A rather sinple question Ihope about the COW method of fire forming.. Coes the size of the case effect how much powder you need to use. I read where a guy sizing 6 Dasher brass used 8.5 grains of Tite Group. I am sizing 338 Edge brass do I need more Tite Group or the same charge.
A question about the COW method and case size.
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I typically use 1/3 the amount of a typical full power load.
Lapuatom
Well-Known Member
I used 10gr Unique to form 240 Gibbs from 270 cases. This gives about 95% form, first full power load gives you the rest.
Lapuatom
Well-Known Member
I use 10gr Unique to fireform 240Gibbs cases from 270 cases. This gives about 95% then the first full powered load gives you the final product.
I've been using the 1/3 rule to fire form wildcat cartridges for 40 years. My powder of choice is green dot.
Can't remember how all these powders are burn rate wise. I will asume the faster the powder the less you will need need is that safe to say. Will my loads with one nineth of normal load be enough to establish any kind of a useable shoulder. That is with me using Tite Group or should I start over. I need to push the shoulder at the neck junction .020.
Long story I found the 338 Edge dies had a tapered expander ball just not in the neck die.
Long story I found the 338 Edge dies had a tapered expander ball just not in the neck die.
The powders used for this are usually fast burning pistol or shotgun powders.
LongBomber
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In my edge ai I used 19gr of green dot. Shoulders very close to fully formed.
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15gr of Unique worked really well forming .375-06 from .30-06 and 6.5 x 280AI from .270Win brass.
Ed
Ed
How Unigue?
nksmfamjp
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Thread 'COW Fireforming recipe'
https://www.longrangehunting.com/threads/cow-fireforming-recipe.303247/
it is in the article linked to in this thread.
The quick recipe is fill a case with your forming powder. Weigh the powder. Start with 1/10.
Example: 300 Sherman - 57.8gr of Titegroup fit in my case. 1/10 is 6 gr. I wound up using 11gr after some testing which showed that was the minimum charge that formed a nice Ackley shoulder.
https://www.longrangehunting.com/threads/cow-fireforming-recipe.303247/
it is in the article linked to in this thread.
The quick recipe is fill a case with your forming powder. Weigh the powder. Start with 1/10.
Example: 300 Sherman - 57.8gr of Titegroup fit in my case. 1/10 is 6 gr. I wound up using 11gr after some testing which showed that was the minimum charge that formed a nice Ackley shoulder.
Just an alternate perspective to consider: For any cartridge that does not head space on the shoulder, so rimmed or belted cartridges, COW fire forming is a waste of powder, primers and Cream Of Wheat. In addition, AI cartridges were specifically designed so you can shoot regular loads in them and end up with fire formed AI brass so not a lot of benefit to COW forming those either.
If the cartridge you are working with do space off the shoulder and aren't an AI, just create a false shoulder on the neck. Fire forming loads will shoot almost as good as post formed so you might as well get the benefit of the extra shooting in if you are going to burn up valuable primers.
If the cartridge you are working with do space off the shoulder and aren't an AI, just create a false shoulder on the neck. Fire forming loads will shoot almost as good as post formed so you might as well get the benefit of the extra shooting in if you are going to burn up valuable primers.
