Case tempering

Rochelle

I am prepareing to fire form 348 winchester cases to the 12.7MM Swedish. I wish to soften the brass before fire forming. What is your method?

After they are formed and trimed how would you retemper the cases but not make them too hard?

Been a long time the last time I did this.

Dan

mrbruce

Annealing requires that the neck shoulder junction be brought up to enough heat so you get a faint Blue line just a little ways down the case, the distance depends on the case itself....
Normally a 1/4 inch below the shoulder is sufficient to get the job done....
Shine a case up really good and apply the heat, if the shine goes away, toss the case you messed it up by applying to much heat... My 6-6.5x47 Lapua cases stay under the flame for about 6 to 8 seconds..... Do it in a dark room and you can see the color show up......

nononsense

Rochelle,

These are basically straight wall cases used in the Rolling Block type rifles. I had to do this with the .50 Alaskan cases I played with several years ago.

"After they are formed and trimed how would you retemper the cases but not make them too hard?"

There shouldn't be any need because the cases will work harden with fireforming, reloading and crimping.

Best.

Rochelle

To return the temper, I have been told to place the cases in a baking pan with water deep enough to cover the case on it side. Stand the cases and heat the shoulder until it glows then tip it over.
Sound about right?

XXCross

Heating and quenching copper alloys (brass) makes them soft. It's the exact opposite of iron alloys. Brass hardens by working it. (forging or forming)

aap2

quote:Originally posted by Rochelle
To return the temper, I have been told to place the cases in a baking pan with water deep enough to cover the case on it side. Stand the cases and heat the shoulder until it glows then tip it over.
Sound about right?


rochelle: sounds wrong (you are describing annealing=softening). the water is to protect the casehead from getting hot (you need it to stay hard); heating the shoulder and tipping it in the water anneals (softens) the case, it won't make it harder. In my RB rifles, I fireform the cases then do all of the trimming and final adjustments to make a finished case. Depending on how much I have worked the brass, I then anneal the cases and load as usual. You may have great or lousy case life in a Rolling Block, depending less on annealing than headspace.

perry shooter

The strength of the brass case is needed in the case head area. The soft metal in the upper case walls and shoulder /neck area is a good thing the Barrel chamber supports the pressure not the case wall. you want the case to expand and seal the chamber to prevent gas flowing back and undue pressure on the case head