need advice making a false shoulder, fire forming and couple other 6mm dasher ?s

[omahaguy]

ok all things considered I think I may go with the dasher, but I need advice on how to make a false shoulder, what kinda of neck up die do I need and where do I get it? also how much powder do I need to fire form, I read something about someone doing it without bullets, so itll save on barrel wear, how do I neck back down? I am completely new to this wildcatting thing and could use a thorough walk through. I hope that the dasher can push the 105gr nosler customs into and past the 3000fps range.
Also does the dasher have any problems feeding from a mag?

Thanks in advance for any and all help in this matter it is greatly appreciated

 

[skeetlee]

I am not the best one here to give advise, but i have been doing just what your asking and it is working very well for me. 1st i take a 6.5mm neck sizing mandrel that i bought from Sinclair's. and neck a up a piece of 6BR brass. The neck sizing mandrel and mandrel die are available at Sinclair's and are not that expensive. I think i have 35 bucks in the two pieces. Ok, The i get my rifle out. I take the necked up 6 BR brass and place it in the shell holder and run it up in my 6BR Full length size die. the trick here is not to go to far. go about half way down the neck and stick the piece of brass in the rifle and close the bolt. The way i understand it you want a little resistance when closing the bolt. you want to feel it, if you will. If the bolt closes to easy i think you need to back the die adjustment up and try again. If the bolt will not close, adjust the die down a little at a time until it will close and you still feel a little resistance. thats about all there is to it. I am using 31 to 31.5gr of RE15 to form my cases. your mileage my vary. I dont think you want to go much lower than 31gr if your using RE15. i tried 30gr and i didnt get a very sharp shoulder. It seems overwhelming but it isn't bad at all. The good folks here helped me through it. Do a little more research before diving in. Like i said i am probably not the best to take advise from as i am still learning myself. I am getting really good results with my fire forming loads, with groups in the high .2's to low .3's . good luck and enjoy the dasher. Its a fun chambering! Lee

 

[Klong]

Skeetlee has it!

I also make sure my fireforming rounds have the bullet touching the rifling.

 

[flatlander]

+1 to the above replies. I started out using a Redding tapered expander button in a spare 243 FL die, also going clear up to a 6.5mm neck before partially sizing to create the false shoulder. The tapered expander is somewhat easier to pull the expanded neck back over; with the Sinclair expander, sufficient inside neck lubrication is critical because of the bearing length of the mandrel. I used to have to apply Imperial Sizing Die Wax with Q-tips in order to use the Sinclair mandrel.

Nowadays, I just set cases up on a lube block & shoot them with Hornady One-Shot case lube, then use a tapered .257" expander. I feel it's a little easier on the brass, and I know it's easier on me.

I wouldn't even consider fireforming Dasher brass using Bullseye & filler - as was mentioned, fireforming loads are very accurate with the same bullets you intend to use with formed cases.