by Hoot » Sat Oct 11, 2014 6:01 am
IMHO, the hardest part of modding a 45-70 die for stab crimping isn't getting the length right. It's narrowing the width of the bite that the collet makes. A narrower bite provides a more assertive hold on the bullet while not disturbing the case and bullet as much as a wider one. I have many Lee FCD for other calibers that I reload. They all are made with a fairly wide bite width. I mention this because I'm not sure that having Lee make you a die, will result in them getting the bite width correct. If they can do that, then the $25 price is quite reasonable.
It would be enlightening for someone to send them a sample case with a narrow bite width and see what comes back from them. The issue for a reloader who does not have a modded die in the first place, to produce a sample case for them to use as a guide. Kind of a chicken and egg conundrum.
If you want to "go the dough", I can produce a narrow bite example for you to send them.
WRT bullets that do not have a cannelure or driving band groove, the stab crimp requires more pressure to produce a worthwhile improvement in bullet hold and it disturbs a little more of the case and bullet, but it does work. In reloading for the 450b using Hornady dies, almost everyone here who does that, does Not use the flaring die. It's not necessary with jacketed bullets and adds additional work-stress to the case mouth brass.
Edit: I forgot to address one of your questions.
Again, IMHO, tools that impart a rolled cannelure after the fact, do not produce the same result as having the factory do it. If you look at a factory cannelure, it is down into the bullet and the jacket on either side is relatively undisturbed. In the home made cannelures I've seen, some of the copper displaced by the cannelure is pushed back up out of the trench causing a ridge on either side of it. That could potentially catch on the case mouth when seating, possibly shearing off small bits that lodge between the bullet or resulting in less consistent neck tension than we already encounter. This is purely speculative as despite having seen home made cannelures, I have actually never reloaded them myself. If a tool can produce a cannelure just like the factory ones, in already manufactured bullets, without allowing the displaced material to rise up on either side, then that would be a useful tool for this caliber.
Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.