How to Fire-Form Brass without Bullets
Many of our Forum members shoot an “improved” 6mmBR cartridge. This might be a 30°-shoulder 6mm BRX, or a 40°-shoulder 6mm Dasher, or the 6mm BRDX, which is very similar to the Dasher, but with a slightly longer neck. This Editor shoots a 6mm BRDX and has found it very accurate, and maybe a bit easier to fire-form than a standard Dasher. Speaking of fire-forming, in our Shooters’ Forum, we often see questions about fire-forming BRX/Dasher brass. For those who need a large number of BRX or Dasher cases, one option to consider is using pistol powder in a dedicated fire-forming barrel. Here’s an explanation of how this process can work.
Forum member Skeeter has a 6mm Dasher falling block varmint rifle. The Dasher case is based on the 6mmBR Norma cartridge with the shoulder blown forward about 0.100″ and out to 40°. This gives the Dasher roughly 3.5 grains added capacity compared to the standard 6BR.
A few seasons back, Skeeter needed to form 300 cases for varmint holiday. Skeeter decided to fire-form his brass without bullets. This method avoids barrel wear and saves on components. There are various ways to do this, but Skeeter chose a method using pistol/shotgun powder, some tissue to hold the powder in place, Cream of Wheat filled to within an 1/8″ of top of the neck, and a “plug” of tissue paper to hold it all in place. Shown below are cases filled with a pistol/shotgun powder charge topped with Cream of Wheat and then a tissue paper plug.
To ensure the case headspaced firmly in his Dasher chamber, Skeeter created a “false shoulder” where the new neck-shoulder junction would be after fire-forming. After chamfering his case mouths, Skeeter necked up all his cases with a 0.257″ mandrel (one caliber oversized). Then he used a bushing neck-sizing die to bring the top half of the neck back down to 0.267″ to fit his 0.269″ chamber. The photo below shows how the false shoulder is created.
After creating the false shoulder, Skeeter chambered the cases in his rifle to ensure he could close the bolt and that he had a good “crush fit” on the false shoulder, ensuring proper headspace. All went well.
The next step was determining the optimal load of pistol powder. Among a variety of powders available, Skeeter chose Hodgdon Titewad as it is relatively inexpensive and burns clean. The goal was to find just the right amount of Titewad that would blow the shoulder forward sufficiently. Skeeter wanted to minimize the amount of powder used and work at a pressure that was safe for his falling block action.
Working incrementally, Skeeter started at 5.0 grains of Titewad, working up in 0.5 grain increments. As you can see, the 5.0 grain charge blew the shoulder forward, but left it a hemispherical shape. At about 7.0 grains of Titewad, the edge of the shoulder and case body was shaping up. Skeeter decided that 8.5 grains of Titewad was the “sweet spot”. He tried higher charges, but the shoulder didn’t really form up any better. It will take another firing or two, with a normal match load of rifle powder and a bullet seated, to really sharpen up the shoulders. Be sure to click on the “View Larger Image” link to get a good view of the cases.
The process proved to be a success. Skeeter now has hundreds of fire-formed Dasher cases and he hasn’t had to put one bullet through his nice, new match-grade barrel. The “bulletless” Cream of Wheat method allowed him to fire-form in a tight-necked barrel without neck-turning the brass first. The only step now remaining is to turn the newly Dasher-length necks down about .0025″ to fit his 0.269″ chamber. (To have no-turn necks he would need an 0.271″ or 0.272″ chamber).
Skeeter didn’t lose a single case: “As for the fire-forming loads, I had zero split cases and no signs of pressure in 325 cases fire-formed. Nor did I have any misfires or any that disbursed COW into the action of the firearm. So the COW method really worked out great for me and saved me a lot of money in powder and bullets.”
Skeeter did have a fire-forming barrel, but it was reamed with a .269 chamber like his 10-twist Krieger “good” barrel. If he fire-formed with bullets, he would have to turn all 300 necks to .267″ BEFORE fire-forming so that loaded rounds would fit in the chamber. Judging just how far to turn is problematic. There’s no need to turn the lower part of the neck that will eventually become shoulder–but how far down the neck to turn is the issue. By fire-forming without bullets now he only has to turn about half the original neck length, and he knows exactly how far to go.
Similar Posts:
- Fire-Forming Dasher Brass with Pistol Powder
- How to Fire-Form Dasher and BRX Brass without Bullets
- Forming Dasher Cases with Pistol Powder
- TECH TIP: Form Improved Cases with Hydraulic Forming Die
- 6mm Dasher Basics — Bob Hoppe Talks about Loads
Tags: 6mmbr, COW, Cream of Wheat, Dasher, False Shoulder, Fire-Form, Grits, Skeeter, Titewad
I have fire formed a lot of 6PPC cases (from .220 Russian) using pistol powder (usually Bullseye) without filler. I stuff a small square (about 3/4″) of paper towel in the case necks. It works just fine. I will say that I have no experience doing this to form cases such as the Dasher, where the shoulder is moved forward by a significant amount…but I do not see any reason why it would not work. One caution about using Cream-o- Wheat. I have heard of deposits inside of cases, on the underside of the shoulder, no experience, just a report from a credible source. If I were going to try that method, I would take the extra time it took to use bent wire to check that area after fire forming.
Excellent option!
2016 had me building a 7mm wildcat called 284INCH that uses 308 brass. Needed to FF cases from Lapua PALMA brass (previously used for Palma shooting) & with no COW in my house I used plain corn meal.
I’ll try tissue paper wad as suggested for the next batch! Corn meal works fine but without extra filler it’ll be less hassle.
Initially used the CoW method using a take-off barrel chambered with the exact reamer, but found that simply forming the brass with a bullet, with the false shoulder, in my primary barrel, still shot remarkably well. In fact, coached an acquaintance in a 1000yd sling match while he fire-formed my brass in that rifle. It is the only 200 score he has ever fired before or since.
I have (3) 6.5cm complete guns. Two Kimbers and one new Custom build 6.5cm with a Shilen premium grade barrel for LR.
I also used some premium Eagle Eye loads in the Kimbers with Alpha brass when I was setting them up to hunt. I want to use the 150 rounds of Eagle eye I fired through the Kimbers and now load it for the new rifle. To make the brass conform to the new rifle chamber without loading up complete charged cartridges , can I just pop a primer in uncharged brass and get it a little tighter in the new gun chamber?
I dont shoot competitively. But the new gun is doing .5moa when I’m doing everything right and I dont want to blow 150 rounds through this new gun just to fire form the same caliber.