O.A.L. for dasher/br/brx with .104 freebore

[Shawnba67]

I am curious what OAL guys running the dasher or brx are ending up at with different bullets, especially interested in 105-115's.
Im trying to determine if ill be able to eject loaded rounds from a 22-250 based rem 788(this is not a standard SA) thank you

 

[dmoran]

Less then 2.4" -- around 2.375-ish (at the rifling) for most 105 types

 

[kountryboy2]

Less then 2.4" -- around 2.375-ish at the rifling

Thanks! I was wondering the same thing. What method do you feel is best for fire forming Lapua brass?

 

[dmoran]

@kountryboy2
As to method, in some ways can kind of depend what one plans to use them for.
With that said, I prefer the "false shoulder" method using a 6.5-cal expander.
Equality in "blow lengths" is the aspect I strive for, which directly effects case capacity - IME.
All the methods will basically produce "squared shoulders" and good looking cases !.!.!
But a mild to medium tuned charge, with a wide false shoulder, is what has prevailed best for me with my own endeavors and desires to forming consistent cases.
Donovan

 

[Shawnba67]

I was gonna use the Norma Dasher brass from bullets.com?? Any reason not too? Has anyone seen the thicker rim cause extractor issues?

 

[dmoran]

@Shawnba67
If your new to a 6Dasher, and not already established with dies and chambers based around Lapua mades, then going with the Shiraz/Norma 6Dasher cases and setting up around it instead is a good option. I would myself if was just getting going with it.
Good Luck
Donovan

 

[kountryboy2]

@kountryboy2
As to method, in some ways can kind of depend what one plans to use them for.
With that said, I prefer the "false shoulder" method using a 6.5-cal expander.
Equality in "blow lengths" is the aspect I strive for, which directly effects case capacity - IME.
All the methods will basically produce "squared shoulders" and good looking cases !.!.!
But a mild to medium tuned charge, with a wide false shoulder, is what has prevailed best for me with my own endeavors and desires to forming consistent cases.
Donovan

Thanks,Donovan. I think I'll start with the false should method just like you described.

 

[Kyle Schultz]

Donovan is offering some good advice. I will mention, however, I personally could not get the false shoulder method to yield what I consider acceptable blow lengths. Despite my most careful efforts, I was only achieving blow lengths of about 1.526".

Before resorting to hydroforming, I decided to try the jam method. Initial results were encouraging and just today I fire formed 82 pieces of Lapua Blue Box 6BR brass. No losses. Generally seeing about 1.542" after fire forming. This was using SMK 107 jammed 0.020" and 0.025" and various charges of Varget running from 29.8 to 30.6 grs. Working on the statistics now to see if there is an optimum jam and powder charge value.

I'm sure with additional work I could have achieved similar results with the false shoulder method. But the jam method appears to be working and requires much less prep work.

Regarding the Norma 6 Dasher brass, I've invested almost 700 rounds and 2 barrels trying to establish it as a viable alternative to reformed Lapua brass. My biggest issue is losing primer pockets as I try to push velocities up to typical 6 Dasher levels of 3000+ fps. I'm not convinced the brass won't ultimately be proven to be successful. I just can't/don't want to spend any more time, components, and barrel life trying to upstage what has been universally established as a proven winner.

Good luck with your efforts.

 

[kountryboy2]

Thanks Kyle,
It's nice to hear other shooters methods. This is new territory for me so I have alot to learn.

 

[Pakratt99]

Has anyone done a comparison between False Shoulder, Jam and the Cow method in regard to OAL?

 

[Kyle Schultz]

Here are the results of my fire forming efforts today using the "jam" method. I was only getting about 1.526" with the false shoulder method but it is very likely my methodology was flawed. "Jam" method is pretty idiot proof.