You have it right when considering LBT bullets. Meplat percentage goes up as caliber goes up. LBT molds cavities are cut on a tracer lathe, a very special one I might add, that has 0 backlash. I had to build it to get what I wanted. The tracer stylis follows a 10 times oversize negative of one side of the outside profile of a bullet. So the outside shape of the bullet is fixed with any given profile. With the WFN the pattern has an ogive curve which is nine tenths of an inch less than the bullets bearing surface. This pattern is more than 10 times longer than any bullet that will be cut with it, so to cut a specific bullet the pattern is placed to give the desired overall length, and clamped in place. Check shank crimp and lube groove patterns are loose pieces which are then clamped in the appropriate places. This setup give me complete flexibility to produce bullets with any desired crimp groove to nose length, lube groove etc. In other words, every mold I make is essentially custom. If I'm lucky and get more than one order for the same bullet weight and caliber, perhaps only the check shank and lube grooves will have to be changed, or nose length or whatever, but each is custom.
Regarding weight. When I started making molds in 1981 there were only a few really heavy handgun bullets available and they would not consistently penetrate straight, this due to too small a meplat, a poor flight form, bad bearing design, etc etc, which also demanded 60,000 psi to get them up to enough speed where they would deliver the dreamed of power potential. At any rate, I determined to develop the heaviest most powerful and most accurate bullets ever made. With the new mold lathe and its flexibility I could make only one change at a time to a given bullet length and diameter. So I played with meplat size only to see what happened, then lube groove size and arrangement, nose length etc etc.
I worked 16 hour days 6 days a week for 6 months with this kind of development, which taught me what no other man in history had been able to learn about what makes cast bullets perform. I started selling molds then, but my testing and experimenting have never stopped, so I've learned a lot more. My best heavy weight 44 revolver bullets for example, with nose length set up to fill the cylinder of the gun of interest will produce more velocity than standard weight jacketed with essentially the same pressures. This if LBT bullet lube is used. I must add that I had already gone after the bullet lube thing with the same passion as I did bullet design. That cost us our complete life savings, and didn't pay back anything like I had hoped for, so during the mold making venture we lived on ' muckets and sawdust' if you don't mind the imaginary diet. We were poor enough that when our daughter was seriously injured in an auto accident we had to drive 400 miles and live on the contents of a fruit jar of coins we had collected over a few years, silver dollars 50 cent pieces etc.
So the bullets which I developed are far more powerful than has ever been possible before, with the most power gain in the 44 mag being with the 320 gr WLN and LFN with .5 nose in the longer cylinder revolvers like the Redhawk, where foot pounds energy is a full 3 times what factory jacketed bullet loads put out.
Now lets go back to the Kieth bullet which was the best cast bullet performer available when the heavy bullet rage started, the rage that inspired my bullet development. The Kieth was known for penetration through anything, with decent but not superb killing punch. As a side by side comparison in those early LBT days a very brief pressure test was done with a standard powder charge behind the 250 Kieth and my 250 LFN gc. The LFN left the muzzle with 50 fps more speed and did it with about 10,000 less pressure! If the pressure had been raised to equal that of the Kieth the LFN would have been delivering probably 200 fps more velocity or more. But the LFN meplat is the same as a REAL kieth, so penetration goes even farther off the chart than with the Kieth!
All this to answer your question about needing heavy weight bullets. I developed far too heavy weights for deer and elk hunters, which comprise probably 99% of my customers. And they KICK! But the Kieth kicked too much for most shooters, back when it was the thing, mostly because the S&W is more painful to shoot than many other revolvers. Therefore, I try to tone down what people buy so they get what klls like the hammer of thor out front, but not behind.
So, yes, penetration is being overplayed these days by gun writers who aren't really familiar with LBT designs or are locked unto old ideas. Ideas which put too much emphasis on the effect penetration has on killing power. Weight must only be heavy enough to maintain a high enough velocity when the bullet exits that the wound channel is large enough for rapid bleeding. Excess over that means intensified recoil that will only make bullet placement more difficult, and a properly placed bullet is the most important factor there is in taking game cleanly. I work hard to deliver just that whenever I make recommendations to my customers.
