My personal nightmare with 6.5 rsaum

[Kevin9934]

So, i need advice for the 6.5 rsaum masters!

I just made the acquisition of a new custom precision rifle in 6.5 rsaum.

I have read the care and feed post of PsSinclair but i have issue.



After using and following the instructions, i still have .003 of run-out before making any kind of fireforming. After fireforming it is another story.

-My question is , in the care and feed post doe he mean that after the forming process he have almost no run-out? because from all my test it is impossible.

-So he was meaning that after he fireform hes brass, THEN he have a <<stellar>> run-out?

-Also using 7 saum brass to make 6.5 brass , why he trim to 2.025 ? The reamer print is at 2.025... really to close and not usable

Another thing is:

-When forming , the brass will create a doughnut. How do you take care of this?(without a KM carbide mandrel with cutter, since i am already with 21 century)

Then come to my mind, that the Die he and i are using is not a real full lenght sizing die since:

This is because the bushing cavity requires a shoulder (about 1/16 thick right above the neck shoulder junction) inside the die to hold the bushing in place, without it, the bushing simply falls down into the die.

What this means is you have a portion that always remains unsized, you can see this unsized portion on your sized brass right above the neck shoulder junction. Since you can't close that portion, your expander can't expand the donut (if there is one) out.

So How do i make correct brass that have good run-out(less than .001)

Thanks
BOb

 

[Rthur]

I didn't see where you said you turned the necks. As thick as the factory 7saum brass is this is likely to increase as sizing down. How are you measuring run out? A portion of this reading could be from the different neck thicknesses from side to side. An expander mandrel can move the problems to the outside to be addressed by the neck turner.
How do these rounds shoot?

R

 

[[email protected]]

Don't shoot this caliber but I've seen similiar problems.

What expander are you using, and are you turning the brass into the shoulder?

I always see a little bit of runout when expanding, and usually see donuts if not turning the brass into the shoulder.

 

[Kevin9934]

I Use:

Redding kit: 36280
Bushing: 308/303/298/295(in this order)
Expander: 21 century TIn coted mandrel
Neck turner: 21 century TiN coated mandrel
Brass: Remongton 7Rsaum
Trim lenght 2.015

Neck turned at: .015
Press: forster co-ax with shellholder adapter and also tested with std jaws.

I will try fireforming COW methode this week end. Form 3 gr of red-dot to 25gr. will see.

The point is:

-You dont know where exacty the neck juntion is due to brass moving in this area do to neck sizing. So you can cut to far and weaken the junction..ask me how i know..
-The die is not sizing all the way(impossible by design) so the expander cannot move the doughnut outside.
-i think you absolutly need to fireform for this caliber
-I dont have alot of experience so im lost...lol

I would like to have the imput of the guys who have worked the caliber like george and PsSinclair

 

[Rthur]

Contact Copper Creek on the Hide. You will want to talk to Josh. He is the source for 6.5 saum brass for George's rifles.


R

 

[Kevin9934]

Alright

I think i got it fugured out.

Here is my fireforming results:

Tested 3gr to 23 gr of red-dot

Run out for formed case is
From 3 to 8 is at .0005 to .0025
From 9 to23 is at .0005 inch

I then just expanded the 23gr case and neckturned it and the run-out is still stellar(.0005)

Now i have tried it differently with another case(the 22gr formed) .
For this one i have full/neck sized to .295 , expanded and then neck-turned.

Run out on this one is .001- .0015

My question is:

What is the best sign that my brass are properly fireformed? Shoud i try higher than 23 gr if reddot?
What measure should i do? Headspace grow, neck O.D...any other?

Should is just expand afther fire-forming and neck turn or full/neck size ,expand then neck turn?

What run out is acceptable for accuracy.
.0005?
.001?
.002?
.003?

Thanks

 

[Nate O.]

What run out is acceptable for accuracy.
.0005?
.001?
.002?
.003?

Thanks

My runout is generally around 3-5 thous. I think if you mixed a bunch of ammo together with "good" and "bad" runout and didn't know it, you'd have a tough time telling what was good and bad from the results on target. Been my result anyway.

If you're getting .005 or less, you're good.