6 dasher forming & dies

[BigDaddie]

Hi all,

I'm in the process of having a 6 dasher made. I have a few questions so please excuse my ignorance.

I have read the article on fireforming the brass suggesting that either a 25cal or 6.5mm mandrel should be used so u get a false shoulder. I understand the principle but how far down the neck should the sizing bushing squeeze it back to 6mm?

I am looking for a Redding Type S - FL die for the dasher. Looking in sinclair's cat, they only list 6mm Rem Improved 40deg. Is this the correct die? The gunsmith is going to use the reamer in a 6br seater for me so that wont be a problem. Loacating the right FL die is!

I will be using Lapua brass and the 107smk so could anyone suggest a suitable bushing to start with?

The rifle will be used in F-Class.

Kind regards,

BD

 

[techshooter]

I did not try the jam only technique, but went with the false shoulder. I used a 25 caliber expander, then ran the case into the Redding Dasher S type neck bushing die using a 0.267" bushing. I backed off the bushing just a tad so that there was a slight crush when chambering the empty case. This worked very well, as I lost only two cases to split shoulders over 500 rounds,32 grains IMR4895 with 107SMK), and the vast majority of the cases were within +-0.001" of each other in length after fireforming. The actual statistics for a large sample can be seen on my Dasher page under my web site below.

Cheers,

 

[BigDaddie]

Thanks for the information fellas. I have a forster die set on order for US$91. Unfortunatley the Redding does were going to cost me AU$270 which was a little rich at this stage.

Techshooter, I really enjoyed reading your field tests on your Dasher. That will help me when it comes to tuning my new toy.

 

[flatlander]

BD, You can't do much more than expand the necks of your brass until your finished rifle arrives, since you'll need the rifle to determine how far to size the necks. I've used the false shoulder method to fireform 1200 cases,400 ea. for three different barrels), and have lost about a dozen total to mostly shoulder splits. Two cases had creases in the necks right out of the box, and split on the creases when fired.

For forming, you want the false shoulder just far enough forward so that you can feel a little resistance when lowering the bolt handle while chambering the case - not too much, not too little. It's hard to describe the exact feel you're looking for with words, but a little experimenting on your part, and you'll figure it out.

 

[BigDaddie]

Thanks Dennis,

Im waiting on the tools at the moment so Im no hurry anyway.