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6 Dasher fire-forming loads- Load, Jam, and Shoot (not the false shoulder method)

RenoMD

Hi,
I didn't see a dedicated thread to using this method (Load, Jam, Shoot) for forming 6 dasher brass from Lapua 6mm BR brass, so I decided to start one. To those 6 dasher newbies (myself) this is NOT for the Norma brass chambering b/c your cases are obviously formed... I don't have a 6 dasher yet; but, one is on the way... from what I read (multiple threads from 2006 til current), and the 6mmbr articles of course really 3 methods of shaping 6 dasher brass... http://www.6mmbr.com/6improvedform.html it appears some well known and highly successful 6 dasher shooters (one of them in 6mm br articles) say just load jam and shoot, why create a false shoulder and overwork brass... to each his own. Loads I've seen work (in forums....see references below) are with various powders and bullets.

Loads seen in other threads/articles (bullet/powder/ jam depth):
-Sierra 107, Varget 30 gr, -0.010 http://benchrest.com/archive/index.php/t-71662.html
-Sierra 107, Varget 30 gr, -0.030 http://www.scout.com/military/snipe...53087-bighorn-dashers-mcr-rifles?s=541&page=3
-Sierra 107, Varget 29 gr, -.100 http://forum.accurateshooter.com/threads/fire-forming-the-6mm-dasher.3477205/
-Nosler 70 gr varmint ballistic tip, BCL-2 35 gr, -.050 (well known 6 dasher gun smith's fire forming load he shared)
-Hornady 105 gr amax, varget 29 gr, jammed -.040 (I can't remember where I saw this)
-Hornady 105, imr 4064 30 gr, "hard jam", cci 400s. (see below post).

Does anyone else have fire forming loads to share for the jam, load, shoot method without false shouldering?
 
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You can use any standard 6mm BR load. Just make sure if you are not using a false shoulder, you jam the bullets hard into the lands. Also use a soft primer like a 205M.
 
22DASHER said:
You can use any standard 6mm BR load. Just make sure if you are not using a false shoulder, you jam the bullets hard into the lands. Also use a soft primer like a 205M.
Click to expand...
I foresee a contest of golden proportion brewing.

I'm in the false shoulder camp. Neck up and neck down. The main reason is the prevention of the dreaded case head separation. The brass is trapped between the bolt face and false shoulder preventing case movement on firing. The jam method works on the same principle, but bullets and be shoved into the case when jammed.

Adam
 
22DASHER said:
You can use any standard 6mm BR load. Just make sure if you are not using a false shoulder, you jam the bullets hard into the lands. Also use a soft primer like a 205M.
Click to expand...

205Ms are hard to come by in most places apparently...I've had great success using Rem 6 1/2s.....
 
Use lots of neck tension and yes jam the bullets hard in the lands, enough that the bolt closes hard. I use 29.5gr of varget with Remington primers when I fireform.
 
I've got the components for my Dasher build using the jam/fireform method. 105 Amax (they were cheap but have decent BC), Fed 205 primers, H4895 powder, Lapua brass. Not going to expand the necks or touch the brass pre-firing, virgin Lapua has lots of neck tension. 0.030 jam at around 29-30g of H4895, will target between 55-60k PSI per quickload. I'll probably run some sort of OCW style test with the fireforming loads to see if I can get a good shooting load since I do have 300 cases to get through and may shoot some local square range matches with them.
 
Didn't want to waste my RL15/Varget so used 30.0 imr4064, cci400's lots of neck tension and hard jam. Outstanding accuracy as well
 
Wow quick responses, thanks for the info.

Another thing I saw, I have a question about, is someone mentioned in general not fire forming with moly coated bullets; but, didn't give an explanation why... I can't think of a reason why this would be a problem fire forming 6 dasher with lets say hornady 105 amax moly bullets. Anyone have experience with this? Thank you!
 
RenoMD said:
Wow quick responses, thanks for the info.

Another thing I saw, I have a question about, is someone mentioned in general not fire forming with moly coated bullets; but, didn't give an explanation why... I can't think of a reason why this would be a problem fire forming 6 dasher with lets say hornady 105 amax moly bullets. Anyone have experience with this? Thank you!
Click to expand...
I would think moly would make the bullet have less friction. Then the pressure wouldn't build in the case. I like the powder to burn mostly in the case. It seems to give a better form. Matt
 
Though I don't use moly on my bullets, I do use hBN. I even use it on my fireforming loads and there has never been a naked bullet shot down my current barrel. I have had zero issues with my brass forming properly into Dasher and that includes using both the false shoulder and jam methods! I have only used N140 and R15 in my fireforming loads.
 
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I've used 30.0gr Varget in a virgin Lapua 6BR case and roughly 0.030" jam with a 105 Amax...worked just fine with -450s and produced a crisp shoulder. 29.0gr Varget and same gave me a slight radius on the shoulder/body junction.
 
A lot of guys have told me they were getting a lot of misfires doing this. I have not had a misfire yet and I get better expansion on the brass.

Joe Salt
 
Ray tried Hydroforming it still didn't do as nice a job, and no mess to clean. Plus its a lot faster, and you can break in your barrel at the same time.

Joe Salt
 
Did not want to use my good competition barrel for fire forming. So switched to a well used 6 dasher barrel. Tried the jamming method (as false shoulder method takes extra steps).
Had 50% miss firers. Although the round was jammed in there, with the fire pin strike, the entire case would move forward, and I would end up with a dented primer.
From now on I use the false should method.
 
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