OzFclass

I know that sounds like it might be the case but the ONLY brass i have that loosened up fast was the 6.5-284, and that started from the word go. None of those were in the oven for long. .. I still have my 308 cases from 2009 ! and none of those have loosened up. I still use them. Still then i would recommend the oven at 100 degrees... why take the risk you are right there ...

With the 6.5-284, i have recommended loads like 45gr 2209, 47.5gr 2213 to someone in our club who is getting one. With 46.4 gr of 2209 & 140gr vld i was flattening primers and getting 3000 fps. The trajectory was what i wanted but the brass could not handle it, thats why i was thinking about the 6.5mm SAUM

Hello Tim,
I was under the impression that annealing only starts to occur once a specific temperature is reached and anything below this temperature will have no effects on the grain structure. I believe brass starts to anneal at around 250 degrees C so your brass shouldn't have gone through any annealing. Its interesting that the brass has had some discolouration though. Let us know how they go.
Josh

Keith’s advice should be heeded. When cases are manufactured they are placed in a big steel drum in an oven to soak for a specified time at a proven known temperature to change the grain structure. This happens about 10 times in the drawing process and the time it soaks and the temperature variation depends on the thickness of the brass at each stage of the drawing operation in annealing and tempering. He is right about the temper, which is a process after critical temperature is reached which is not as hot to change the hardness to an exact figure. Annealing is one thing and tempering is another. Going by the description of the colour, it’s a sure sign the brass got hotter than the oven indicated. Brass heats and holds its temperature quickly so even adjusting the temperature down cannot save you if the damage is done. The heat will draw to the thick part and hold, and that where your primer pocket is.

Any heat treatment unless the operator is skilled in reading colour charts needs the equipment verified. There is nothing like an oven thermometer which you can place in the kitchen oven and you can still buy. My grandmother used one on a wood stove. Better still, get an infra red temperature raygun for measuring temperature at a distance. The hairdryer is the way to go for Tim’s operation.

williada wrote:Keith’s advice should be heeded. When cases are manufactured they are placed in a big steel drum in an oven to soak for a specified time at a proven known temperature to change the grain structure. This happens about 10 times in the drawing process and the time it soaks and the temperature variation depends on the thickness of the brass at each stage of the drawing operation in annealing and tempering. He is right about the temper, which is a process after critical temperature is reached which is not as hot to change the hardness to an exact figure. Annealing is one thing and tempering is another. Going by the description of the colour, it’s a sure sign the brass got hotter than the oven indicated. Brass heats and holds its temperature quickly so even adjusting the temperature down cannot save you if the damage is done. The heat will draw to the thick part and hold, and that where your primer pocket is.

Any heat treatment unless the operator is skilled in reading colour charts needs the equipment verified. There is nothing like an oven thermometer which you can place in the kitchen oven and you can still buy. My grandmother used one on a wood stove. Better still, get an infra red temperature raygun for measuring temperature at a distance. The hairdryer is the way to go for Tim’s operation.

Thank you David In the course of my 40 year career as a full time gunsmith I have had to harden & temper many small parts with a gas torch using colours as a guide, so I have had some experience in these matters.
Keith H.

For the sake of common sense and the safety of myself and others, in the bin go my funny coloured overcooked 284 brass
Thanks Keith and others for your friendly advice

Hi All,
I purchased a stainless steel tumbler earlier this year and have been very happy with the results, but the tumbler uses wet media and I have always been cautious of getting my cases wet, like using an ultrasonic, you have to be so careful to dry your brass.

I used to use the oven, I would stand the unprimed cases upright on a tray case head down and only use the oven on 60 or 80 degrees for a couple of hours.

The website that I got my tumbler from started advertising a case drying device recently, but all it is, is a food dehydrator such as you would use to make jerky or dried fruit, it just so happens that I had one in the cupboard from years ago making a few batches of rabbit jerky and mucking about....on a side note, cutting up rabbit and removing sinew etc for enough to make jerky is a time consuming process!!

The food dehydrator has proven to be an excellent tool to dry cases, each tray can hold about 70 cases easily and dries deprimed cases in around an hour at about 60 degrees through the use of hot air being pushed through the various trays.

Worth knowing if you have one sitting around!

Cheers

Dave G

Canberra