6 Dasher False Shoulder Setting Technique?

[bsumoba]

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.

I have had mushrooming on my necks after sizing back down to 6mm when doing a false shoulder. This seems to be normal.

What is the neck diameter for your chamber and what is the loaded round neck diameter? It could be that your chamber neck is too small once you load a round. This means you need to turn your necks down. Mine is a .271" neck and my loaded round is around 0.267-0.268"

 

[Phil]

Did you chamfer the neck before sizing down / seating the bullet????

 

[RenoMD]

Hey fellas thank you for the replies, necks were not chamfered before sizing back down. Is that to prevent mushrooms? I got a 272 no turn neck. The mushrooms actually faded away when I seated a bullet but couldn't close the bolt any more I'm going to measure my other unloaded false shoulder cases at the neck and false shoulder diameter, and compare to the current false shoulder dummy round

 

[Phil]

It helps reduce the amount of mushrooming that I get on my cases.

Since I need to chamfer the inside / outside of the necks anyway, I figure that I should just go ahead and do it....

 

[RenoMD]

It helps reduce the amount of mushrooming that I get on my cases.

Since I need to chamfer the inside / outside of the necks anyway, I figure that I should just go ahead and do it....

Loaded round neck diameter .2675 right at beginning of the neck, 268 with calipers just below neck bullet junction, neck 2695 between neck bullet junction and false shoulder, just before the false shoulder goes to 270, the false shoulder is 288

Edit: yeah problem solved I just ran a 6mm expander in, then I had to back the false shoulder about 1/16th turn of the fls dasher die down, and re-expanded with a 6mm and it worked. Probably overworking the brassa bit too much. Let's just hope the necks hold up on fire forming

 

[fguffey]

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, I do not remove the firing pin, I do not remove the extractor or ejector. I determine the length of the chamber from the shoulder of the chamber to the bolt face. There has to be at least 3 different ways to accomplish that. And then there are assumers, they assume be4cause someone told them they had to do it.

F. Guffey

 

[fguffey]

Probably overworking the brassa bit too much. Let's just hope the necks hold up on fire forming

Sacrificing a few cases is a small price to pay. I am the fan of not starting over every day.

F. Guffey

 

[dmoran]

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[fguffey]

I have had mushrooming on my necks after sizing back down to 6mm when doing a false shoulder. This seems to be normal.

Bsumoba, I have said moving the shoulder back on a case is an illusion. I have made it very clear I can not move the shoulder back on a case with a die that has body support. And now you have made it more complicated because the only way I can move a shoulder back on a case is with a die that does not have case body support. Instead of the 'the mushroom' I turn the case into an accordion or a case with bellows.

I never intended to create a case with bellows or something that looks like an accordion but when I want to know if my cases require annealing I go for it.

F. Guffey

 

[LRPV]

Phil, I do not remove the firing pin, I do not remove the extractor or ejector. I determine the length of the chamber from the shoulder of the chamber to the bolt face. There has to be at least 3 different ways to accomplish that. And then there are assumers, they assume be4cause someone told them they had to do it.

F. Guffey

Then sir, you are doing it wrong. Plain and simple.

 

[fguffey]

Then sir, you are doing it wrong. Plain and simple.

Not my intension but I did leave out the part being the only one that can, I omitted the part about being the only reloader on this forum that can measure the length of the chamber from the shoulder of the chamber to the bolt face. A reloader that has the ability to measure the length of the chamber from the shoulder of the chamber to the bolt face can go straight to forming/sizing cases.

The same person that can measure the length of the chamber can measure the length of the case from the shoulder to the case head when deterring clearance.

And then there is that other part; I off set the length of the chamber with the length of the case from the shoulder of the case to the case head. I know, it sounds cool when a reloader talks about removing the extractor, ejector and firing pin. Problem comes when the reloader install all of that hardware and the bolt will not close.

And they also spend a lot of time talking about go-gages.

F. Guffey

 

[fguffey]

Then sir, you are doing it wrong. Plain and simple.

You guys spend so much time being rude I have a lot of trouble taking you seriously. I do appreciate the "then sir". Anyhow, I can measure the length of the chamber 3 different ways, I have never had someone tell me I couldn't. I never asked, I simply sat down, looked at it and then started putting tools together. And then I wondered why would a reloader would need three gages like go, no and beyond when one would do.

F. Guffey

 

[LRPV]

You guys spend so much time being rude I have a lot of trouble taking you seriously. I do appreciate the "then sir". Anyhow, I can measure the length of the chamber 3 different ways, I have never had someone tell me I couldn't. I never asked, I simply sat down, looked at it and then started putting tools together. And then I wondered why would a reloader would need three gages like go, no and beyond when one would do.

F. Guffey

No rudeness intended. I would guess that the majority of Dashers are being shot with custom actions. It is not a big deal to twist the firing pin assembly out of my BAT and push the ejector retaining pin out. It is then very simple to begin putting a false shoulder on an expanded BR and checking the fit. It is very easy to do this process and in my opinion needs to be done this way with the proper "feel" to get a case to form correctly. I never once said that your way can't work but mine is so simple I can't imagine why anyone would want to pull out whatever measuring instruments it takes to measure where the false shoulder needs to be put on a Dasher case.

 

[fguffey]

No rudeness intended.

When a reloader tells me he moves the shoulder of the case when bumping? I ask; "How do you do that?" I qualify the questions with: "I can not move the shoulder back with a die that has case body support".

I am beginning to believe most reloaders do not know and I believe they are a little sensitive. I find it very easy to say "I do not know". I understand there are fire formers and there are case formers, fire formers chamber a round, pull the trigger and become fire formers. Again, I get that. I form first then fire, basically after I fire the case I eject a 'once fired case'.

I do have wildcats with short necks, one of them has a neck that is .217" long, my opinion, that is too short if the 300 Winchester Mag neck is considered short at .270". The shoulder on the wildcat is ahead of the parent case by .202". That is the perfect candidate for the false shoulder, I choose to form the cases with longer cases. And then there is measuring before and again after forming and fire forming shortens the length of the case, from beginning to end forming and fire forming shortens the case length of the wildcat case .045"; and now we go back to the part where I said the neck is short and If I can managed to length the case length I can increase the length of the neck.

F. Guffey

 

[Alex Wheeler]

When a reloader tells me he moves the shoulder of the case when bumping? I ask; "How do you do that?" I qualify the questions with: "I can not move the shoulder back with a die that has case body support".

I am beginning to believe most reloaders do not know and I believe they are a little sensitive. I find it very easy to say "I do not know". I understand there are fire formers and there are case formers, fire formers chamber a round, pull the trigger and become fire formers. Again, I get that. I form first then fire, basically after I fire the case I eject a 'once fired case'.

I do have wildcats with short necks, one of them has a neck that is .217" long, my opinion, that is too short if the 300 Winchester Mag neck is considered short at .270". The shoulder on the wildcat is ahead of the parent case by .202". That is the perfect candidate for the false shoulder, I choose to form the cases with longer cases. And then there is measuring before and again after forming and fire forming shortens the length of the case, from beginning to end forming and fire forming shortens the case length of the wildcat case .045"; and now we go back to the part where I said the neck is short and If I can managed to length the case length I can increase the length of the neck.

F. Guffey

I read your posts and wonder what it is your trying to accomplish? When we size a case in a full length die we shorten the distance between the case head and shoulder. Are we pushing the case head up or pushing the shoulder back? Who cares. Its commonly known as bumping or pushing the shoulder back. We all understand what each other is taking about. You confuse me and no doubt a lot of new reloaders with what ever it is your trying to do here.

 

[LHSmith]

^^^^^AMEN !

 

['Freak]

You guys spend so much time being rude I have a lot of trouble taking you seriously. I do appreciate the "then sir". Anyhow, I can measure the length of the chamber 3 different ways, I have never had someone tell me I couldn't. I never asked, I simply sat down, looked at it and then started putting tools together. And then I wondered why would a reloader would need three gages like go, no and beyond when one would do.

F. Guffey

Show this ‘reloader’, and if you can’t or refuse to do so, then it never happened …

 

[Sheldon N]

"I can not move the shoulder back with a die that has case body support".

Nonsense... the brass compresses and extrudes forward and that's why you can see increase in case length when full length sizing. On cases with sharper 40 degree shoulders the extrusion can happen internally inside the case rather than in length (ie donuts).

I am beginning to believe most reloaders do not know and I believe they are a little sensitive. I find it very easy to say "I do not know".

But you apparently have a harder time refraining from providing input when you do not know. Your posts are full of obfuscated language and half truths that don't help anyone.

 

[fguffey]

Nonsense... the brass compresses and extrudes forward and that's why you can see increase in case length when full length sizing. On cases with sharper 40 degree shoulders the extrusion can happen internally inside the case rather than in length

Reloaders have an infatuation with moving the shoulder back, they use the 'bump the shoulder back' and I have insisted moving the shoulder back is impossible. I can shorten the distance between the shoulder of the case and case head, I can not do it with a die that has case body support. And then we go back to moving the shoulder; does the shoulder move? And then there is "I fired the case and the shoulder moved forward and again I ask; did the shoulder move?

I do not expect answers but I was thinking someone on this forum would have an ideal, and then there is a very remote chance someone would say something like "I have never given it a thought but I have always assumed the shoulder moved".

F. Guffey

 

[Sheldon N]

Obfuscation.

Next time you get pulled over explain to the officer that you were not driving 65mph in a 55mph zone, but rather that the world was actually rotating under your wheels as you were remaining stationary in absolute space relative to the rotational position of the sun, moon and galaxy.