Professor,
What bullets were you interested in? As I wrote, the .38 and even .32 bullets can be made with the deep Lube Groove using what Accurate Molds will cut because they have relatively shallow groove depths. The rub is what happens with .38 WCF (.40 cal) and up. The grooves for those were 0.05" deep on the molds Dick was selling. We "can't get there from here" with the limitations of what Tom will cut.
The limiting parameters are:
- The Nose must be flat
- The Nose must have a diameter of at least Ø.180
- The Groove depth cannot be deeper than 0.03" per side
- The Side Walls of the grove cannot less than 35° to the normal (perpendicular to the axis) , It can greater than 35° as is the case with the crimp groove back side
I tried to talk him into a deeper groove for a Mav Dutchman analog, but so far, no luck. I'm going to keep working on him. I think he can do it with the wider groove, I believe he just has that depth (0.03") as his default because most all grooves are much narrower. He is worried about tool clearance and his cutting tool geometry.
Marc (Mav) gave us the original Mav Dutchman design so I know the exact the dimensions and geometry for that bullet. Below is a model of it along with the alternative I came up using Tom's requirements. Note the side walls are also much steeper on the Mav Dutchman (Tom's 35° may truly be a hard limit, but I would accept that with a deeper groove). I may post the models over on the Darksider's Den and solicit input as to interest. Tom already has a couple of potential .44 BP bullet substitutes in his catalog, So I don't know if it is worth another design unless he will deepen the groove for me.
Note the Lube volume of the original Mav Dutchman is 0.1141cm
3, but the alternative is 0.075cm
3. So, 34% more with the Mav., but the actual lube bearing surface is 12% longer (which is a "win") on the alternative. I don't know if you have ever recovered the Mav Dutchman or PRS .45 after firing, but based on the bullets I have retrieved, I believe they still have 25% to 35% of the lube still deep in the groove.
~Mako