COW fire forming

[Alex Wheeler]

- I don't believe that the C.O.W. is "pushing brass forward" any more than what Toilet-Paper or a cotton ball is, and I believe that the pressure being built by the explosive force of the powder is what causes the brass to form to the chamber. (Also a reason that smaller weights of relatively quick burning powder is used in this process). - I've used the old Hercules Bullseye powder (back before is was Alliant) and a small wad of toilet paper to hold the powder charge at the rear of the case without any plug of wax & formed some brass in that manner.

The pressure of the explosion is behind the projectile. So if you cap the neck with a little paper or wax and form the brass I think it would work well. If your pouring cow directly on top of the powder then your not forming with the pressure of explosion but rather a compressed material being forced through a neck.

 

[LA50SHOOTER]

The pressure of the explosion is behind the projectile. So if you cap the neck with a little paper or wax and form the brass I think it would work well. If your pouring cow directly on top of the powder then your not forming with the pressure of explosion but rather a compressed material being forced through a neck.

Alex, not to turn this into a "marathon" thread, But, - pressure is being built regardless when fast burning powder is used. A piece of toilet-paper (& C.O.W. offers only slightly more) offers very little to almost no resistance in the grand scheme of things compared to a bullet or a wax plug, peak pressure is built in the "point milliseconds" (0.25 milliseconds to reach peak pressure) range and that pressure is expansion of gas through the burning of the powder. (The T-P can be just something to keep the powder charge at the bottom of the case so the primer detonates it).
The rate of gas expansion far exceeds the unused (by powder) case capacity and bore diameter and pushes the brass out to form to the chamber. - My point is, Pressure of Gas and its Expansion are what is forming the brass whether C.O.W. or anything else is used on top of it. - Of course the more we offer resistance (through use of a bullet or a wax plug or whatever)the more efficient the forming operation can become as well as predictability as to how well the brass will form and less propellant will also be required to achieve the intended result.

 

[LA50SHOOTER]

And just for the sake of testing, I'm going to run a test. And use Bullseye as the powder & a Magnum primer.
I'll use New unformed brass and do the following:
A). Brass case with JUST powder, Gun kept barrel up so the powder sits in the bottom of the case, I'll vary charge in safe increments and run 3 or 4 tests
B). Same as "A" but with a small amount of T-P
C) . Same as "B" but with a wax plug

I'm betting every one of those "tests" will form brass, and of course C will take less than B, and B less than A.

 

[Dusty Stevens]

Dont use cow period. Its one of the fastest ways to blow up a gun if your case fill normally is less than 95 or so

 

[Uncle Ed]

I prefer rifle powder in my rifle and breakfast cereal in a bowl.
Just me of course

But some cereals are shot from guns.

 

[Ned Ludd]

...I do not like or recommend cream of wheat...

I feel certain this would change if you tried the "Maple Brown Sugar"...it is very delicious.


In all seriousness, I have never quite understood the COW (or similar) approaches to fire-forming brass. That's a fair amount of effort for no real benefit or useful information gained other than prepping the brass. Over the years, I have had many question that fact that I do preliminary load workups in virgin brass. I do this knowing that the load parameters will have to be tweeked once the brass is fire-formed. Nonetheless, I believe you can gain useful information about how a particular barrel behaves AND obtain fire-formed brass AND lap the barrel at the same time using this approach. Obviously, a judicious application of this approach is beneficial, as you don't want to wear your barrel out simply fire-forming virgin brass, but that's also why it's useful to keep an older barrel around for fire-forming purposes.

 

[LA50SHOOTER]

Dont use cow period. Its one of the fastest ways to blow up a gun if your case fill normally is less than 95 or so

That's Simply NOT True at All - I'm calling B.S. on that - I know better.

 

[Dusty Stevens]

That's Simply NOT True at All -

You havent done much of it then. It gets baked in under the neck and creates severe pressure situations taking up case capacity. Its even been documented on here one of the 432 times its been brought up

 

[LA50SHOOTER]

You havent done much of it then. It gets baked in under the neck and creates severe pressure situations taking up case capacity. Its even been documented on here one of the 432 times its been brought up

To that I say "You have to be Smarter than the Damn Iron" then - If someone isn't smart enough to check for that then maybe they have trouble doing other things in life.

And for you Sir, Who are YOU to Question how much of what I've done ?? - You don't know me & I don't know you. - You have No Idea what my professional or formal training is and on what subjects or my level of experience is either, So go Pass your Judgement and Conjecture on someone who you really know, Like maybe yourself before you go into print at me.

 

[Dusty Stevens]

To that I say "You have to be Smarter than the Damn Iron" then - If someone isn't smart enough to check for that then maybe they have trouble doing other things in life.

And for you Sir, Who are YOU to Question how much of what I've done ?? - You don't know me & I don't know you. - You have No Idea what my professional or formal training is and on what subjects or my level of experience is either, So go Pass your Judgement and Conjecture on someone who you really know, Like maybe yourself before you go into print at me.

Sometimes you gotta know your audience. To give potentially dangerous advice to the masses?... well i try to not let that happen. You keep doing what you do because obviously youre smarter than the iron youre working with- congratulations.

 

[Uncle Ed]

No COW at Sierra.................Holy COW Batman!.....Could COW be Fake News.

Reloading 101: Fireforming Cases
https://sierrabulletsblog.com/2016/09/14/reloading-101-fireforming-cases/

 

[gunsandgunsmithing]

The pressure of the explosion is behind the projectile. So if you cap the neck with a little paper or wax and form the brass I think it would work well. If your pouring cow directly on top of the powder then your not forming with the pressure of explosion but rather a compressed material being forced through a neck.

I won't get into specific loads I've used but I actually think that tissue paper or cotton works very well when used with a powder that is slow enough to give decent fill and fast enough to build the needed pressure to form the case. I know I'm there when the case stops getting shorter and starts getting longer. I typically use a dedicated ff barrel and lightly lube the cases when I use this method. So, My results and what I've found to work seem to agree with what you've said on this. I will say that I've used Hodgdon Universal to form 30 grendel brass from 6.5 grendel many, many times with good success, although I don't always use this method, as well as many 30br's.

I think the benefits are simple though...a case that's very near completely formed and very straight and uniform necks. I seem to use whatever method I'm in the mood for, as there is more than one way to skin this cat. FWIW, using my process, I think ff'ing is the best possible way to do the little forming and neck expanding of this case. I've used it for other cases with equally good results.

I do agree with you about controlling where the brass flows from. You don't want the case being shoved forward and no way for it to firmly seat against the bolt face. Again, more than one way to ensure this too. A false shoulder is best, particularly when blowing the shoulder forward to form a dasher or similar. But I doubt it would matter with a bra, as long as you lightly lube the case or chamber for a light crush. There is very little thrust this way vs with a bullet. --M

 

[Boyd L.]

Interesting thread....
I’ve used every method (except hydroforming) described here. Frankly the method of forming takes a backseat to finding some quality brass from which to form cases. The Winchester factory .257 Roberts loads I formed with 10 years ago turned out to be the best I would use (so far). About 5 years ago I began a search to replace the Winchester brass and discovered that it couldn’t be found. I thought I’d even try Remington, though initial experiences found it to be less consistent than Winchester, but alas none was found. Even 7x57 brass was difficult to obtain. I finally found some Hornady .275 Rigby brass to neck down/form. Accuracy isn’t quite what the Winchester gave. Still no Winchester available through my sources. Found a new bag of Remington and long seating a Speer 120 is producing a series of cases with a ring near the mid point of the case. I haven’t sectioned one yet to evaluate but it’s a great example of needing better brass. I’m flexible on forming method....just need some brass. Maybe Prvi Partizan 7x57 or Nosler next.

 

[Ledd Slinger]

The best results I had when testing COW was when I stuffed a wad of tissue in the neck very tight. Created more back pressure on the case (that could be felt by extra recoil on the rifle) and formed cases much better than using wax in the neck. Even better yet was filling the case completely with Unique powder, stuffing the neck with tissue, and not using any COW. No mess in the bore plus gave me sharper shoulders and better body dimensions. Tho still not quite as consistent or good as forming with bullets.

I've never tried hydro forming cases. Might have a die cut with one of my reamers and give that a go just to see how well it works

 

[Don_Parsons]

I don't know what Rifle Kow is, but we have a pasture full of Kows that don't shoot guns.

If a person chooses to end up with properly sized cases that fit the chamber like a glove, then why not use a very thin layer of silicone spray and clean chamber to fire-form the cases.

And a person can do some target shooting at the same time.

Two Kows with 1 stone metaphorically speaking that is.

Make up some pet loads bellow max pressure, a quick thin coat of silicone on the cases,,, and you'll have fully formed cases along with some nice vertical/ horizontal groups down range. Ha.

Of course there will be the odd fly'ers.

We don't have time to do things the complicated way since we are shooting folks.

Some times we attend shooting competions, general plinking matches, long range stuff and Hunting.

Buy 400 to 600 peaces of Lapua brass for each rifle, then slowly shoot it out till the brass and barrel is garbage,,, once the barrel is shot out,,, the brass is pretty much pooched by then.

Yuppers, to much work put into fire forming brass for us when we can get at it the easy way.

I'm off to the pastures to feed the Kows, hopefully the Coyotes are on the run so I can fire form some more brass for the 2019 season coming up.

Don

 

[ARK]

Sounds good Don, if only my barrel would have unlimited number of rounds I can fire before it turns into expensive stainless conversational piece...

 

[LA50SHOOTER]

What's the gram to grain conversion rate on that cereal ?
Curious

1 Gram = 15.4324 Grains (Mass) as per Google Search.

 

[Don_Parsons]

A pinch of Salt Peter, a dab of charcoal, and a sniff of sulfur to blend in with the cotton balls.

Hey,,, wait a minute,,, that mixture sounds alot like Black Powder .Ha.

Might need to tap it kool on the first peaces of brass.

Nothing like fire forming the brass with some charge behind the bullet.

 

[Ccrider]

After reading this post, all I could conclude is that there is more than one way to skin this cat.

I like the idea of hydroforming and have a hydroform die for my Dasher.

But, if this is the preferred method, why am I not able to find post where 6ppc shooters are hydroforming 220 Russian to 6ppc? Seem like they all seem to fireform. Or, am I missing something?

 

[fredo]

Interesting debate.
Where I can see using breakfast to form certain cases holds merit, I break it down to time/cost analysis. To that end, I'd ask:

Does taking the extra time & effort to stuff cereal/wax/cotton balls/whatever, over top of powder, warrant the cost savings of just dumping more powder & seating a bullet?

Does saving a few shekels to blast cereal candles equate somehow to NOT shooting an actual bullet on target, and NOT reaping the reward of 'live fire' practice?

We all know shooting is a perishable skill, and building 'muscle memory' is accomplished via repetitive training. Brass forming intricacies aside for a moment, ain't no way imma trade actual shooting time, in favor of cookin' barrel breakfast. For me, cost savings vs. loading time and trigger practice do not equate. If it does for you, then it does...