fireforming brass

[gunnut14]

read a couple of articles about doing it and none seem to agree.
Wanted to get your opinions.
I am going to try and make 43 Mauser cases out of 45/90 cases.
reason
$3.50 each for bertram 43 Mauser cases and some are not even shootable with out a lot of work.
RP 45/90 cases are $1 09 each and the few I have are good brass.

Requires the rim to be turned down 15 thousanths and case shortened to 2.37 inches
Run it through a full length sizing die ans fireform the rest.
The article I most beleived said to use 13 grains of unique to fireform using 43 mauser boolit
The other article said to use COW along with the unique , did not speak of boolit.
Having never done it I am confused and need someone to lead me by the hand through the steps.

Any help appreciated


gunnut14

[Don McDowell]

45-90 cases are likely going to be to small in the case head, and they'll be short. But you'll want to measure your fired cases and make the comparisons.
44-90 sharps cases should be fairly close.

[Skipper]

Buffalo Arms has 'em for 2.35 ea if you buy 20


http://www.buffaloarms.com/Detail.aspx?PROD=157254&CAT=3839

[Lead pot]

Don.

Don is right.

Your working with a .516 head diameter if your chamber is anywhere near specs and the .45-90 brass has a head diameter of .500-.506.
When you fire those .45 cases you will most likely split the brass if not you will have a big bulge at the base.
Jamison now has brass that will work a lot better for your Mauser.
The new .44-90 BN brass has a head diameter that will work in your Mauser and you might want to check what the rim recess depth is for your chamber. If you have to much head space you will pull the necks off right at the shoulder.
They have two rim thickness, a .070 and the .079.
You would have to go with the .44-90BN brass the .44-77 will be .012 to short.

http://www.jamisoninternational.com/Brass-Cartridge-Cases-s/3.htm?searching=Y&sort=7&cat=3&show=10&page=4

[Lead pot]

For got.

If you need a thicker rim you can go to Huntington they have ,44 basic brass that has a rim thickness of .079-.082" depending if you get the Bell or HDS .44 basic brass.

[Chicken Thief]

I have a 71/84 and 45-90 brass underway too.

My original Mauser cartridge measures 0.586" at the rim and 0.518" in front of the rim, length is 2.355".
A 45-70 measures 0.594" t the rim and 0.498" in front of the rim.
The issue is the rim thicknes, Mauser 0.09" 45 brass only 0.065"

Doing research i came across a fellow that ran an 0.46" expander ball down the 45-90 shell as long as he could. To compensate for the smaller brass body.


Here's the route i'll follow:
1) Turn the rim down to 0.585" (check with bolthead!)
2) Anneal.
3) Run an 0.46" expander all the wat down the brass.
4) Size in increments until the bolt will just close slightly tight on a case. This way the cartridge will headspace on the shoulder instead of the rim. Alternatly size the snot out of the case and then fire it with a thin O-ring just in front of the rim (increasing "rim" thichness)
5) Trim to length

Pics of the Mauser case:
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010542.jpg
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010547.jpg
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010544.jpg
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010543.jpg

[Lead pot]

Well give it a try and see what happens and let us know.

[Chicken Thief]

When i change caliber/shape on a piece of brass i always go for broke and have fun at fireforming it with a full load or as close to full i can cram in.

Here is an example of converting 348 Winnie to 12.7x44R Swedish.
1) Anneal
2) Prime
3) Add a 38SPL case full of fast smokeless pistol powder
4) top of with corase cornflour
5) finish with a dap of wax/paraffin
6) form

It is a RB with a Vredes barrel from Swedens frontloader era, thats the reason for the funny rifling shape.
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/127x44fireforming1.jpg
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/127x44fireforming2.jpg

And as you can see it has a slight hourglas shape.
Loaded just waiting to be fireformed.
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/R0010550.jpg

[4060MAY]

use a piece of aluminum tape about a 1/4" wide in front of the rim to center the back of the case in the chamber, after fire forming take the tape off and you are good to go..the only problem I have with using the 45-100 brass is rim thickness, the step in the Mauser brass is for clearance of the ejector, the rim will be marked by the ejector, on a normal case this would be a headspace problem....
I made a shim and super glued it to the bolt face to take care of this problem, worked for about 200 shots and fell off, I will soft solder the next one on.
If you grind back the ejector about .020, and headspace on the shoulder, everything will be fine..after fire forming..I used Starline brass and annealed each time I shot it till the chamber was filled with the case

HTH

[4060MAY]

Picture of fired case, 2 times
small bulge about 1/2" in front of the rim
case seems to chamber and shoot
BTW Black powder only

[Chicken Thief]

4060MAY why the tape when the rim of the 45 brass is bigger than the Mauser and neds to be turned down? I would think that the rim will center the undersize cartridge just about perfect

[4060MAY]

tape around the case in front of the rim, to center the undersize case in the chamber.
now that I look at it, it may not be needed, if the necked portion is large enough to center the case in the chamber
the case should center with the rim and the neck the right diameter

I used metal furnace tape .004 thick which adds .008 dia to the case making the dia. .508, my cases at the largest point are .512.
I did turn the rims down .583-590 that's what they mic. at

The reasoning behind the tape was the LEE dies I used sized the brass down smaller than my chamber, probably could have bellmouthed the brass for a tight fit in the chamber to help center it.

one thing, the brass did not fully expand to the chamber till I annealed it to about 1/2" below the shoulder, careful not to go too close to the head

[Chicken Thief]

Gotcha mate, sound advise.

[Chicken Thief]

So the saga continues.

I got 45-90 brass and started by trimming the length (slightly long!), turning the rims down and then made a .46" FL expander to minimize case expansion at fireforming.
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010573.jpg
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010572.jpg

As you can see it does indeed bulge up the cases
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010581.jpg

On august the first a Lee dieset was sent from The US of A, and thursday this week there was still no sign of it so i made a pact with Murphy. You know the drill: If you lost something the easiest way to find it is to buy a substitute. So i ordered and payed for another dieset in Germany. What do you know? The USA set was in saturdays mail.

I annealed the cases and sized them, then trimmed to proper length.

A piece of 30 cal barrel was made into a wad punch, here with some milk carton wads.
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010574.jpg

I then filled two cases, one directly from the powder measurer and then one trickled down an old arrow. Dropped on the right, nearly 5mm lower in the case neck.
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010571.jpg

[Chicken Thief]

Then i desided how long my compression plug needed to be and added slightly to the diameter so the cases will take the PP boolits without tearing the paper:
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010575.jpg

Earlier this week before i got the proper dieset i thought that a 45LC sizer would be good to start the necksizing. Boy did that go like a fart in a diving helmet:roll:
It's the case on the left, apparently turtle necks and guns dont mix.
The case in the right is a case of compressing to much[smilie=1:
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010578.jpg

Here's the rest and 5 loaded rounds.

Load data:
78 grains of Swiss #4 (1½FG) compressed 4mm with a milk carton wad.
9mm greacecookie with another wad atop
Boolit handseated.

http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010579.jpg

BTV i think i got the headspacing thing nailed!
When my rifle arrives next weekend i'll try it for real, here goes:
A small O-ring is placed in front of the rim so the case is held against the boltface. Then when fireforming the round the shoulder will moowe forward to fill the chamber and no more headspace problems.
http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Mauser%2071-84/R0010583.jpg

[enfield]

the 71/84 does need the head turned down about .010 to .015 . but they work as is in a 71 action. just trim and anneal and full length size. works fine.

[elk hunter]

From the looks of the collapsed cases I'm guessing the annealing process made the cases too soft to stand being sized. I've had the same problem in the past. My current procedure is to heat the mouth of the case while holding the base in my bare fingers, when the case just starts to show a color change I drop them in water to cool them. I don't heat the neck until it turns red as I've too many failures when I did that.

I make 11 MM Mauser cases, to use for practice only, out of 300 Winchester Magnum cases. I de-prime them, turn most of the belt off leaving it at the proper base diameter to support the case in the chamber, bevel the base/rim of the case, put a small spring C shaped clip in the extraction groove, gently reprime, load with a small amount of pistol powder, fill with COW and put a wax plug on top and fireform, then trim. They aren't the perfect solution, but they allow me to shoot the rifle and save my expensive brass for hunting loads that have to function.

[Chicken Thief]

No Sir!
I collapsed the turtleneck case because it entered the 45 LC sizer slightly off center and i pushed on.