6 dasher neck turning

[potatoe]

I was wondering about creating the false should for fire forming dasher cases using the neck turning technique. How do you guys adjust your turning mandrel so precisely to stop cutting exactly where the shoulder needs to be? All I can think of is trimming a little, trying to chamber, adjust the mandrel, repeat. But is there a more precise way, do you guys use a neck turner that allows you to micro adjust the mandrel?

 

[bozo699]

Potatoe,
I probably shouldn't even comment as I don't shoot a dasher or use that method to fireform I was going to but used another mehtod instead. I have a 6brx, very similar to the dasher, I figured I would find the measurement of the necks length and set the turner to take a few thou. more as it is a good idea to turn past the neck/shoulder junction anyway. The reason I was going to turn the necks in the first place I though I was going to have to for the loaded rounds to fit the chamber but when I got the gun back from the smith it wasn't the case, so I just jammed the bullet hard and fireformed that way, worked great.
Wayne.

 

[ridgeway]

All I can think of is trimming a little, trying to chamber, adjust the mandrel, repeat. But is there a more precise way, do you guys use a neck turner that allows you to micro adjust the mandrel?

That's it. I remove the firing pin when setting mine up. The K&M a depth stop attachment that attaches to their cutter.

 

[Switchbarrel]

I assume you've got a tight necked chamber. I'm relatively new to the round also. I stayed away from the Dasher for a long time because I was worried about the same thing...trying to figure out where to stop on the neck with my turner. Then, finally a lightbulb went off and I realized by expanding/necking back down to create the false shoulder and then forming with the "Cream of Wheat" method, neck diameter didn't matter (mine's not so tight a case won't chamber) since there was no bullet to worry about. I could blow out the cases first and turn necks second. Contrary to everything I'd read, it's not that messy, just loud (I turned my garbage can on it's side a few feet away and fired into it in my garage). Later I just drove out into the country where nobody was around and fired off a bunch. I have an annealer so I'm not too worried about overworking the brass as some might fear with this method, I only lost 1 case out of two hundred formed.

My second Dasher is a no-turn neck, I've just started loading a round, jamming a tightly held bullet into the rifling and shoot a low-end Dasher load (about 29.5 gr. of RL15) I lost a couple cases with a higher charge. I've formed a 100 this way so far, definitely an easier way to go.

-Rick

 

[potatoe]

Thanks for the info guys i really need some pointers. My build was originally going to be a no turn neck but with the blue box brass changes, a .273 neck (the reamer the smith has) is not appealing and I'm looking at the .266 neck dia. for my build

One idea I had was (at the expense of loosing atleast one case) was turning the whole neck first, then expanding the neck (.257) then sizing it back down to 6mm till the case fit in my chamber. Then setting my neck turner to where it stops turning the necks as soon as it 'buffs' the false shoulder of .257. From then on I could just turn my cases, without expanding the necks of course, to a fit the chamber without much guess work. Does this make sense to anyone? I thought it was quite good, but could always use some input.

 

[mikecr]

With your expanding to 25cal, you've already created your false shoulder.
So why do you want so badly to partial turn your necks?

 

[potatoe]

Mike: Because it's a .266 neck

 

[mikecr]

Ok, i'm following now..
But I don't know which turner system you're using.

As Bozo mentioned there is the resultant donut to address. I like your idea of pre-turning before creating the false shoulder. This halves the donut, and you could pre-turn to ~half way between the new shoulder and original.
Or you could simply headspace off a turn(trial & error), as originally questioned, then inside ream the resultant donut after fire-forming.
I'd measure & scribe a neck for a new shoulder line. Then insert the neck to the mandrel stop(with the mandrel loose). Then slide the mandrel back until the edge of the cutter lines up & tighten the mandrel.
Just as a starting point.

 

[lynn]

You can neck one case up to 25 caliber and size it back down a little bit at a time until you bolt closes with some exta effort.
You then turn righ up to the neck/shoulder junction on that one case.
Now you can use that case to adjust your neck turner stop.This method allows you to turn all the necks on your 6BR brass straight out of the box without worrying your going to deep.The donut is a non-issue because the neck will shorten on fireforming.
I still prefer the false shoulder method and 15 grains of red dot under cream of wheat with a slightly lubed case.
Lynn

 

[bozo699]

Potatoe,
I don't think this will be difficult, its just new territory and were hesitant when were playing with buck a piece brass, the way I see it you could turn the whole neck on a br case and measure after you fire it what your going to need or you could measure before you start , I would opt for # 2 if you can read a mic or caliper.


6mm DASHER
The popular Dasher is very accurate and has set many records. It has a bit more neck than the BRX. Gunsmith Dan Dowling is credited with its invention. It offers about 3.5 grains (10%) more case capacity than the standard 6BR–good for an extra +130 fps with a 105gr bullet. Effective out to 1000 yds, the Dasher holds the NBRSA 6-target 1000-yard world record Agg. Pacific Tool & Gauge (Dave Kiff) is a good source for 6 Dasher reamers. Specs: 40° shoulder, blown forward .10″, Neck-length = .246″. Requires Custom Dies.

Now if it were me I would take a 6br case and measure down it .246, add another .010 or so that way it will make it past the neck/shoulder junction, so I would scribe the case at .256 then set the turner up to trim to the mark, I would trim the minimum amount needed to safely fire in your chamber, then load and heavily jam a heavy flat base bullet and fire it. If you like what you see, do the other 99 cases, then reset your turner for a final cut for the exact neck clearance you desire I personally don't like the cow method, its messy and the shoulder rarely forms correctly, good luck however you do it.
Wayne.

 

[potatoe]

You can neck one case up to 25 caliber and size it back down a little bit at a time until you bolt closes with some exta effort.
You then turn righ up to the neck/shoulder junction on that one case.
Now you can use that case to adjust your neck turner stop.This method allows you to turn all the necks on your 6BR brass straight out of the box without worrying your going to deep.The donut is a non-issue because the neck will shorten on fireforming.
I still prefer the false shoulder method and 15 grains of red dot under cream of wheat with a slightly lubed case.
Lynn

Lynn, I wouldn't think that a piece of unturned brass would chamber in a .266 neck?