tkknc wrote:That's why I like this board, I learn something every time I visit. Here is a picture of my reloads using the midway 2nd's. I used a taper crimp. Should I have seated them deeper?
450.JPG
In at least five, possibly more threads, I've said you need to seat the cannelure just barely out of sight below the mouth and drive the taper crimp into it. That way, you get more than just simple surface friction providing neck tension. You get the case stepped down into the cannelure and that step provides significantly greater resistance to allowing the bullet to move forward than simple friction. The heavier the bullet, the harder it is to get moving and that allows slower, harder to light powders more time to get really going before the pressure drops dramatically. In the absence of weight, friction or a case stepped down into a cannelure or driving band groove will have to do. You can go much more narrow at the mouth than most reloading resources recommend. Historically, we stopped at .478, then we went down to .476, then .475. In the latter cases you just about have to be into a cannelure or groove. Either that, or you'll be squeezing the case walls thinner or deforming the jacket of the bullet.
Let me pause here to emphasize that all this anecdotal information is as it has related to my experience with the 450b. 2400 is an excellent powder, but it is a double edged sword. It lights off easily and rises to pressure quickly, compared to other powders we use in the 450b. That reduces the emphasis on bullet weight being needed to resist moving, or it's substitute, friction, but the resulting pressure stacks up quickly when you go past the sweet spot. My experience with it has been one of a narrow window of opportunity. One of the hardest aspects in lighter bullets in this caliber is that most means to resist bullet movement add complexity to the load and can be difficult to reproduce to the exact same degree from one loading to the next, or from one bullet style to the next. It is a delicate balancing act. I believe my experiment with the deep stab crimp into the driving band groove on the Barnes 200gr XPB is probably the first time I can honestly say I was able to achieve what was IMHO, too much resistance. Had I crimped less deep, or used a narrower crimp, it might have provided a more positive experience. Maybe not. Everyone has different experiences with what they perceive to be the same crimp as they saw someone else employ. I know I've had occasions where I tried duplicating someone else' effort and had the results turn out different. Usually not as good as they claimed they experienced. Just my luck I guess.
Getting a shortened .45-70 Lee Factory Crimp die adjusted for a stab crimp it more art than science. That's why IMHO, it's hard to share or duplicate other folks efforts. It's like leveling a table with a leg that is too short by trying to remove a little length from the other legs. A lot of cut-and-try technique there and when you finally get it so it imparts the right depth of crimp at the right spot, you either knock down the setup when you're done, or you change bullets. I maintain that the process of changing it's depth in the press and adding or removing shimming washers to achieve the right combination necessary to do the job is nigh impossible to find exactly the same week or months later. If you set it up to do the same bullet at the same depth every subsequent try, you're just fine, but who wants to buy a handful of them to have set up for each unique loading you may use them for. That's why after having tried using one successfully and I might mention that I have two actually. One cut shorter to allow varying the crimp point up and down the case for many different bullets along with 6 or 7 shim washers and one cut to crimp right at the case mouth in place of the taper crimp, which I might also add, is the way that Lee intended them to be used. That why they sit in a drawer most of the time.
Too many damned variables in the equation. I'd rather compromise the bullet weight, style and/or powder type and just use the taper crimp. I'm not alone on this belief. Other members have come to the same conclusion. Lastly, despite some influential member's opinions, my experience has been that using a side crimp, especially a severe one, causes a significant loss of
repeatable accuracy. My most
repeatably accurate loads are achieved using a taper crimp. Emphasis on
repeatability. IE you being able to achieve the same results I got in a safe fashion. Heck I've produced some god awful reload recipes that still managed to yield a couple of good three shot groups among many poor ones. I'm sure there are times when everyone has to just face the fact that what seemed like a good idea, turned out not being so. Hopefully it's also educational because we can all agree that experience, while being the best teacher, is also the most expensive. I've spent more on reloading supplies since Igot my 450b last year, than in the previous 10 years of reloading and I'm not just making that up. Ask my wife. She takes great satisfaction in bringing that up every time I chide her for spending money on something I can't relate to as having a shred of worth.
Still, this caliber is full of surprises around every reloading corner. Those are more often than not, pleasant surprises. I encourage all of you to get in the mix and try different techniques and recipes. That's what makes it fun. That's what makes waiting for the next opportunity to go to the range seem interminably long in coming. That's what keeps 'em coming back.
Hoot