Fire Forming Cases with COW

[onelastshot]

I know there was a recent article on this, I just can't find it. Anyway, I picked up my 6mm AI yesterday, I had a mauser 98 action re-barreled by McGowen with a heavy barrel Shilen 7 contour. The stock will be black walnut with a 5/8 section of bird's eye maple down the center.
I'm taking pictures as I go, the laminating is done, I've rough cut the dimensions and today I started hollowing out the center for the magazine. My first attempt at making a stock so I'm going to take it slow.

Anyway, I'd like to avoid using up 10-20 percent of my barrel life fire forming the 6mm brass to 6mm AI. I remember someone make mention that a faster burning powder such as bulls eye or Unique should be used. I have some older Hercules Unique and a can of Blue Dot I would like to use if possible. If someone could tell me how many grains of either powder to use I would appreciate it.

Thanks.

 

[shooter63]

go to 243 on home pg. & scroll down to the blue article lol shooter63

 

[onelastshot]

go to 243 on home pg. & scroll down to the blue article lol shooter63

Thanks for responding. I also did some more searching and found this link http://www.angelfire.com/sd/6mmackley/fireforming.html

The article is straightforward and easy to follow. It sounds like the only downside to this process is it tends to make quite a mess; I just might stop over at my brother's house next week while he's at work and use his family room, I owe him a favor or two!

 

[Ackman]

You want to waste time and components, use COW. Fireform with bullets. Starting at about top end for the std. 6mm, treat it like any other cartridge and work up until you find best accuracy. That's your "fireform" load. It'll be a whole bunch faster than the std. 6mm. It'll also be close to the same powder charge and about as fast as with formed cases. In other words, it's not a "fireforming" load, it's an everyday shooting/hunting load. You won't be "using up 10-20% of barrel life..."

Writing an article doesn't mean someone knows.

 

[Gary in MD]

I agree with Ackman! My "fireform" load in my 6mmAI is pushing the 75gr Hornady @ 3600 fps with groups under 1/2". This is only a 175 fps slower than my normal hunting load. I'm using a max charge of powder for the standard 6mm rem. The cases are always fully formed and the loads are pretty hard on the groundhogs. Eat your breakfast cereal and then go shooting...
Gary

 

[TC260]

I say try it and learn a new technique. If you don't like it go back to using bullets. I find that sometimes it makes sense to do one and sometimes the other.

 

[BoydAllen]

A little fire forming story:
Yesterday, I went down to the Visalia range to visit with some shooters that are shooting a benchrest match that runs both days of this weekend (today and tomorrow). One of the fellows, (world record holder) was fire forming some of the new Norma 6PPC brass, that I know to be a very loose fit. I have some. The case "headspace" is around .010 short of my chamber dimension, and the diameter at the shoulder is about.0025 smaller than a fired case. With a crazy light load of old 8208, he shot two five shot groups, in conditions that were a long way from calm, that, looking through the scope, were indistinguishable from the hole made by a single bullet. He probably had his bullets seated a specific amount into the lands. Having seen this, and other similar examples, I would say that it is entirely possible that if you do a careful workup. that you might find a fire forming load that is very accurate, and given your caliber, produces a velocity that could be quite useful. BTW, another fine shooter, who has a lot of experience with this brass, told me that for new cases, he just loads his normal load and it works fine. I realize that you can't do that, but I thought that you might find that interesting. When I was first firing these cases, I was measuring case shoulder location, and found that it actually takes a fairly stout load to bring them out to chamber dimension. If I buy some more, I will take that course. The accuracy was actually pretty good, once I got the seating depth right. I think that that is often an under explored variable. I think that shooters tend to spend too much time on powder charge, and too little on fine adjustment of seating depth. Recently, I have decided that I have been operating on the basis of some untested assumptions. The good news is that I may have stumbled onto something that works better, thanks to a friend.

 

[TC260]

Wayne, what were you using to plug the cases? I've done a fair amount COW fireforming, mostly for high power hunting handguns were I don't really want to subject myself to long fireforming sessions with bullets. Using instant COW and some RCBS bullet lube smeared over the top to hold everything in I haven't noticed any buildup problems. On firing everything essentially disinegrates. No mess and clean-up is very easy.

On youtube and other sources I see recommendations for candle wax, bar soap, etc. to plug cases and I'm wondering if something similar was used maybe that lead to the build-up problems?

 

[DennisH]

I just might stop over at my brother's house next week while he's at work and use his family room, I owe him a favor or two!

Send them to me, I will gladly do them for you, I need to visit my mother in law!

 

[Nodak7mm]

I just might stop over at my brother's house next week while he's at work and use his family room, I owe him a favor or two!

Send them to me, I will gladly do them for you, I need to visit my mother in law!

Remember you can do this with MOM too, not just COW....

Rod

 

[ChuckMiller]

If your going to hunt with them just work up a load that gives you acceptable accuracy and forms the case. If your building this for long range accuracy, ie 500yd ballon shoots or the like your wasting barrel life and components. I have a 6mmAI, Krieger 1-10 and fireforming with bullets gives me between .75-1.00MOA, enough to guarantee you last place at most long range fun shoots. My fireforming technique is to load 10grs of Unique, dump COW until it overflows, take a piece of toilet paper and wedge it into the neck compressing the COW. No need for wax, don't need anything separting the powder or COW. I fireform in the garage into this contraption, basically a plastic trashcan that the lid is screwed down with a hole cut in the top. I used some cheap foam rubber to muffle the report. Standing out at the street you can barely hear it. It lets me do it at my convenience, works great and I can do one at a time until I get the results I want. I clean out the bore after every 15 rounds and once I'm done I give it good cleaning. I don't use this on small cases as fireforming accuracy seems to be pretty close but on large overbore cases I do.

 

[onelastshot]

Thanks everyone for the responses and advise. Just for experience, I think I'll try one batch of COW and see what kind of results I get. If anyone would like to help me decorate my brother's house with this experiment, let me know. And, if you really have your heart set on an afternoon of shooting at your mother-in-laws, you just might be able to talk me into joining you.

 

[lpreddick]

i use the cow method and fire into a large bale of fire resistent attic insulation...do this in my shop and the noise is whhhuuuummmmmpppp.

 

[DennisH]

And, if you really have your heart set on an afternoon of shooting at your mother-in-laws, you just might be able to talk me into joining you.

I will pay your expenses to make the trip! :

A roll of fiberglass insulation or a bale of hay will work. With the bale of hay, you will have to have a water hose running and stick it in the hole immediately. A bale was there one day and I tried it, it did the job. Shooting in a bale of had act's like a silencer, it will take the boom out of the shot! I shot my 223 AR into it and all I could hear was the bolt action and "blup"!

 

[wapiti25]

Caution, some have had a fire in the container or bale of hay.

 

[lpreddick]

no worries about fire in my bale of fireresistent insulation. i actually put flame to the stuff and tried to get it to catch fire. it only smoldered for as long as the flame was present. remove the flame and the smoldering went out! very safe stuff and my bale has been used for two years. one has to duct tape the seams after awhile since pressure does buldge the bale. every so often i'll beat the sides to redistribute the material but it seems to work best with a a little cavity in the center. a don't do as i do...i have fired a full charge 22-250 hollow point varmint bullet with the material very evenly distributed and the bullet lodged under the backside duct tape...one did however exit lodging in the 2x8 pine board. the sound was a little bit louder than when cowforming. don't try this at home, unless...be careful.

 

[Ackman]

I mostly agree with with others, load and shoot, I don't agree to load it too hot, you can stretch your brass,

Don't know what you mean by "too hot".......fireform loads that are past max for the parent cartridge, aren't too hot. And with a properly cut chamber brass will NOT stretch when fireforming.

 

[bigedp51]

bozo699

Dear (expletive deleted) old buddy, I have just one question.

How many COW hot loads have you ever seen...............really?

 

[bozo699]

bozo699

Dear (expletive deleted) old buddy, I have just one question.

How many COW hot loads have you ever seen...............really?

Biged,
I fell off my chair and onto the floor LMAO!! the wife thought I was having a seizure,...only you my friend :
Wayne.

 

[dennisinaz]

I don't declare myself to be an expert on it but I will add my 2 cents. I had an Ultra Light Arms 257AI that I bought from John Barsness. I liked the gun but didn't like fireforming. The whippy little barrel heated up with one or two shots. It was a PITA to fireform brass. I finally sold it.

Fast forward a decade. I have a 260AI and I decided to FF with COW. I use 15 grains of unique. fill to top with COW and jam and ivory soap bar over it to seal it off.

My chamber is such that a new piece of brass is a snug fit when closing the bolt. I fan fire about 20 rounds before it is too warm. I then pour ice water over the barrel, wipe it off and fire 15 more. In just a few minutes I have 100 pieces of perfectly formed brass. I think it is silly to waste time and components with a load that you will never use other than fierforming.

I did the same thing with a 7WSM using 300 WSM brass necked down. (no such thing as good 7 WSM brass). I used 18 grains of unique and the same procedure.

Wish I had tried this in the ULA days.

Some may cringe at the water trick but I take a cooler of ice water to the range and just hose the barrel off. With a SS barrel, I don't worry a bit, with a CM barrel, I make sure I blow the water out from the barrel channel or remove stock when I get home.

practicing or working up loads when it is 100 degrees is not very practical without doing this. A CO2 set up would be likely better but not nearly as convenient!