issues with COW method of fireforming

[brian1]

I have mostly fireformed using either the end result bullet or cheap stuff if I have it laying around. I've also tried using the Cream Of Wheat method I've read so much about. I've always been rather leery of gunking up my chamber and bore with burned-on wheat residue. I haven't seen signs of this, but it seems it could happen, so I've only done the COW method a few times. I did a couple .219 Donaldson Wasp from 25-35 cases, and they seemed to come out OK, but then I went back to using bullets, mainly because I didn't want to gunk up the barrel.

The last time I tried it, a few days ago, forming 6.5-06 Imp 40 from 270 Win, using 4.5 gn Tite Group, it fireformed the case OK, but the case, especially around the shoulder, was packed with hardened COW after firing. I scraped on it for awhile with a dental pick, then ended up soaking it in hot water for awhile, and finally got all the junk out of there after quite a bit of work. That was the end of COW for me..

Have you folks seen this? Did I do it wrong? I put the powder in, then filled it to the neck with COW, then stuffed a bit of paper towel in on top of the COW, and fired it. Was it because of the sharp shoulder?

I'd rather not waste bullets fireforming, but I'm now even more leery of the COW method. In Ken Howell's book, "Designing and Forming Cartridges", he makes extensive references to using the COW method for all the fireforming he talks about.

[cwtebay]

I have used the COW method for thousands of pieces of brass. I generally use 3 grains of BR5 (I have used unique, red dot, blue dot, etc. in the past - just happened upon a few kegs of BR5 on the cheap) covered with cotton batting, case full of COW, covered by same cotton batting - shoot them in the intended rifle (generally at night, in the yard - just to keep the neighbour wondering). I haven't encountered what you described unless the double wadding is left out - the over powder wadding seems to keep the carbohydrates in the cereal from carmelizing in the brass. As a side note; check the chamber of your rifle. If it did that inside of the brass, it can happen in the rifle also. I have heard of fellas cussing COW because it is dirty, can't say I've ever had that problem either.

Cheers!

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[upnorthwis]

Might depend on caliber and hardness of brass. I've had great success turning softened 8mm Lebel in to .41 Swiss. Used 10 gr. 231 with as much COW as I could pack in, then put more in and packed that in too. No wad either. If there was any residue left in brass, I never noticed it.

[mac60]

I always separate the powder from the cow with 1/4 sheet of TP. Fill it to the mouth then cap it off by pushing the mouth into a block of parrafin.

[BS2]

Never had that problem, are you using plain COW, not some sugared type?

Are your cases dry?

I use a 380 case of HS6, works great.

[15meter]

My suspicion the problem is the COW directly on the powder, I've done a fair number of fire formed cases and have never had what you are describing.

If you're brave enough, try it one more time, but with a wad on top of the powder.

[brian1]

Cases are dry. I could try it again sometime, using a wad between the powder and filler. As far as sugar in the COW, I'm not sure. That sure would not be good. I'm trying now to find the original container I got it from before putting it in a Tupperware container. It was just something my wife had laying around. I'll try to find the original box in our paper recycling bin.

ITMT, I've fireformed 100 cases using bullets and found that, even during fireforming, the accuracy and performance is very good.

[Chill Wills]

This might be apples and oranges.
I form 40 cal brass cases from 30-40 Krag
It becomes the 40 Krag or really it is the black powder 40-60 Maynard

6 grains of Clays or Bullseye and a case lightly filled to the top with CORN MEAL and a small plug of bullet lube in the mouth to keep everything in. Smells like cornbread when fireforming.
Makes great cases in one try. Trim the mouth and done.

[garandsrus]

I have only used COW to blow out a case shoulder and form a straight case. I don’t think I would use COW with a bottle neck case, where the intent was to keep a bottleneck.

When I have formed cases with smaller necks, I resize to create a false shoulder and then shoot a light load to form the case.

[sharps4590]

I got completely away from COW and now use corn cob tumbling media. Forms the cases better than COW, IMO, and I do believe it cleans and polishes the bore. A side benefit is, if you are forming cases during the summer, the media makes for an excellent upland load for wasps, hornets, wood borers and the like.

[brian1]

I have only used COW to blow out a case shoulder and form a straight case. I don’t think I would use COW with a bottle neck case, where the intent was to keep a bottleneck.

When I have formed cases with smaller necks, I resize to create a false shoulder and then shoot a light load to form the case.
Maybe that's the problem. It has a significant bottleneck, and the fireforming makes it an even sharper bottleneck (40 degree). All the hardened COW was around the shoulder, with a hole through it through the neck.

[Chill Wills]

Maybe that's the problem. It has a significant bottleneck, and the fireforming makes it an even sharper bottleneck (40 degree). All the hardened COW was around the shoulder, with a hole through it through the neck.

There is no way to know what the pressures are. It would be good to be cautious. I found my powder charge by working up and stopping when I got to a fully blown out case and no more.

I like that someone else noticed the shotgun effect. Some years ago when my son was 14, I had 50 cases of 30-40 Krag brass to make up into 40-60 Maynard and took them camping with us. My son had more fun with the task of fireforming the cases and blasting "stuff" than he did shooting the other assorted firearms we had with us. Bugs and pine cones were running scared.

[ipopum]

I also use cornmeal . Mine comes from the plant that makes ethanol and sells the ground portion for livestock feed.

You might want to try white rice also. I think that the wad to separate the powder from the cow is important.

[15meter]

I used the corn nibs/weed seeds from under a grain dryer for years until my buddy quit drying his own corn. Using corn meal now, don't have cream of wheat.

I've done a bunch of 30-30 into 38-55's, and I've done bottle neck cases but with this geezer CRS thing going can't remember which ones. The only problem I've ever had was lop-sided 38-55 when fired horizontally. When fired vertically they blew out perfectly.

Depending on the case, sometimes it is easier to fire form than re-form cases using dies. Cheap too, usually a smaller charge of Unique and no boolit cost. Luckily I can fire-form cases in my backyard, saves me a trip to the rifle range.

And I have a whole bunch of 40+ year old pistol primer/mystery primers--you know the kind--handed to you at the gun club in a glass!!!! jar.

"You reload don't you? Can you use these?" kind of primers.

They make great fire-forming primers. Doubt if I'll blow up a gun using mystery magnum and or pistol primers for fire-forming. Not too worried about getting corrosive/mercuric primers.

Been a looong time since corrosive primers were out there and even longer since mercuric primers were on the market.

YMMV

[BS2]

I have only used COW to blow out a case shoulder and form a straight case. I don’t think I would use COW with a bottle neck case, where the intent was to keep a bottleneck.

When I have formed cases with smaller necks, I resize to create a false shoulder and then shoot a light load to form the case.

I do straight walls also.

[lar45]

The only thing I can get here locally is Grits.
I use a 1/4 sheet of TP on top of the powder to separate the powder from the grits. I use a punch to tamp the Powder down good and tight.
I have a 1000 pieces of FC 30-30 and have been blowing them out straight for 375Win cases.
After the powder and TP are in good and tight, I scoop the case full of Grits and use the same punch to tamp it down good and tight. Finally I put another 1/4 sheet of TP on top and pack it down.
I fire form in my TC Contender, and hold the pistol straight down so the brass will be centered while it's being formed.

[15meter]

Off topic, I use two Redding powder measures when loading for fireforming.

One to drop powder, second one to drop the corn meal. Works great and speeds up the operation considerably.

[GhostHawk]

Cornmeal here also. I bought a container for buffer for buckshot loads so it is always handy.

I've had zero problems with cornmeal in cases or barrels. It all seems to go out in the blast. Biodegradeable, and food for critters that find it.

I converted some .303 HXP to .410 brass shells and the cornmeal worked great. Moderate loads of Red Dot used for the process. I dropped a .40 cal cast on top of mine instead of wad/wax and got great fillout in the neck.

[shaggy357]

I have over 10,000 rounds of formed brass in the reloading room. 6, 6.5, and 7 TCU are about 2000 of the loaded rounds and they have to be made. Out of all of my “formed” brass exactly 100 were made with the COW method. I did not like the mess, and the time spent blowing off the rounds felt like a waste of time. Some shoulders didn't form all the way because pressures were not consistent.. Not saying it dont work. Saying it isnt my idea of keeping it fun...although i didn't shoot at bugs...

Years ago, i read P O Ackley’s books on his improved cases. Each of his improved cases were designed so the parent case could be fired, with proper headspacing, in the improved chamber. On that premise, i have figured out a way to form the parent cases by sizing them to properly headspace in the chamber i want to form them in. My 260 and 7-08 brass are formed from 308 match brass. My 25-06, 270, and 280 brass are formed from -06 match brass. A moderate book load, for target shooting, hunting, etc, forms the cases very well. Had my XP-100 in 260 hitting a gong at 1000 yards with loads that were forming the shoulder. It took several shots at 300, and then quite a few more to walk it in, but once on at 1000, it was fun trying to hit that gong...much funner than blowing COW and tissue all over the place.

My $.02

[MOA]

This might be apples and oranges.
I form 40 cal brass cases from 30-40 Krag
It becomes the 40 Krag or really it is the black powder 40-60 Maynard

6 grains of Clays or Bullseye and a case lightly filled to the top with CORN MEAL and a small plug of bullet lube in the mouth to keep everything in. Smells like cornbread when fireforming.
Makes great cases in one try. Trim the mouth and done.


Chill, this is what I'm doing now with a handy rifle. I'm blowing out my krag cases for the Maynard. My question is what mold are you using for your boolit? And, what are you shooting your Maynard cartridge in?

[HangFireW8]

I had the same problems with CoW- caking, left in barrel and chamber, incomplete shoulders. I was forming 257RAI. After more experiments I settled on a full house load of medium burn rate powder under a midweight jword, seated to the lands, and oiling the neck and shoulder lightly to facilitate forming without stretch.