taper crimp die

[tbirdman74]

ran my first batch of 450's, some 225's and some 250's, today. and after spending the last couple of hours measuring and resetting hornady taper crimp die, was wondering if'n there ain't a better way. i have read here that most consider that .475-.476 is the apprpriate measurement for the crimp, so could we not ream out the top of the die to .475 thru to the crimp, then a feller wouldn't have to separate cases by length and reset the die for each bunch of lengths. one could set it and forget it. maybe i'm putting too much thought into it, just seems easier then what i went thru today.

[BayouBob]

Sounds logical so there must be a strong argument against it!

[Hoot]

ran my first batch of 450's, some 225's and some 250's, today. and after spending the last couple of hours measuring and resetting hornady taper crimp die, was wondering if'n there ain't a better way. i have read here that most consider that .475-.476 is the apprpriate measurement for the crimp, so could we not ream out the top of the die to .475 thru to the crimp, then a feller wouldn't have to separate cases by length and reset the die for each bunch of lengths. one could set it and forget it. maybe i'm putting too much thought into it, just seems easier then what i went thru today.

There is a problem with your reasoning and I'll try to explain it as best I can.

This image is exagerated on purpose to ease grasping the concept.



The current taper crimp die design relies upon you stopping your ram travel into it at some point that imparts the desired taper in the end of the brass case and it winds up also being applied to part of the softer bullet inside that case.

If you were to bore out the taper at some prescribed limit and press the case up into the limit zone, you'd wind up creating a bottle neck case and bullet.

The good news is that cases generally stop shrinking down from their spec 1.695 at around 1.675 as a worst case. That's generally speaking, but there are extreme exceptions. That's a total loss of length of 20 thousandths of an inch. That's less than the thickness of the two business cards I just mic'd, IE miniscule in size compared to the length that the taper crimp is imposed down the case, which is probably 100 thousands or more. These heavy, wide, slow by centerfire rifle standards, bullets are pretty forgiving at the performance level for variations at the cartridge dimention level. So, I'd say that while it is good practice to set your taper amount based upon the longest case you have, the resulting difference in the shortest case may not manifest much at the target board. I prep my brass and bullets more than most 450b shooters to minimize performance variation attirbutable to dimensional shortcomings or surface discontinuities when I'm doing load testing. Not just velocity variation, not just pressure sign variation and not just accuracy variation, but a balancing act between all three. From my experience, those case and bullet variations generally don't have a large influence upon performance. IE very forgiving.

I would not sweat the difference. If it troubles you, you can always trim all your cases after resizing, near the middle of the average of all of them. That will cut your variation in half right there. Then you're down to just the thickness of one business card. If you have one or two fluke cases that are way shorter than the rest, then cull them out. That's what serious accuracy fans do after weighing their cases, checking their concentricity, checking neck thickness, etc. Their calibers and bullets are far less forgiving than the 450b though.

Hoot

[wildcatter]

Well, that's kind of the crux of it all. I usually measure all of the cases and trim to the shortest one, but as this case seems to get shorter, with use, trimming, to the shortest case, isn't such a good idea.

Maybe, a mind change is in order, consider.

So much detail into a non-match gun might be part of the culprit. Again, measuring all of your cases and crimping the longest one to your minimum standard, could be part of the cure. This way all of the other cases will have some number less than the shortest one. If when you set this up, for the longest case, then crimp the shortest case and see if you can live with that number. The idea here, is that you come up with a crimp, that does all of your cases, without so much fiddling around. Let's say you crimp the longest to .474 and the shortest is .476, you now have crimped all of your cases to .475" +- .001, which is very good, wouldn't you say. And I wager, than your accuracy won't suffer any real amount.

Of course, if a bench rest 450b is what you're after, then you'll go down the road of the "Bench Rest Shooters", nightmare path. Which is the Path you're trying to go down and it might not be necessary. You've got to ask yourself, what am I willing to endure, "Great Taste or Less Filling? In our case it might better to ask, is 1.5MOA ok, or if I get real anal, I could have 1.25MOA! When I'm trying to kill targets that are 18 plus inches across.

I'm suggesting Comprises'. In other words, if a labor of love is what you want, then you can have it, if you wanna..

..t

[tbirdman74]

thanks guys, that pretty much answers my question, and the next one, "how much does it matter?" well, nuff said. hoot, your dimension of .100" of total taper crimp, do you mean that as in starting at the rim and going down the case .100"? the die i have, if i set it to put .476 on a case that's 1.695, a case that's 1.684 just barely comes in contact with the taper in the die. is it possible that we have dies with a different taper cut in them? i'm not looking for a magic cure, curiosity has just gotten the best of me.

[LlindeX]

Hoot,

I've been lurking on here for the last few months trying to learn all I can about the 450B before I began attempts to reload for it. I've been reloading for my bolt action hunting rifles for over 30 years and for my 45 ACP and 45 Colt for about 5. However, I had never reloaded for a semi-auto rifle before I got my 450B. Your explaination above makes sense. However, I don't exactly know what harm it would do to (as you say) slightly "bottleneck the case" for a short distance.

For example:

As you know, If I run once fired 450B brass thru my Hornady decapping/sizing die, it does a good job of sizing to properly fit the .452 FTX type bullets. However, the .451 sizes are too loose. I bought myself the Lee 45-70 Factory Crimp die. But haven't yet found anyone to make the mods to it yet, so using the side crimp was out of the question.

I then noticed that I could use my 45 Colt sizing die to just resize a small portion of the neck of the "previously re-sized" 450B brass. Since the Hornady 450B brass wall thickness is 0.001-0.0015" thicker than the 45Colt brass, doing this takes the diameter down to fit the Hornady .451 FMJ bullets nice and tight. With the Hornady 230gr. FMJ bullets, I "resized the neck" down with the 45 Colt sizer for a distance of 0.205", inserted my primers and powder, then set my COL at 2.105" when seating the 230gr FMJ with the 450B seating die. After seating, I have an outside diameter of 0.476" the full length of the bullet insertion into the case. I then just barely touch the cartridge with the Hornady Taper crimp die and form a 0.475" taper crimp. Causes me to have one extra step in the loading process, but that would be true with the side-crimp as well. Since I've already worked my way up to 38gr Lil Gun with 250gr FTX loads, I loaded six of these 230gr FMJ's up with the same 38gr Lil Gun and WSR primers. All six finished cartridges thunked nicely when dropped into the chamber. I tested bullet pull and it took seven good heavy strikes on concrete floor to get an FMJ to move 0.015".

Admittedly, I've only shot this load for one group of five. But my group size with the five FMJ's was slightly less than 1.5" at 100yrds. (Only slightly bigger than what I've been getting with my 250gr FTX re-loads). Also, Sooting was only slightly heavier with the FMJ's than what I've been getting with the FTX's, firing ironed out the miniature "bottleneckks", and I see no obvious signs of pressure issues. Do you (or anyone else) see any obvious problems or hazards with this approach??? I was just about to load-up fifty of these when I saw your post. Any insights anyone has will be appreciated.

[Hoot]

LlindeX, If I grasp what you're saying correctly, you are doing what a lot of bolt action reloaders do in Adding a little extra constriction to the area of the brass whithin which the bullet will be seated before seating the bullet, to achieve a little extra neck tension? That makes perfect sense to me as long as, as you noted already, the resultant mouth OD is not too small to thunk. That's just like using a smaller bushing in a bottleneck caliber resizing die, to achieve the desired neck tension for your given chamber.

That is an excellent idea! Quite honestly, despite doing that with bottleneck cases, it never occurred to me to try that with a straight walled case. My ignorance of straight walled rifle cases is showing as the 450B is the only one I've ever loaded for and a lot was learn-as-you-go. I do the 9mm, 45 ACP, 380, etc, pistol calibers, but never had a problem obtaining sufficient neck tension using the standard resizing dies that came with those sets.

It is an excellent opportunity for another area of experimentation in this caliber. I really like the idea of pre-tensioning before seating as opposed to creative crimping techniques afterward, as long as I can still start the bullet with my seating die without shaving jacket. The only thing worthy of keeping an eye on would be that the harder brass case is actually stretching to allow the bullet entry and not squeezing the softer copper bullet down as it goes in. That already happens a little using the standard 450b resizing die. I've got a box of bullets I've pulled out of loads I've made due to canceling an experiment, and you can visually see a little narrowing of the bullet where is was set into the case. I try to reuse them for fouling shots. That varies a lot, depending upon the jacket thickness and whether its a cup and core bullet or solid copper of course.

Definitely worthy of further investigation...

Anyone else on this?

Hoot

[LlindeX]

Hoot,

Thanks for getting back on this issue quickly. I went down and reloaded another 20 rounds using that technique as soon as I read your reply.

Your comment about reducing the bullet diameter during seating describes exactly why I'm now using my 45 Colt sizing die. My initial attempt was to use my 45 ACP die because it was designed for the .451 bullets. Only thing is, it sizes to the .451 internal diameter with a 45 ACP case having a wall thickness much thinner than the walls of our Hornady 450B brass. Thus when I re-sized the necks using the 45 ACP die on the 450B brass, the internal diameter became too small to properly accept the .451 bullet. Thus I checked the diameter of my 45 Colt sizing die. Low & behold, it is just enough larger to do the job correctly on the 450B brass. After I've resized the 450B neck with it, the internal size of the neck is just right, and the Hornady 230gr FMJs seat almost exactly like they do when I seat them in cases for my 45 ACP (approximately same feel on the press handle). Only real issue I've had is trying to judge and adjust the stroke of the press handle to repeatedly get the same length of reduced sizing on the necks. Hopefully, I'll come up with something which will limit the length of the press stroke so that I get the same length of "Neck reduction" every time. (Right now, sometimes I'm getting a few thousanths variation in that). I don't want to go too far down the case and reduce case capacity. But I do want to go to the bottom of my bullet's seating depth everytime, so that I get the same amount of neck tension every time. Done properly, after seating my Hornady 230gr FMJ bullet, I get an even outside case diameter of .476" all the way down the side to the bottom of the bullet and no further. If anyone has any ideas on how to "Arkansas Engineer" something to help minimize that variable, I'd be very interested.

Thanks Again Hoot! I've learned a great deal here reading about everyone's experiences and learnings. Especially your testing results, and Wildcatter's insights have been great. I don't think I'm ready just yet to push the envelope like some of the brave souls on here are, but maybe one day after I get more experience with the nuances of this caliber. I must say, amazing things are being accomplished here with it. Also, I've got to tell you all, I got my 450B because I've seen my Son take down four elk with his so far. He used to hunt them with a 300 Win Mag and I used a 30-338 Mag. With those, we were each putting 190gr BTSP's downrange a bit over 2900fps. I can definitely verify: Within the distance he's been shooting (60-180 yrds) the 450B and factory 250gr FTX's will outshine either of those. The .308 190gr's kill, but the 450B picks 'em up and lays 'em down. Nothing so far has gone more than a few yards after the shot.

[Texas Sheepdawg]

LlindeX,
Welcome to the forum! Did you get a chance to read my tests so far on the 230 Grain FMJs? By the time I moved into the 42.0 grain range with LilGun, and using the LeGendre side crimp, my sooting issues disappeared.
I'm gonna check into your method of crimping. Very interesting.

[LlindeX]

Dawg,

Yes, I've been watching your posts and your videos for a long time now. Must say, you've really taught that sheet of plate steel who's boss! The power of this rifle never ceases to amaze me. If the 'Catter can ever get the proof together to expand the accepted safety margins, this thing will be unstoppable. 2,800 - 3,000fps with a 230gr FMJ out of an AR-15!!!! And a bullet that expands to 3/4" size after going thru a telephone pole!!! Gosh, what will they think of next? a 450LM on an AR-10 frame?

I plan on working my way up some with my powder weight on these 230gr FMJ's. I don't have a chrono, and since I'd never tried necking straight wall cases down like this, I wanted to really play it safe. I figured if I knew that 38gr Lil' Gun & 250gr FTX's was looking fine in my chamber, then I'd start with the same powder weight with the 230's to be safe. However, I must say, I was impressed with the group I got with the first small amount of testing. From what I've read on here, I didn't expect the FMJ's to shoot anywhere near as good as the FTX's. Who knows, maybe I was just lucky on that single first group, & it'll never happen again????? Let me know how it goes with your testing of this loading method.