Best available powder to fire form brass

[marky_mark]

Figured out the chamber in my rifle is about 15 thou deeper than new adg or lapua brass
So I need to bump these shoulders out, without over pressuring them and causing the major expansion I’ve been seeing at the webbing
It’s for my 300 Norma so I’d rather not use up, hard to find powders, primers, bullets and barrel life
Wondering what powder and charge would be best, that is available, to do the cow method

[waldedw]

Back when the earth was flat, you know in the early 80's before the internet and google I had an old friend who was somewhat of a shooting enthusiast and I had to fire form a bunch of brass for my 7TCU and my 7BR, his instructions were short and sweet, drop down about 2 gr of powder from what your final load will be, load them up and pull the trigger, and Bob's your uncle it's done.

I am sure there should have been more to it but it worked, it was a painstaking process to make brass back then, no such thing as factory brass for those 2 rounds, I used a load that was about the middle of the spread loaded up a bullet and shot them.

I have never really worried about it with my rifles since, I figure the first time it's fired it's fire formed.

[Dick284]

Originally Posted by marky_mark

Figured out the chamber in my rifle is about 15 thou deeper than new adg or lapua brass
So I need to bump these shoulders out, without over pressuring them and causing the major expansion I’ve been seeing at the webbing
It’s for my 300 Norma so I’d rather not use up, hard to find powders, primers, bullets and barrel life
Wondering what powder and charge would be best, that is available, to do the cow method

Any shotgun type powder in the burn rate from Titewad to Green Dot will work, start at around 10 grains maybe add up to a couple grains if things aren’t blowing out sufficiently.

[spurly]

I think I used 12gr. Of Herco.

[marky_mark]

Cabelas has Tite group in stock

[brewster29]

Try forming a false shoulder by running the necks over an 8mm expander, then into your die to size the neck and set the new false shoulder just a couple thousandths tight for your chamber. You want your bolt to close hard on the lengthened case. Just load your normal load and shoot.

I use this method to make 280 REM brass from 30-06 brass, moving the shoulder forward 0.100”. Moving the shoulder 0.015” will be a breeze. No wasted components.

[marky_mark]

Originally Posted by brewster29

Try forming a false shoulder by running the necks over an 8mm expander, then into your die to size the neck and set the new false shoulder just a couple thousandths tight for your chamber. You want your bolt to close hard on the lengthened case. Just load your normal load and shoot.

I use this method to make 280 REM brass from 30-06 brass, moving the shoulder forward 0.100”. Moving the shoulder 0.015” will be a breeze. No wasted components.

What I basically have is a head spacing variance, and I’m just trying to bump the shoulders out as gently as possible lol

[rugerfan]

Red dot is my go to for forming with cow, but any fast burning pistol/shotgun flake powder should work.

[fps plus]

Originally Posted by brewster29

Try forming a false shoulder by running the necks over an 8mm expander, then into your die to size the neck and set the new false shoulder just a couple thousandths tight for your chamber. You want your bolt to close hard on the lengthened case. Just load your normal load and shoot.

I use this method to make 280 REM brass from 30-06 brass, moving the shoulder forward 0.100”. Moving the shoulder 0.015” will be a breeze. No wasted components.

This is the best way as it moves the brass without causing stretch that promotes case separation.
The other way is to seat bullet that jams into the rifling and fire.

[marky_mark]

Originally Posted by fps plus

This is the best way as it moves the brass without causing stretch that promotes case separation.
The other way is to seat bullet that jams into the rifling and fire.

I’ll have to see if I have a 8mm expander

[densa44]

Red Dot, when there was only rifle powder (3031) and shot gun powder, red dot, red dot was used for everything.

[Pathfinder76]

Originally Posted by marky_mark

What I basically have is a head spacing variance, and I’m just trying to bump the shoulders out as gently as possible lol

Pistol or shotgun powder likely won’t give you the desired result.

[BigJon]

I’ve never worked with a 300 Norma but have formed plenty of brass with a firm false shoulder and normal loads like brewster suggests. Use the rounds for checking drops/ringing steel/whatever. It sets headspace perfectly and brass will last a long time.

A .338 mandrel will work as well and probably be easier to find than an 8mm. If you were close by I’d let you borrow a .338 mandrel as I have no use for it for the foreseeable future.

[CBintheNorth]

I've got over 2 lbs of IMR7828 that I bought off a member here, and upon opening the tins found out it had started to develop 'the dust'.

Some say it's fine, some say it won't burn at a consistent speed anymore. Either way, I won't be loading hunting or target loads with it so if you can use it for this, it's all yours.
Saves me from dumping it on the lawn.

[Smokinyotes]

We use Red Dot for fire forming 30-338 Lapua improved.

[Dubious]

False shoulder and just use your regular powder. It’s the only way I’ve found to not get premature case head separation in just a few firings when fire forming brass for my ai.

[fps plus]

Originally Posted by Dubious

False shoulder and just use your regular powder. It’s the only way I’ve found to not get premature case head separation in just a few firings when fire forming brass for my ai.

If that is happening you ackley chamber was not cut properly .

[DLab]

Not sure this helps the OP, I fire form using 1-1.5 grains under the accuracy load with the bullets jammed for Ackley chambers.

A somewhat related question, thoughts on lightly lubing the case body to aid in forming, especially blowing the shoulder forward the amount the OP has mentioned?

[marky_mark]

Originally Posted by DLab

Not sure this helps the OP, I fire form using 1-1.5 grains under the accuracy load with the bullets jammed for Ackley chambers.

A somewhat related question, thoughts on lightly lubing the case body to aid in forming, especially blowing the shoulder forward the amount the OP has mentioned?

I’m leaning towards this
Or the false shoulder
I think the cream of wheat and no bullet won’t really address the issue I’m having. The case isn’t firmly held in the chamber and still going to have pressure going in multiple directions

[Dubious]

Originally Posted by fps plus

If that is happening you ackley chamber was not cut properly .

This I already know as well.

[Savage Bacon]

Originally Posted by densa44

Red Dot, when there was only rifle powder (3031) and shot gun powder, red dot, red dot was used for everything.

Frank's red dot?

Sent from my SM-G970W using Tapatalk

[brewster29]

Originally Posted by marky_mark

I’m leaning towards this
Or the false shoulder
I think the cream of wheat and no bullet won’t really address the issue I’m having. The case isn’t firmly held in the chamber and still going to have pressure going in multiple directions

I have blown out a couple hundred cases of 280 and made a lot of 340 Wby from 375 H& H using the false shoulder method. I find you can still get forward movement of the case sometimes if just seating long so the bullet jams into the lands.

Many (most?) of the wildcat cartridges have been formed this way.

The c-o-w method would also require a false shoulder- otherwise the ejector and firing pin will force the case in until the shoulder contacts the chamber and firing will not move the shoulder forward.

[marky_mark]

Originally Posted by brewster29

I have blown out a couple hundred cases of 280 and made a lot of 340 Wby from 375 H& H using the false shoulder method. I find you can still get forward movement of the case sometimes if just seating long so the bullet jams into the lands.

Many (most?) of the wildcat cartridges have been formed this way.

The c-o-w method would also require a false shoulder- otherwise the ejector and firing pin will force the case in until the shoulder contacts the chamber and firing will not move the shoulder forward.

Makes sense

[marky_mark]

Originally Posted by BigJon

I’ve never worked with a 300 Norma but have formed plenty of brass with a firm false shoulder and normal loads like brewster suggests. Use the rounds for checking drops/ringing steel/whatever. It sets headspace perfectly and brass will last a long time.

A .338 mandrel will work as well and probably be easier to find than an 8mm. If you were close by I’d let you borrow a .338 mandrel as I have no use for it for the foreseeable future.

Thanks! I have a 338 one myself. Think I’ll give it a whirl and see how it goes

[eric2381]

When I fireform Gibbs brass or Ackley brass, I make a false shoulder like Brewster mentioned, and I use Red dot powder, topped off with Cow and either white glue to hold it in, or a piece of toilet paper crammed into the neck to hold it together. I find that by firing this straight up in the air, it keeps my necks more square for some reason.

[Pathfinder76]

Fireforming brass with pistol powder works. But it will not consistently place the shoulders.

You guys creating false shoulders for forming AI brass need new chambers.

[eric2381]

It’s not necessary for Ackley chambers. I just do it to save bullets and wear and time with loads I’m not interested in using.

[Pathfinder76]

Originally Posted by eric2381

It’s not necessary for Ackley chambers. I just do it to save bullets and wear and time with loads I’m not interested in using.

A false shoulder?

[DLab]

Originally Posted by eric2381

When I fireform Gibbs brass or Ackley brass, I make a false shoulder like Brewster mentioned, and I use Red dot powder, topped off with Cow and either white glue to hold it in, or a piece of toilet paper crammed into the neck to hold it together. I find that by firing this straight up in the air, it keeps my necks more square for some reason.

Have a couple buddies that use this method also.

[duceman]

i haven't done the false shoulder, but use 10 gr of unique and top with cow to the top. then i use the wax from babybel cheeze to cap the mouth and fire with gun vertical. i make sure the case is full right to the top of the mouth before the wax so it compresses the 'load'.