Answer this please, can this roll crimp?

Pond said:
Would it not be better to turn the die in that half-turn, whilst holding the bullet seating adjuster immobile?
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If the pitch of the threads are equal, yes, exactly correct.

If you are not sure the thread pitches are identical, pulling the seating stem further out than necessary (or completely out) produces exactly the same (desired) result-no bullet movement during the crimping process.

Lost Sheep
 
If you are not sure the thread pitches are identical, pulling the seating stem further out than necessary (or completely out) produces exactly the same (desired) result-no bullet movement during the crimping process.
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So seat the bullets first, then pass the cartridges through the same die a second time but this time for crimp?
 
They then turn the whole die half a turn more for a half-turn of crimp, but does this mean that the bullet would then also be seated that half turn deeper in the case?
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No.

It is not seated any deeper in the case. You are not changing the distance between the steating stem and the crimping shoulder in the die. What you are changing (by screwing the entire die assy down) is the distance relationship between the crimp shoulder and the case mouth.
 
You are not changing the distance between the steating stem and the crimping shoulder in the die. What you are changing (by screwing the entire die assy down) is the distance relationship between the crimp shoulder and the case mouth.
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OK. Still struggling.

If we agree that, as the shell-holder retains the case and the ram moves it as high as it can go for the die to act on it, the distance between the seating stem and the shell-holder dictates the OAL.

As I see it that distance cannot remain the same if the entire die body is screwed in another half-turn. The seating stem has to move closer to the shell-holder because it is part of the die.

This is what I can't get my head around. Despite two potent coffees.
 
OK. Still struggling.

If we agree that, as the shell-holder retains the case and the ram moves it as high as it can go for the die to act on it, the distance between the seating stem and the shell-holder dictates the OAL.

As I see it that distance cannot remain the same if the entire die body is screwed in another half-turn. The seating stem has to move closer to the shell-holder because it is part of the die.

This is what I can't get my head around. Despite two potent coffees.
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It will decrease the OAL, how could it not. It should decrease the OAL by .036".

You are bring the entire die closer to the shell plate and the press strokes the same every time. Those dies are 14 thread to an inch. 1/14 is .072/2 for half a turn.
 
I'm not a fan of Lee dies, and have not seen their videos, but I have 45+ years experience with what works for Lyman, RCBS, and others.

You asked if screwing then entire die assy would seat the bullet deeper in the case. I said no, because it does not, under the conditions you described.

There are other conditions where it could, but those are not what we are talking about here.

Does turning it all down a thread (or a half) shorten the OAL? yes. But the distance relationship between the end of the bullet and the case mouth remains the same. So your crimp stays in the correct place on the bullet. The OAL of the round is slightly shorter (by the amount you lowered the die body), but why do you care????

The tiny difference in OAL length is insignificant.

Here is the method that has worked for me.
Run a case all the way up to full ram extension.
Screw the die body in until it just "kisses" the case mouth (seating stem backed out)

insert the desired bullet and adjust the seating stem until the bullet is seated at the correct depth for the crimp.

Back the seating stem out a couple turns.
Screw the die body in, until you get the desired amount of crimp. Then lock it down.

Screw the seating stem down until it firmly contacts the bullet, lock it down, and you are good to go.

Load a couple rounds and examine them carefully. They should be just what you want, but if not, they will be very close and final adjustment of either the body or the stem will be small fractions of a turn.

Of course, all this assumes uniform components (bullets and case length).
 
Somebody please correct me if I'm wrong but I've always thought that it was the specific bullet profile that determines the crimp type - not what the headspace is based on.
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Yep, bullet design...
 
Does turning it all down a thread (or a half) shorten the OAL? yes. But the distance relationship between the end of the bullet and the case mouth remains the same. So your crimp stays in the correct place on the bullet. The OAL of the round is slightly shorter (by the amount you lowered the die body), but why do you care????
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I just wanted to clarify the process as I was just starting to question my intelligence.

However, I had understood correctly in that there is a change in OAL. How much is not the issue. I couldn't work out how it could be done without that change. Given the change is insignificant, then I can see why reloaders are not concerned with it.
 
while seating the bullet so it is "just off the lands" can be a factor in getting the most accuracy from some rifles, its a moot point when you are loading revolver ammo.

There is, essentially, no "too short" OAL, and the only "too long OAL" is where the bullet sticks out the front of the cylinder.
 
44 AMP said:
I do take exception with this, though...
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Not if you use one of the Star presses that push the die plate down. But I should have said the motion is relative.

Now it's "my turn, my turn, my turn", to take exception to a minor point ;):

44 AMP said:
It is not seated any deeper in the case.
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Actually it is seated deeper, just less than expected. That deepening of seating is what creates the shaving effect. I used to get so many lead rings from that on .45 Auto that it would build up in my Goldcup's chamber and either interfere with chambering or get blown loose and wind up riding or mishaping a bullet that became a flier. So, for awhile, I used a dental pick to take the rings off the finished rounds one at a time. Then I discovered separate taper crimping. This was circa 1979 or so. I think that's the year I first became an NRA Life Member, too. Got tired of remembering the annual renewals about the same time I got tired of dental picking the lead rings. TAR has followed me ever since.

But here's the reason the seating depth increase is less than the anticipated 0.036": When you are crimping you are also compressing the height of the cartridge with the crimp shoulder. This tends to cause the brass to bulge as I showed in the exaggerated illustration and to experience barrel distortion also below the bullet base position. But as long as you don't compress it hard enough to surpass the yield of the brass as that third illustration depicted had happened, then it springs back, returning some of that compressed length. The greater the case length, the more easily this happens. If you try the same experiment with a die that constrains the brass diameter more, like the Redding Profile Crimp Die (great revolver die, BTW), you will see the COL shorten more in line with the crimp adjustment.
 
The .44Magnum headspaces on the case rim, so minor variation in total length are irrelevant as a safety concern, and generally insignificant in terms of accuracy as well.
 
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