) but would emphatically inform them that their attention wasn't welcome on my patio.
To this end, I decided to load both cases with a single 000 buckshot (36 caliber) and a small charge of HP38, because I didn't want to strain the integrity of this old revolver. To start things off, I put 0.5gr (That's right: Half a grain) of HP38 under the first one, and went wild and put a full grain under the second. Then I took them outside and 'fired for effect' at an old bit of plywood. I think the main reason I shot at the plywood was to see for sure whether the buckshot made it out of the barrel. And it did, with both loads. The half grain load made a pretty good dent, and the full grain actually managed to stick. I saw where the shot from the half grain landed, so I picked it up out of curiousity. And this is where the real story begins.
The ball showed full engraving on one side, and almost none at all on the other side. This surpirsed me, because I sort of assumed that any slight cylinder / bore mis-allignment would be corrected by the force of the ball entering the forcing cone. Curious, I dug the ball from the full grain shot out of the board, and it was almost exactly the same: Heavy engraving on one side, and not even full engraving on the other side of the ball.
Now I know that if I push a buchshot through the cylinder and barrel with a hammer and a steel rod, it will engrave about equally on both sides. (I tried it!) The only explanation I can think of is that the buckshot picked up enough velocity and inertia from the off-center cylinder that it flattened and engraved on the one side instead of centering itself like the pushed ball did. This slight flattening as the one side engraved was enough to keep the other side from fully engraving. At least, that's the explanation I'm going with unless one of you can come up with a better explanation.
Now we come to the question this raises: If the inertia of even such light loads could overcome the natural tendency of a bullet (ball) to center itself in a hole, how much worse would it be for a medium to heavy cast bullet load in a rifle? Ideal designs like 311291 have a nose to center the bullet in the bore before it's fired. But what about Loverin designs like 311467? For ease of operating the bolt, they are generally seated somewhat off the leade. It might be argued that they receive decent allignment from the neck of the cartridge, but then it could also be argued that they have so much more inertia that the effect would be even worse.
Me, I dunno. I DO know that I get my best results (accuracy) with the bullet forced into the leade as the bolt closes. I never understood just why that was so, but it was demonstratably true. Now I think I might know WHY seating bullets hard into the leade gives better accuracy.
So with that, I'll throw the thread open for coments, alternative explanations and objections. Gentlemen, what say you?