simpleman wrote:Good reading here.
A question for Hoot.
Sounds like neck tension is the key. What do you think about 3 of the modified crimp dies used on each round.
3 dies sized to crimp the mouth of the case, step next crimp just below that and one more below that with a determined measurement between crimps. This way you could do light crimps with out deforming the case or bullet and still get good neck tension.
This would only add a min to each round reloaded.
Has anyone tried this and what results did they have.
I tried two, but never three. In the case of the two, it was using the 200gr FTX trying to hit the two cannelures. Oh it gave excellent tension, but the lower cannelure was so close to the bullet heel that the crimp actually displaced the copper where it transitioned from side to heel and accuracy went down the drain. In the case of the Barnes 200 XPB, I set stab crimps into both driving band grooves, which are not there to be used as cannelures. After 15 strong smacks on the concrete floor in the shop, the bullet had not moved one bit and I gave up trying to dislodge it. in practice, I was amazed at how much velocity increase I experienced from the Lil Gun charge, but the feeling I got through the gun was one of a controlled explosion as opposed to what it normally feels like, even with stiff loads and it creeped me out. Accuracy from the three rounds I shot before aborting that experiment was average. They clocked out the barrel just over 2500 fps for a charge that normally yielded 2300 fps with just a taper crimp. That was one of the few times my spent 450b brass actually grew longer after firing it. That also creeped me out. They were factory new, all trimmed to make te as close as possible to 1.695 and while they normally wind up 1.680-685 after the first firing, those three were IIRC 1.702-1.705 after resizing.
Anyway, my recommendation would be to mod up one .45-70 FCD and make a run of 3-stab loads using shims, to try before buying and modding two more dies to commit to the process. That way, if it winds up being an interesting idea that didn't pan out, you're not out so much dough. I've had a few of them, so I know.
Though I bemoan the process of setting up the shims as tedious and hard to precisely replicate, it can be done, given enough attention to detail. If you have already modded an FCD or intend to, I'd say give it a try and give us a report. Something else worthy of trying on the way to modding one would be to leave the collet jaws full width long enough to load up some already known loads, but instead of using the taper crimp, use the FCD in the capacity that Lee intended it to be used on some. I often wondered how it would perform when used that way as opposed to a narrower stab crimp further away from the mouth.
Hoot