Hello, gentlemen. I thought I would tap your expertise again to help me resolve an issue of current concern(probably the proverbial "making a mountain out of a molehill", but please bear with me a bit).

I just bought a new batch of Starline .44mag. brass and am working up a heavy load with an extruded powder. Consequently I'm finding out the importance of a really tight crimp -a few rounds with inadequate crimp left a good bit of partially unburned powder in their wake. BUT, the sharp edges on the case mouths, which seem to ensure a good crimp by biting into the cannelure, are a problem in the expander die. They scrape the outer wall of the expander and get roughed up a bit(I also wonder if they're scratching the expander.). Chamfering of course alleviates the problem, but does it make the crimp less effective(by beveling off the edge which grips the cannelure)??

Maybe I'm guilty here of the 'reloading wierdness' mentioned in a previous thread, but sometimes I don't know whether something is important or not -unless I ask.

Also, is a little unburned powder considered normal/unavoidable with a load like this?

Thanks for all your helpful input(and patience!).

A little chamfer goes a long way...it should cause you no problems. If you feel you need a tighter crimp, just lower your crimping die a tad...

The sized case body its self probably has as much grip or more on the bullet as you get from the crimp. I feel the crimp is more to keep the bullet from moving out during recoil than any help with ignition. The crimp can be over done and acually loosen the cases grip on the bullet. Keep in mind when you tighten the crimp to watch that you don`t bulge the case behind it. I lightly chamfer my 44 mags and with a even roll crimp, not a taper, I`ve never had a problem with ignition or bullet movement.

btw I use H110 with std primers and find about the same amount of unburnt powder as I do with mag primers. Some slow pistol powders are noted as being quite dirty in this respect. I gave up on 2400 in a 357 because of this.

After many years of religiously chamfering and deburring pistol cases, I gave up. First is that the inherent unevenness of the operations leaves small marks on the chamfer, and these can easily become stress risers where brass eventually splits. You just cannot do those operations nicely and evenly.

I also am a subscriber to the idea that full thickness case mouths produce a tighter crimp. Not by much, and I wouldn't want to overstate the case, but the effect is there.

As it is now, I only trim my cases to square the mouths and then allow the burrs, both inside and out, to be knocked off during the sizing and inside expanding operations. The scraping of the brass against the die does absolutely no harm to anything. I typically use the Redding Profile Crimp die (Pro Crimp) to finish the crimp on many cartridges. The Redding die will close a crimp so tightly that the little cannelure marks of the bullets cut indents in the inside of the case mouths. Best to use on calibers like .454 Casull and others loaded with H110, etc.

Many experiments on my part, most of which are too long to tell of here, have convinced me that a really good crimp (evenly applied, no bulges, nice and square, etc.) does absolutely no harm and in a number of cases increases precision (read: shrinks groups) many times. Lousy crimps are another matter entirely.

It is apparent that crimps improve powder ignition and burning. I also use the Lee Factory crimp die for some more modest calibers like .45 Colt. It will apply a nice, even crimp all around and that has served me well, especially with the carbide ring as a size check backing the case out of the die.

Have fun, learn lots, pass it on.

There are two things to consider . The crimp is important but can be overdone which can effect accuracy. What is equally important is the grip on the bullet ,it has to be tight. That may mean a different expander.A tight crimp and tight bullet fit will insure consistant and thorugh burning of the powders especially the slow burning types.