450Bushmaster.net

Greetings All,

I bought a 450 BM upper for a dedicated build. I've been reading all the posts on this forum and see a great many knowledgeable people responding.
I'm curious why there seems to be a lot of "reinventing the wheel" in progress.
Why, instead of modifying a LEE FCD one wouldn't have LEE make a custom FCD and limit the max crimp to.476?
Wouldn't a cannelure tool for uncannelured bullets also be helpful?
Seems to me that with these two tools, you could solve some if not most of the issues involved with reloading this cartridge.
My reason for asking is the build is underway and I've bought my share of stuff over the years backwards (and backwoods ) engineering to know you can waste a lot of cash making due when you could cry once and spend once to get where you want to go.

Welcome to our campfire! As a matter of fact we do have a couple of guys with cannelure tools who have been testing. As for the crimp die, the LeGendre Side crimp die is a whole different animal.

I'm new to this cartridge, could you explain the advantage of the side crimp over the usual method of crimping a cartridge that head-spaces on the case mouth?

boolitschuuter wrote:I'm new to this cartridge, could you explain the advantage of the side crimp over the usual method of crimping a cartridge that head-spaces on the case mouth?

boolitshuuter-
I'll try to explain, and let the pros fill in the gaps or correct as needed.

The 450B cartridges headspace on the case mouth, as you note. In general, the appropriate crimp for such cartridges is the taper crimp, which does not alter the distance between the case head and mouth. Usually the taper crimp as applied by the Hornady die is adequate for most bullets and loads.

For some combinations of powder and bullets, particularly for powders that are "slow" for this cartridge, and for bullets that are light weight or smaller than .452 in diameter, there is a problem with developing enough pressure initially to get the powder to ignite and burn adequately. In such instances, methods of retarding the exit of the bullet from the case, i.e. increasing the pull, can allow adequate pressure to develop in the chamber. The difficulty is determining how to increase the pull.

A roll crimp won't work, because it disturbs the headspace. Applying a case sealant between the bullet and case has been discussed in this forum, and tried by a few; it hasn't been very successful. Applying a cannelure and taper crimping into it is a possibility that's currently being explored as a way of increasing pull. Applying lots of taper crimp, which can be done with the Hornady die, really distorts the bullet and decreases accuracy.

The side-crimp is another method that has a fairly long history. The use of a modified Lee 45-70 collet-type Factory Crimp Die was explored early, and appears to be at least partially successful. The modifications involve a shortened stem, and a thinning of the crimping ridge; these and other mods are described well in some stickies in the forum titled "Reloading the 450B".

The reason for not asking Lee to produce a modified FCD is the expense involved. I haven't priced a custom die recently, but when I did the cost was significantly more than the cost of the time for machining the 45-70 die. For my own die, it didn't take much time to do the conversion on a small home lathe. For the side crimp, one wants the squeeze to be more than the .476" attained with the Hornady taper crimp die. With appropriate spacers between the shell holder and the die stem, the crimp can be placed exactly where it's needed on the side of the cartridge. Combining the side crimp with a cannelure custom-applied to a bullet is being worked on. Again, the problem for some of us is the expense of a decent cannelure applicator. My half-baked attempt a couple of years ago was not worth noting on the forum.

If this leave unanswered questions, please post them.

Welcome to the forum.
--Bob

If you haven't already done so, read This Thread at least as far as the sequel. It will lend images to pitted bore's excellent advice.

Hoot

Thanks guys, excellent explanation. Cleared up some questions I hadn't even thought to ask yet.