Notes about the Lee .45 Taper Crimp Die

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Notes about the Lee .45 Taper Crimp Die

Postby pitted bore » Sun Jan 16, 2011 8:30 pm

In this forum, questions have been asked about the Lee .45 Taper Crimp die: Would it work
for loading the 450B? Does it differ from the Hornady taper crimp die that comes with the
450 Bushmaster die set? In October 2010 I wrote that I would try to compare the two dies.

Short answer: The Lee die and the Hornady dies produce different taper crimps, and operate
differently.

The die is Lee #90785. I've attached a photo of it below, taken from the midwayusa.com
web site (where I ordered mine). It's a 1-piece die like the Hornady die. Lee says
it is suited for the 45 aCP, 45 Auto Rim, 45 Schofield, 455 Webley Mark II, and the 45
Win Mag.

I used this die and the Hornady die in trials, crimping Sierra #8830 300-grain jacketed soft flat
point "sportsmaster" bullets, nominally .4515 dia, into new unfired Hornady cases. When I measured
the bullets, they were 0.4505 diameter uniformly from the crimp to the base. The bullet base was
0.4510 diameter. (All measurements are in inches; apologies to the metrically inclined.)

With the bullet seated to the crimp groove, the outside diameter of the case at the mouth was
about 0.478. The Lee die crimped the case to 0.4760 dia. as far down the case as the die could
be pushed. The measurements were uniform along the length of the bullet in the case.

Pulling the bullet took a half-dozen raps with my "kinetic puller". The bullet did not seem
deformed by the crimping, and was the same 0.4505 diameter from base to crimp groove.

The Hornady crimp die acts differently. If the same bullet is loading in in a new case and
run up into the Hornady crimp die, mouth diameter of the loaded round will vary depending
on how far it's run into the die. Starting at 0.478, further insertion decreases mouth
diameter. If run into the die as far as the shell holder permits, mouth diameter can be
0.456 inhes .

This is a whole lotta crimp. It's well under SAAMI minimum mouth diameter for the
450B, and it distorts the bullet considerably.

So, the Lee die applies a uniform, firm crimp, the full length of the bullet. The Hornady
die can apply a variable crimp.

At least for a while, I expect to use the Lee die routinely. If something comes up to
change this, I'll come back to this thread.

A couple of notes on Lee #90785:

It's not a collet crimping die like the 45-70 die (Lee #90856) that can be modified for
applying a 450B side crimp.

It differs also from Lee die #90786 for the 45 Colt/454 Casull. Lee describes it as a
"taper" crimp die. #90786 is really a roll crimp die, according to information
Wildcatter received from Lee (link below).

The initial thread that introduced the Lee die question in April 2010:
http://450bushmaster.net/viewtopic.php?f=5&t=600
This is the thread with Wildcatter's report of his conversation with Lee.

Some further discussion of the problem from October 2010:
http://450bushmaster.net/viewtopic.php?f=5&t=746

I don't know how Lee #90785 differs from the Lee Carbide Crimp die for the 45 ACP, #90864.

--Bob
Attachments
90785_L.jpg
The 45 ACP Lee Taper Crimp Die
90785_L.jpg (13.86 KiB) Viewed 9750 times
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Re: Notes about the Lee .45 Taper Crimp Die

Postby BayouBob » Sun Jan 16, 2011 9:46 pm

Bob, Thanks for the tests. Did you conclude that the Lee die put a firmer grip on the bullet because of the uniform crimp than the Hornady with it's varying depth crimp?
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Re: Notes about the Lee .45 Taper Crimp Die

Postby Hoot » Sun Jan 16, 2011 11:40 pm

If I'm not mistaken, the 450b case wall gets thicker as you go down the case. Wouldn't crimping the outside of the case to the same diameter down the length of the bullet actually cause the bullet to be squeezed more near its base due to the wall being thicker there? Somewhere in this forum is a side view of the case wall with the measured thickness, but I don't recall exactly which thread it resides in. IIRC it was a comparison between the .284 Winchester brass and the 450b brass as manufactured by Hornady.

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Re: Notes about the Lee .45 Taper Crimp Die

Postby lucasphi20 » Sun Jan 16, 2011 11:57 pm

I guess I am confused why there are so many posts on different crimp dies. I use the Hornady crimp that came in the 450 Bushmaster die set. I crimp it to .476 and my rounds perform like factory.
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Re: Notes about the Lee .45 Taper Crimp Die

Postby Hoot » Mon Jan 17, 2011 8:59 am

lucasphi20 wrote:I guess I am confused why there are so many posts on different crimp dies. I use the Hornady crimp that came in the 450 Bushmaster die set. I crimp it to .476 and my rounds perform like factory.


As do I, but I'm always looking for a better mousetrap. IMHO, factory loads are not necessarily the epitome of performance. Usually, they're as good as you can get for a given price point (pain point) while still maintaining the manufacturer's acceptable profit margin and lest we forget, not getting the corporation's lawyer's underwear in a knot. In the case of the Hornady 250's, they're the only factory load we can get. It's easy to excel in a field of one.

The LeGendre mod to the Lee .45/70 Factory Crimp Die, which up until now was the only other crimp in wide discussion here, sought to address the need for more neck tension when using other bullets that benefit more from a stab crimp than a taper crimp. If I can get more, consistent neck tension from a different taper crimp die without damaging the bullet, I'll order one today.

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Re: Notes about the Lee .45 Taper Crimp Die

Postby BD1 » Mon Jan 17, 2011 11:51 am

Note: none of the following has much real value in the everyday world of hunting for most folks, but if you're a gun crank like me, read on:

My primary interest in using a modified Lee 45/70 crimp die was to eliminate bullet jump on chambering. When I started into loading for the .450B I was using the 250 grain FTX and Hornady factory new brass. While I had excellent accuracy at 100 yards, the velocity deviation across the chrony was about 4 times what I like to see in a rifle load, so I started looking for reasons why. What I discovered was that my bullets were jumping forward slightly upon chambering, and not in a perfectly uniform fashion. As I started to try cast lead boolits in my .450 this issue became more significant. I could not eliminate this jump by adjusting the Hornady crimp die, so I modified a Lee 45/70FCD to address the issue and that brought the velocity variations down to acceptable levels.

I've been at this a couple of years now, and I've learned a few things. Last summer I bought a couple of boxes of factory ammo, (the first I had ever seen), and I shot up a box for reference. The factory stuff is a tad bit slower than what I handload, giving about 2,100 fps out of my 16" barrel. At 100 yards the factory stuff stays in one ragged hole, but as I shoot farther out my handloads start to shine a little brighter. At 300 yards the factory stuff is grouping between 6 and 8 inches, with occasional shots quite low, while my handloads consistently stay at moa. IMHO when using bullets with the low BC values that we're using in the .450s, variations in velocity play havoc with long range accuracy.

My current favorite load in the .450B is the Hornady 250 gr FTX loaded over 40 grains of WC297 in cut down .284 brass with a Federal 210 primer, COAL 2.60, average velocity 2180fps out of my 16 inch barrel. 40.5 grains shoots just as well, but the extra velocity puts it a little outside the limits of the BDC reticle on my scope so I prefer the .40 grain load.

I like the cut down .284 brass as it gives me better neck tension, requiring less body crimp, and I get more loads out of it before it shrinks below the 1.690 "trim length". Also the large rifle primer seems to provide more consistent ignition. I seat the bullets out to sammi max length as the throat in my rifle extends at least .2" beyond the chamber. I have no function issues with this load at all. The factory stuff I bought is all seated close to 2.45, for what reason, I don't know.

If I was having a custom barrel made, (and I may yet do this), I would have the chamber cut to 1.80 and no throat at all. I would then hand throat the barrel using a 1911 throating reamer until my loaded rounds just passed the thunk test. I believe this would give me even better accuracy, and I'd be able to use .284 brass cut down to 1.79 until it got shorter than 1.70 when I could sell it to you guys and buy myself a new batch :)
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Re: Notes about the Lee .45 Taper Crimp Die

Postby Hoot » Mon Jan 17, 2011 2:40 pm

Hoot wrote:...snip...Somewhere in this forum is a side view of the case wall with the measured thickness, but I don't recall exactly which thread it resides in. IIRC it was a comparison between the .284 Winchester brass and the 450b brass as manufactured by Hornady.

Hoot


Found it back a few pages. Here's the chart:

Image

If you say, seat the bullet .35 down into the case, the wall at that point would be .008 thicker. Crimping the outside of the case the same diameter down that .35 inches would squeeze the bullet .008 narrower at it base wouldn't it? It may spring back to it's original thickness once it is propelled out of the case. I don't know the elasticity of a copper jacketed bullet. Just trying to examine all the possibilities.

Once last summer, I crimped some loads using the Hornady resizing die to a mouth OD of .476, to see what if anything would happen. They flew relatively the same as when I used the Hornady taper crimp die to the same OD, so perhaps there is the answer.

BD1: Did you mean 2.260 and 2.245 not 2.60 and 2.45 COAL?

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Re: Notes about the Lee .45 Taper Crimp Die

Postby pitted bore » Tue Jan 18, 2011 12:14 am

Hoot at 12:40 am wrote:If I'm not mistaken, the 450b case wall gets thicker as you go down the case.

Hoot-

Well, yes and no.

You're absolutely correct in identifying case wall thickness as the significant factor in looking at possible distortion of the bullet caused by a taper crimp. In the instance of the type of crimp applied by the Lee die (sort of an untapered taper crimp), the case wall is going to be forced against the bullet the entire length of the bullet inside the case. If the case wall gets thicker toward the rear of the bullet, it could swage the bullet into a segment of a cone. This probably would not help accuracy.

I've spent an interesting evening measuring wall thickness with my lot of 450B Hornady new unprimed brass, using my RCBS "casemaster", and checking those measurements against my Mitutoyo tubing micrometer. The exercise has some built-in frustration, because at any selected point on the length of the case, the thickness can vary by about 0.0005". (This is actually pretty good for rifle brass.)

I found that for the first 0.5" +/- about 0.03" from the case mouth, the case wall thickness was pretty uniform at 0.0135 to 0.0140 along that whole length. From that point back toward the case head, the wall gets progressively thicker. At 1.0" from the case mouth, the wall is about 0.030" thick.

Your chart and table of measurements of internal diameter show two aspects of case shape: wall thickness, and external case taper. According to the SAAMI drawing, the external case will taper from 0.500 near the base to 0.480 at the mouth. So, even if the case had walls of uniform thickness, the ID would decrease by 0.02".

Hoot at 3:40 pm wrote:If you say, seat the bullet .35 down into the case, the wall at that point would be .008 thicker.

I think this inference of case wall thickness from the chart may be unwarranted. At least with my measurements from the mouth down to about 0.50", the case wall did not increase in thickness. A rough measurement with the inside jaw of my caliper on my cases showed about what yours did in the plot - a decrease in the inside diameter. However, this decrease was not caused by a change in case wall thickness.

(I admit I could not follow your description of a problem with your measurement technique that might have produced the plateau at about 0.5" from the mouth: 284 vs 450b Case ID Comparison.)

It is entirely possible that my measurement techniques are flawed, or my instruments are inaccurate, or my lot of 450B cases is atypical. It would be helpful if somebody would corroborate or contradict my observation that the case wall is of uniform thickness for a half-inch of length from the case mouth back..

The half-inch length permits normal seating of most bullets. The Sierra 300-grain flat points seat about 0.4" into the case, which is about the same as the 250 FTX Hornady bullet.

Thanks for your comments, which are always welcome from one who can produce such nice 450B groups.

--Bob
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Re: Notes about the Lee .45 Taper Crimp Die

Postby Hoot » Tue Jan 18, 2011 5:19 am

Aw Shucks! I used data from a thread about apples to comment on a thread about oranges. That is to say, the graphic was from a thread that sought to compare internal dimension differences between a resized 450b case and a resized, cut-down, 284 Winchester case. You're right Bob, I did not reference the IDs to their ODs in the graphic as that was not the thrust of the thread.

FWIW, I'd be more inclined to trust your measurement method than mine as I don't have access to a tubing specific micrometer. I do own a nice micrometer, but it's for flat surfaces. I still have the 450b case I used for the measurements set aside. I can do .025 incremented measurements down the outside and then plot them against the internal measurements. That would provide an outside vs inside profile. My gut feeling is that they will still show a thickening of the wall starting at the case mouth, increasing as you head towards the base. I'd be tickled pink to discover that the wall thickness stays the same for the first half inch down or so. Perhaps the measurement would be more relevant if it were performed on a case that had been fireformed to the chamber since that's the dimension we have to ultimately work with. I don't want to produce a reloaded round that departs too greatly from the inherent taper in the chamber.

Where's Tim when you need him to wade in?

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Re: Notes about the Lee .45 Taper Crimp Die

Postby BD1 » Tue Jan 18, 2011 9:59 am

BD1: Did you mean 2.260 and 2.245 not 2.60 and 2.45 COAL?

Yes, sorry for the typo.

I've sectioned a few of each of the case types and the Hornady factory cases do appear to have a uniform wall thickness near the mouth, while the .284 cases taper. I have a tubing mike, but never felt the need to quantify this further. I use the Hornady factory brass for cast bullets sized .453 and can seat everything up to 325 grains to proper OAL and it will function just fine. I use the cut down .284 brass for all of my jacketed loadings and it will handle jacketed bullets sized .452 up to the 325 grainers with no issues.

Where I run into issues is with cast boolits over 325 grains. I've dealt with that by running a .4525 reamer into fired Hornady brass which ,when resized, buys me enough clearance to seat cast boolits up to 405 grains or so with OK functioning. IMO the only need for boolits that heavy in the .450B would be subsonic loads, and the pressures involved are relatively low. It does bring up the problem of needing to segregate that brass though.

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