Doppies inskiet / fireform cases

[Ds J]

Die vraag is eenvoudig: watter metodes bestaan daar om doppies in te skiet, en hoe doen n mens dit?

The question is quite easy: which methods exist to foreform cases, and how is it done?


(Vir die Afrikaanse deelnemers: daar bestaan sover ek weet nie 'n geykte term vir "fireform" nie. Ek maak dus nou die begrip "doppies inskiet". Soos wat 'n mens n teleskoop met 'n sekere lading inskiet, moet doppies ook soms ingeskiet word om by 'n spesifieke geweer te pas.)

[Krazong]

I used to do some fire forming with my 7x57 using a load of 10 grains MP200 and adding some tissue paper on top of that.  Filled with mielie meel, and then held into place with another wad of toilet paper.  Must be shot on a shooting range at it's nearly as loud as a real bullet.  Difficult to clean the barrel afterward and smells like burnt pap.

[Treeman]

I have done a lot of fire forming of bullets, and the most important part is not fireforming.
Annealing is far more important than the fireforming how to. Learn to destress your brass and do so before every step of your fireforming, even new brass is better annealed before fire forming.
That done, then shooting it.
I have a 210 liter oil drum plastic rubbish bin in my garage which use when absolutely full as a fireforming silencer. The full of garage and household rubbish drum has a hole barrel size  two thirds down the side and a thick old blanked foldeda few x over the top with a weighted lid over that. When I fire form I just place barrel in drum and do the deed, its no louder than dropping a phone book flat on a tiled floor or hitting the last hit on a nail when you hit the wood as well. I phone closest neighbour, tell her I will be doing some wood work, please let me know if I bother you. She claims not to have ever heard me. My wife sleeps about 4 rooms away when I work, no hassle.
I have used Mp - MS to achieve desired results, I also have a bottle of spilt propellant, droppings and leak out autoloader and Lee pro press. These droppings are everything hand gun, rifle and shotgun propellant.
I usually use 12 - 20 gr of mix for fireforming and I have topped charge with almost everything you can imagine, cotten, kapok, toilet paper. I have use Porridge, pronutro and birdseed, sawdust and shavings to a small load of birdshot. I have stuffed a case full of cotton wool and topped that of with soap forced into neck, I have poured wax in and used 2 mm of polifiller. I have used silicon sealer and even a small amount of Bostic contact dribbled on top of paper at mouth of the neck.
They all work, every way of making a bang works, sometimes just a tweak is needed to raise the resistance- pressure.
 ....................But please, anneal thos cases.

[Tripodmvr]

Ds J. Vuurvorm van doppe klink vir my heel skaflik. Dink ' bietjie oor vuurvorm. Jy skiet fabrieksammunisie en dit groep mooi en word vir jag gebruik. Jy het nou ook daardie doppe gevuurvorm en dit het ook verder hul doel gedien om biltong huis toe te bring. Tensy jy wildvreemde doppe soos ^Dasher of soortgelyk vuurvorm sal ek aanbeveel dat jy jag of skyfskiet en daan die doppe vorm. My gelaaide 243 ammunisie het baie goed in die 243AI kamer geskiet en die doppe het reg gevorm.

[Treeman]

Ds J. Vuurvorm van doppe klink vir my heel skaflik. Dink ' bietjie oor vuurvorm. Jy skiet fabrieksammunisie en dit groep mooi en word vir jag gebruik. Jy het nou ook daardie doppe gevuurvorm en dit het ook verder hul doel gedien om biltong huis toe te bring. Tensy jy wildvreemde doppe soos ^Dasher of soortgelyk vuurvorm sal ek aanbeveel dat jy jag of skyfskiet en daan die doppe vorm. My gelaaide 243 ammunisie het baie goed in die 243AI kamer geskiet en die doppe het reg gevorm.

**************************
Stem saam vir klein modifications, standard tot AI of Improved, skeit hom reg. Maar vir waare "fireform", - soos ek bo gese'

[Againstthegrains]

I agree with all of the above.

If you want to use fire formed doppies for accuracy, then just shoot a normal load. The stretch from SAAMI specs to your chamber is little.

If you want to fire form to a different caliber, e.g. 6BR to 6mm Dasher, then Treemans advice is very good, particularly the annealing!!! I know some cases even require 2 steps to get them into shape.

[Ds J]

Dankie vir al die raad!

Ek dink nie dit is wys om die huidige klomp gelaaide patrone verder te gebruik nie - daar was mos al vier foutiewe skote.

Ek wil almal uitslaan en dan vorm in die geweer.

- kan ek die slagdoppies veilig uitdruk, dan versag, en dan skiet, of

- gebruik ek die huidige slagdoppies om die doppe mee te skiet, dan versag en dan laai?

[oafpatroll]

I understand that the primers are 'set' on seating, i.e. they get slightly compressed so the compound is close enough to the firing pin and the anvil to reliably detonate. I'm sure you can get them out and reseat them again but is it worth the risk of a pants soiling if you get it wrong and the saving if you get it right?

[Ds J]

I understand that the primers are 'set' on seating, i.e. they get slightly compressed so the compound is close enough to the firing pin and the anvil to reliably detonate. I'm sure you can get them out and reseat them again but is it worth the risk of a pants soiling if you get it wrong and the saving if you get it right?

It is exactly my concern - a small amount of detonating compound going off on the inside of a depriming die might cause some trouble. It is not worth the risk.

[Tripodmvr]

Ek het al baie slagdoppe so uitgedruk en weer hergebruik sonder probleme. Dra 'n bril en druk dit stadig uit. As dit te veel druk vereis skiet liefs die dop in jou geweer.

[Treeman]

It is exactly my concern - a small amount of detonating compound going off on the inside of a depriming die might cause some trouble. It is not worth the risk.
[/quote]
**********************************
It does not cause issues, just a moerste skrik.Not to say it can not cause an injury, but it seems to just go bang and cause some blackness.
When pushing out live primers, make sure the rod does not seal the case neck (use universal or smaller caliber decapping pin)

[Newton]

Some time ago I touched on using compressed air .. the pressure needed for complete forming I discovered was 12,000 psi ( 828 Bar )
This idea caused a lot of concern as compressed air is dangerous - as dangerous as the gas from a fired cartridge ( in a rifle ) - 65,000 psi ( 12,000 vs 65,000 )
Anyway
The other method is .. Hydraulic forming using water - one can purchase special dies for this purpose

Please see here

Hydraulic Forming

Especially post no #20

I am sure my machinist buddy could make one of these
I am quite sure one could easily reach more than 12,000 psi
Although hydraulic oil under big pressure is as bad as compressed air

Another item to put on the list of experimental things to make  ...