Here's an image of the 45-70 and 460 S&W FCD's next to one another.
By all rights, they are identical.
Look down in the tops of them and you notice that the collet bites are definitely not in the same location.
Closer examination of the collet bites with a 450b case in them and you can see that a lot more of the 45-70 collet had to be removed to get the bite at or below the mouth of the 450b, as opposed to the 460 S&W which is almost there.
Looking back at the beginning of this thread, you could not remove enough of the 45-70 collet base to get the bite down to the 450b mouth without it being up inside the threaded body which would not allow it to work, so that's why we needed to remove some of the threaded body before cutting back the collet base. The collet base can be shortened to put the crimp anywhere you want within reason. Fortunately, the 460 S&W FCD bite is only about .1 inch longer than the 450b case. So if you wanted to put the crimp at the mouth you would need to remove about .1 inches. Many stab crimp members here settled for having the stab .15 inch
below the mouth, so that would involve removing another .15 inch or a total of about .25 inch from the base of the collet. An easy target for where to cut the collet base turns out to be the top of the groove where the caliber is stamped on the collet.
That will still leave enough of the collet base protruding from the body to allow it to push up into the body so the jaws will constrict and apply the bite.
It you want to be able to go lower down the 450b case to apply your stab crimp, you will need to remove some of the threaded body to allow enough collet travel to get it to engage. A worst case scenario would be removing .25 inch of the threaded body. That would allow you to shorten the collet to where you could move the stab crimp anywhere from about .35 below the mouth and up. Keep in mind that the further down the case you choose to make your stab, the thicker the wall is and the harder its going to be to get a good transfer through it. It is paramount to make make a clean cut where you remove the threaded part of the body, so that it will screw down into your press without binding. (IE not a hacksaw) Remember that in order to move the crimp up or down at will, requires using shim washers every time you crimp. I just modded several of the FCD dies at different crimp depths and swap out the one that is most appropriate for my particular reloading project to avoid the time and dummy case expense of setting them up each time I change bullets. That having been said, .1 to .15 inch below the mouth suits a lot of bullets. The hardest part to get right is narrowing the bite enough to transfer through the brass wall to the inside of the case and down into the bullet without turning your die into a tubing cutter. Sad fact of life is the narrower the better.
I once did an experiment using the original wide bit width to see if just having more contact area would equal the retention of one sharp narrow bite. It didn't. The 450b does have its peculiarities.
As several members have noted, it you want a wide range of adjustability on your stab crimp placement, then go with the 45 LC FCD. Its already shortened. You just need to make up a lot of shim washers and go through the adjustment setup when you change bullets.
Lest I forget,
Midway has the Lee FCD's on sale for $12.59 as I write this. Now that its no longer a custom order, the 450b one will ultimately be the best choice for stab crimp modding.
I still offer to mod a Lee FCD for members who don't have easy access to machinery. All you need do is
order 2 of them and have them shipped directly to me. I'll mod one and send it back to you per your specifications, The other one I keep to cover the cost of Priority Mail postage and a little something for my time. How did you think I could afford making so many different fixed length stab crimp dies for myself?
PM me if interested.
Hoot