Dasher blow length

[harv50]

:-\
Seems like everything I read about the correct blow length for Dasher cases is around the 1.553 length.
I can only get between 1.544 / 1.546...
I started with to low of a load and got 1.533 and worked my way up to where I getting the 1.544 /1.546 area with anywhere
between 32 gr and 33 gr of varget (32 gr made the same blow length as 33 gr)
I'm using the expanded neck (.257) necked down to a CRUNCH fit and heavy neck pressure (.267 loaded round, .263 bushing).
I'm sure the case isn't moving with the crunch fit, bullet in the lands 20-25 thousands.
I've tried Rem 7 1/2, CCI 450's, and 205 Fed's with the only diff being gratered Fed primers @ 32.5+ load);
Any idea why I'm getting what seems to be a "short" blow length.
Maybe it is just the way my chamber is but thought I'd see if anyone else has had this "problem".
It might not even be a problem as I haven't tried to work up a load yet, Just fire forming now but don't want to have a bunch of wasted cases from being to short of a blow.......

 

[LHSmith]

What the heck is "blow length" . I've been reloading for 45 odd years, done wildcats for 20 years, and I never heard this term. Is it in the glossary of reloading manuals? If not, please use the proper terminology so as not to confuse people. I rather this forum not revert to words which need translation in the"urban dictionary"

 

[Hal]

LH

Blow Length : It's the final case length ,after a case is fire formed.


Hal

 

[potatoe]

He is referring to the length of the case after fireforming an improved or wildcat cartridge. Its the correct term as far as I know.

I too had a dasher that would form them down to around 1.540- 1.545. My pops (today actually) formed his first dasher cases and they were shrinking as short as 1.535. Some of the other dasher guys should pop in with some possible tips to forming them, but I've heard that the new blue box tends to shrink more than the gold but I can not confirm this.

BTW I used the exact method that you did for form the dasher cases.

EDIT: The OP didn't start a thread about correct terms, he used a term that is used quite often. Plus I doubt there are many reloading manuals out there for a dasher, thats why he is on this forum asking a specific question.

 

[firearmdoc1]

Why not use commonly understood terms such as fire form length or cartridge length?

 

[LHSmith]

Why not use commonly understood terms such as fire form length or cartridge length?

Exactly....If you google that term you find hair drying techniques and x-rated sites. This is how slang words start, like Remmy and Winny and "heads" as in .308 "heads"....they're bullets!!! or even boolits if you wish......they ain't no heads. The "head" is either part of a cartridge case or the latrine. End of rant.

 

[LHSmith]

EDIT: The OP didn't start a thread about correct terms, he used a term that is used quite often. Plus I doubt there are many reloading manuals out there for a dasher, thats why he is on this forum asking a specific question.

Where has that term been used? I 've been viewing this site regularly since '05, been a member since '07 and this is the first time I seen that term. The Dasher isn't the only case that ever required FF, they have been FF for wildcats for years and was commonly known as FF length....not using a term commonly used in the drug culture. Let's not go there.

 

[potatoe]

http://forum.accurateshooter.com/index.php?action=search2

"blow length"

P.S. Sorry Harv for molesting your thread.

 

[Frankr]

It is a very interesting subject. I just started with my first dasher and have had short cases. 1.525-1.530ish
I got some help from johara1 . He seems very knowledgeable . or should i say is very knowledgeable.
I have not had a chance to try fireforming any more to see if i get the right blow lenght.
My chamber is 1.555 and i have a 104FB so i dont think im hurting too bad being .030 short of the chamber and it does seem to shoot well.

But harv50 i would suggest you try a few things, get rid of the crush on the steped neck. neck it till the bolt closes easy. really you are just going to use the steped neck as a security measure. you need a few thousands of headspace. jam your bullet with the heavy neck tension as you have been. use a heavy bullet. 105,108 ect.

use a non chlorinated brake cleaner, on a Q tip clean inside the case neck, clean and dry.

use the brake clean, a chamber mop or big patch, clean the chamber. clean and dry.

use the brake clean on a paper towl clean the loaded case. clean and dry case.

try that and see if you get one to blow to 1.555

johara1 am i in trouble for giving up top secrets?

 

[Hal]

LH

Congratulations You learned something new today.

Hal

 

[Frankr]

LHsmith i think the term blow lenght is common to the dasher because you are not just trying to fireform a case to the chamber but you are trying to get the case to blow forward with out stretching the web or shortening the neck. which is what happens when you do not blow the case correctly you just fireform it to the chamber and in doing so you just shorten the neck . but i have only shot mine a few times. I have never tryed to tune a load or do any accuracry work with it at all and it just shoots. I think im really going to like this 6 dasher as soon as i become a case forming expert.

 

[harv50]

WOW.....
Guess I got taken down a notch there LHSmith....
I've been reloading now for 43 years (15-63) and I've heard both terms...Mostly in the last
7-8 years I've heard it called blow length....
But that is beside the point...
Fjim...I've done everything you suggested..(on the advice of Johara1, BY the way thanks "J".
the one thing I haven't tried is not making the Crush...
Thanks everyone...I'll keep at it..If they don't go longer I'll just use them @ what seems to be short...If they are within a thousands or so the capacity should work out....

 

[blipelt]

harv50 how do the shorter cases shoot?

Brent

 

[harv50]

I was just "Fire forming, lol)
and using some old 105gr Hornady,,, not the 105 h's I plan on using...
They were in the low/ mid 3's...

 

[blipelt]

.3's fireforming should make anyone smile. If it was me(which it was last year) I would load some up and go out and see what she does. The words of wisdom that ring in my ears are: "Keep it simple, consistent, and go have some fun".

Brent

 

[Frankr]

you know one real interesting thing with the dasher is. I was chrongraphing some loads,just breifly testing a few loads. My barrel is 26" I got 2,950's with 33.0 gr RL15 and it shot well with no tuneing work. went up to 34.0gr and it was 3.075 FPS but it was a little hot. I was telling a friend of mine about it. he said he has a hard time getting that kind of speed out of his .243 win. it just amazes me just 33 grs of powder. this was a 105 VLD.

I cant wait to get one built in a medium weight sporter rifle.

 

[johara1]

Term change over the years, and go back more than i care to remember. So why do people get bent out of shape on a term used to define this operation? I would be more upset with false information, like lubing a case to make it longer. Blow length is a term used the same as any other it seems the people involved with it know what it means and those that don't don't need to worry about it. I don't nit pic over terms but i do on the target,where it counts....... jim

 

[treeman]

I haven't done a dasher yet but I have done 6brx's with brown box lapua I had no problems. I had some new 7br r-p and decided to form it and see how it worked and they came out real shortsome as short as 1.517" I should have loaded at the range and came up with a method that made longer brass. it seemed like it sucked it into the chamber in stead of blowing it