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6 Dasher False Shoulder Setting Technique?

Phil

Gold $$ Contributor
For those of you that form 6 Dasher cases with the false shoulder method........

After removing the firing pin, and the ejector, how far will your bolt fall when your case is headspace to your liking?

So many different opinions on this, i`m just curious what results others are getting and their process.


Phil.
 
+3 on the full crush. I run a fairly healthy crush...gives me great brass!! I don't use so much that I have to push the bolt forward...just down.

Good luck,
Tod
 
I set that false shoulder so that last 10-15 degrees of bolt throw take a little effort. Don't want to force it and dont want it to go easy. I want to know that last little bit of camming in the action is snugging that false shoulder into the chamber and the case head in the bolt face. For me this method has produced accurate loads that fire-form nearly perfectly. Always trim after forming for best uniformity.

My $.02 added to the kitty....

Steve :)
 
Phil -

About any of the methods will make em Dasher's just fine, but myself I want consistent blow lengths, which in my experience directly reflects to capacity and variances there of. What the over-all lengths get blown to is dependent on the method and the load used. Myself I strive to hold a 0.004"-ES to blow lengths. I like it when they blow to +1.545"-OAL on the average, but regardless of the OAL average, I want the consistency in blow lengths.

To date, of all the methods I've tried, I've had best results with the false shoulder method, .264 expander with crush the whole way on bolt closer, with the bullet into the lands (.015"-ITL) but not at a hard jam.
Unlike some others, I use a light neck tension, and want to rely on the false shoulder as the dominate factor to headspace off for the blow.

My 2-Cents
Donovan
 
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Donavan,

Do you anneal before you expand the necks? Or, do you expand with a .257 and then a .264 or go straight to the .264?

Thinking about doing this with my new Lapua brass.
 
Terry -
I start by running them on a K&M .243" expander mandrel, chamfer, neck turn (to the shoulder), and end by polishing the chamfer & neck ID. Then I proceed to making the false-shoulder by going on a K&M .264" expander mandrel. I don't anneal them.
Donovan
 
Dragging this one up to clarify something....after reading 3 pages of dasher search threads on the false shoulder technique this one intrigues me the most.

When you guys want a "whole way as a crush" can you explain a bit to a dasher newbie? I'm guessing you set the false shoulder far enough towards the bullet so that when you close the bolt it "crushes" the false shoulder? Does it make the bolt hard to close (as in you really have to force it down) the entire way and is this normal?

I read also above to just make the false shoulder long enough to have the bolt kind of hard to close in the last 10-15 degrees of bolt closure...

If you crush the entire way and for whatever reason have to open up the bolt to eject the cartridge is that an issue when you close it back down on that same cartridge ? (such as a very strict range that when they call a range break they mean cease fire immediately)
 
Make sure to lube the bolt lugs you could gall the bolt lugs with lots of tight closes! Also don't set the case too tight you just want resistance on the bolt close with the ejector and firing pin removed.

Glenn
 
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Dragging this one up to clarify something....after reading 3 pages of dasher search threads on the false shoulder technique this one intrigues me the most.

When you guys want a "whole way as a crush" can you explain a bit to a dasher newbie? I'm guessing you set the false shoulder far enough towards the bullet so that when you close the bolt it "crushes" the false shoulder? Does it make the bolt hard to close (as in you really have to force it down) the entire way and is this normal?

I read also above to just make the false shoulder long enough to have the bolt kind of hard to close in the last 10-15 degrees of bolt closure...

If you crush the entire way and for whatever reason have to open up the bolt to eject the cartridge is that an issue when you close it back down on that same cartridge ? (such as a very strict range that when they call a range break they mean cease fire immediately)

It should require the meaty portion of your hand (directly under the thumb) to close the bolt. If you have a means of measuring chamber headspace, add .006" to that. That would require you to use the meaty portion of you hand.
 
RenoMD,

Watch this video, starting a 1.05 and you will see the bolt close they are talking about.

NOW.......

This video is NOT about forming cases, but finding the lands, however it does demonstrate what you are after with a stripped bolt for closure on a false shoulder.....

 
Ah excellent that gives me more confidence fellas... I'm going to try both methods of false shouldering and jam and shoot and see what blows more consistently in my setup.

What I was worried about that was described by Donovan, was if you create a false shoulder but crush the entire bolt close, wouldn't that form a gigantic donut, upon closing the bolt? but he has pics of his fireform brass coming out just fine, so he knows what he's doing...I'm just a trust but verify type of guy. Thank you again!
 
When you turn the neck all the way to the 6BR shoulder, you guarantee that the brass below the false shoulder is the same thickness as that above, so no doughnut. To review, doughnuts come from thicker shoulder brass being forced up into the case neck. What you asked about is exactly what happens if I don't turn into the shoulders of my expanded .220 Russian cases ( so that the cutter's bevel makes a full width track on the shoulder) . If I only turn to the shoulder, it takes a lot of force to close the bolt, and that forces some shoulder brass up into the base of the neck, forming an instant doughnut. Unlike the false shoulder situation of the Dasher, for the PPC I just want to feel the shoulder, with little or no crush.
 
So my process was using a 21st century expander die and 264 mandrel, then removed the internals from a 6mm dasher Forster FLS die, kept sizing down moving the false shoulder back and tested it by Trying to close the bolt on the brass .... finally found a great spot where it felt like I was crushing the whole way. However, I noticed a few things. A mushrooming on the rim after sizing back down, and when I made a dummy round based on where I felt the lands (on a prior test) the bolt wouldn't close. In fact I couldn't get the bolt to close despite pushing the bullet .050 off the lands. I removed the bullet and realized that the false shoulder I created and neck diameter were all expanded further outwards when I seated the bullet so the previous false shoulder depth I determined did not work anymore once a bullet was seated.

My question is after you all make the false shoulder do you re expand with a 6mm mandrel for good measure prior to testing it in the rifle chamber to see how far the bolt closes? Do you leave the internals with expander ball in the sizing die that you use to size back down and create the false shoulder width so that the neck is opened back up to 6mm?

Searching didnt reveal much in the way of the exact process and details those have successfully done this technique with.

I feel like I'm so close to making this work.
 

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