Annealing copper checks?

[RickinTN]

Hello all,
I have a couple of questions I know have been addressed here before, probably many times, but I cant seem to find it.
I'm having a couple of issues with copper checks and thinking that annealing them might help. My first issue is that after installing the checks and sizing and lubing my checks are larger in diameter than my sized and lubed bullets. I'm thinking this is probably due to the "spring back" of the copper material. The other issue is that on one of my 30cal molds the check to shank fit is very snug, and I find myself tapping the base of the bullet on my benchtop trying to get the check installed square to the bullet base. This bullet design has a tapered gas check shank.
I'm thinking that I could probably anneal the checks in my toaster oven which I use to heat treat bullets. If so, at what temperature and time should I use, and should I water quench afterwards or air cool them?
Your responses or pointing me in the right direction with previous threads is much appreciated.
Thanks,
Rick

[Calamity Jake]

Yep use your toaster oven to anneal, set the temp 450-500° spread the checks in an old cookie sheet heat for 45 minutes
then air cool they'll be soft and have little if any springback.
Washing the checks first to remove any manufactering lube helps to reduce carbon buildup on the heated checks.

[RickinTN]

Thanks for your help. I'll give it a try.

[Doc Highwall]

I don't think 450-500° is enough to anneal, I think you will need closer to 600° for about an hour.

[Char-Gar]

I have a small cast iron skillet that I use to anneal check. Dump the checks in and put on the stove top. Stir them around every once in a while, until they are all nice and black. Let them cool and that is that. It is worth the effort.

[.22-10-45]

I use a small hot plate..I find when they have turned to a nice brown color..not so hot to the point a black oxide forms and flakes off, they are as soft as needed. There will always be some springback..but I think this is an advantage as it promotes tight bore fit.

[Matt_G]

My oven goes up to 550.
Will an hour at that temp anneal copper?

[Matt_G]

Ok, I did some research and found that copper melts at 1357 Kelvin.
Several sources I read state that to anneal copper, you must bring it up to half the temp. (on the Kelvin scale)
678.5 Kelvin equals 762 Fahrenheit.
The self clean cycle on most ovens supposedly gets to 800 or more so I am going to try that.
Bought a black iron nipple and two caps, will put a piece of paper in there and I'll give it a whirl. :)