Texas Sheepdawg wrote:So this Le Gendre side crimp... Is that a die used to
Modify the crimp on a factory crimp? I find this data
Interesting because I have a 20" . Could you elaborate
On just exactly what is being done here? I do plan to
Reload my own and the results described here have me
Very interested in learning the details of what this side crimp
Process is, how it's done, and if this is a die, is it available?
The LeGendre Side Crimp (LCS) is a method of bettering the Thermal Dynamics of the powder burn (within the case) in our or any other cartridge (some folks are now using the LCS on 458 Winchester Mags, 45-70's, 44 Mags, and many other rimmed cases, just so they don't have too trim-to-length). To better understand it one needs to review the other two styles of crimps.
There are now three styles of crimps handloaders use. One, is the Roll Crimp (RC), which before the advent of the LSC, was thought to be the best and one we can't use. The RC is used on rimmed or belted cases, for the most part. Two, is the Taper Crimp (TC), which has always been reserved for straight cases, that Head Spaces on the case mouth, like ours does or the 45ACP, 9MM Parabellum, 50 Beowulf, or any rimless case that, as I said, Head Spaces on the Case Mouth. The third Crimp being the LeGendre Side Crimp, named after that most wonderful of people, who is a Brad Pitt look-a-like, that women fawn after, that men are jealous of, that all children want to emulate, leaps tall buildings in a single bound, and has out-run Charging Grizzles (The report that the Griz was slipping and sliding in Human Feces, is a lie and doesn't mean anything and did I miss anything other accolades?) But I digress..
All three crimps have their uses and foibles. Such as, using the RC, the cases must all be the same length or the case will bulge (Which wont allow chambering) or collapse if too much RC is put on them. The TC, can have bullet pull problems (the nano-second hesitation before the case releases the bullet), resulting in tons of sooting down the side of the case, from inefficient powder burn and if bad enough, can actually collapse the case, from the side, in the chamber. This is the result, usually, of using powders of an excessively slow burn rate. Also, if the TC is not properly applied, one can experience bullet drift, in the case, which can cause an increase or decrease in pressures and their associated problems and or a Magazine Jam, if the drift increases in OAL enough. But don't let these problems stop you from using it, it's the crimp that all the Manufactures use on rimless, straight cases and we here all use it too, with great success. But the Manufacturers have displayed a keen interest in the LC, because it cures a plethora of ills. Which brings us to the subject of your inquiry. The LeGendre Side Crimp (LC).
The LC is simply a Lee Factory Crimp, placed somewhat south of the case mouth (far enough back so-as not to interfere with the Head Spacing function of the case mouth). The Lee Factory Crimp is at the exact end of the intended case, on the case mouth, right where one could find a RC. Using the LSC, maximizes powder burn Thermal Efficiency, sometimes to the point wherein, slower burn-rate powders can be used, which will, usually, lower pressures, there by, allowing you to use more of that particular, in an effort to bring the pressures back up to normal, which usually, dramatically increase the bullet speeds. However, a new reloader would not and should not experiment in this fashion, choosing more traditional, proven, safe load choices and then use a TC instead of a LSC, just to gain experience in the traditional methods of reloading. A New Reloader would only use the LSC,with traditional proven safe loads, as a method to stop bullet drift, until which time the reloaders experience has risen to the point where experimentation "Could" make sense. Keep in mind, that for the most part, the guys using the LSC, are serious experts and some of the best we have here, for reasons/needs of their own, have rejected the LSC for the more traditional Taper crimp.
I can't remember everything so some of you guys will have to chime in here and express your thoughts. There are even post you can access here, that will show you pictures and even videos of how to modify a Lee Factory Crimp Die.
But, in closing, I can tell you this, for my needs, I only use the LCS and have gone to using two of them now, both on the same case. I hope this helps, but keep in the front of your mind, that using a Loading Manual is the safest way to learn the Basics and the LSC is not a Basic and just like Slicks on a race car can be very helpful, using Slicks can break a differential, so go slow and go safely, only after you truly understand the physics should you move on too other choices, like The LeGendre Side Crimp..t