Alpha Dasher brass case lip "oversized"?

[918v]

This is normal. That what a case mouth looks like after you run it through a bushing sizer or any standard sizer. I prevent it by sizing the neck with a Lee collet neck die and a Redding body die. The problem nowadays is Lee redesigned the collet neck die to intentionally produce that very same flare. When I pointed it out to them whoever is in charge now told me it was done to make bullet seating easier and a crimp die would take care of it after. Fortunately I have an older variant that doesn’t do that.

A mandrel removes most of that flare by expanding the neck but still leaves a little at the case mouth. Sometimes this causes chambering issues in tight neck chambers.

 

[Huskydriver]

@Senor_Barney you figure this out yet?

 

[Senor_Barney]

@Huskydriver

Not with certainty.

My best guess at this point (it is just a guess until I get back to the non-existent lab in my basement) is that

a) Perhaps the clamp nut was too tight on the bushing and it couldn't self center when sizing a case. So the case was going in all cattywampus. I've since reset my die just to be sure .

b) This is a normal part of the bushing die sizing process...and 4-5 out of every 100 cases will have this flare happen. I am about to size 205 rounds this afternoon.

I'm planning to resize 205 Lapua 6 creed cases this afternoon and will monitor the sit.

 

[Cascade Hemi]

I have found that bushing dies are more sensitive to how much they will size down in a single operation. I've sized down .294 to .276 in a single pass with non bushing dies without flaring but had to use an intermediate step with as much as .010" with bushing dies. If I'm reading your original post correctly, it appears you're sizing down .007" using Whidden bushings and then sizing up .005" with a mandrel. That is probably the issue but it's just a guess without knowing the actual size of the bushing (bushing sizes need to be verified with pin gages). My goal would be .002" under your mandrel diameter with annealed brass. Harder brass has less consistency and more spring-back in both directions of the sizing. New brass has pretty inconsistent hardness too, even Alpha.

What is the diameter of the loaded case necks? Do you have a tube mic and/or a standard mic? It would be helpful to mic the brass necks, the mandrel, and gage the bushing.

 

[918v]

Maybe there is a difference in neck hardness between the ones that are flared and the ones that aren’t.

 

[Cascade Hemi]

Maybe there is a difference in neck hardness between the ones that are flared and the ones that aren’t.

Could be. There is a lot of missing information.

 

[dnchrist]

1. dry tumble 20-30min to get the lube off
- don’t wet tumble to remove lube
- what will happen is your tumbler and pins will get coated in lube, and you’ll have to deep clean them

2. trim and chamfer

I use Lyman in an ultrasonic instead of tumbling to remove lube. I don't have to worry about junk in the primer pockets or inside the case.

 

[Lawnboi]

Try a SAC bushing in the die.

Make sure the interior is lubed well enough when you use the mandrel.

 

[BuildingConceptsllc]

Just curious for anyone who knows. As @spife7980 said, the bushing is supposed to go writing side down, and it has a chamfer in it so that it receives the case evenly just like when we do our cases to receive a bullet. (It also requires a spacer for the redding, which I forgot about last night and spife once again helped me as he has before)

Question is this. All of my redding bushings have chamfers on both sides, and they appear to be equal in every way. The only difference in either side is the cut out notch that goes around the outside of the bushing is closer to one side than the other, but I can't see any difference as far as inside the bushing. Just curious and I thought it fit in this thread but I don't want to mess the op up so if I need to move it just say so OP and I will gladly do that.

 

[Huskydriver]

@Huskydriver

Not with certainty.

My best guess at this point (it is just a guess until I get back to the non-existent lab in my basement) is that

a) Perhaps the clamp nut was too tight on the bushing and it couldn't self center when sizing a case. So the case was going in all cattywampus. I've since reset my die just to be sure .

b) This is a normal part of the bushing die sizing process...and 4-5 out of every 100 cases will have this flare happen. I am about to size 205 rounds this afternoon.

I'm planning to resize 205 Lapua 6 creed cases this afternoon and will monitor the sit.

Anything?

 

[howler]

Try a SAC bushing in the die.

Make sure the interior is lubed well enough when you use the mandrel.

Neck is too short, you don’t get enough bearing surface with SAC bushings on dasher brass due to the super long taper SAC uses. They don’t use that taper design for this specific reason on their actual dasher dies.