I generally try to stay out of these annealing threads because they often are asking questions about the machines which I don't use . I do use the method the OP is using with the temperatures he's trying so I'll chime in .
I've done a good amount of testing on this method and the only way to use 750* is inside the neck as shown above . The marks on the outside of the cases is 450* 1/4" to 1/3" below the shoulder and that is my desired method . As stated in another post cleaning the insides of the necks is a pain .
Yes I also use junk brass to get my timing down but it must be done every time you start a new batch or even if you stop and come back to it . This is because each time you start the flame on your torch the setting will be different resulting in a different flame temperature which changes the timing . I even go as far as if I'm annealing 500+ cases . Every 20 or 30 cases I apply tempilaq to keep me honest .
As for the 750* melting , it does not melt the same as the 450* . The 450 clearly melts and turn translucent while the 750* kinda just turns a different color , It's hard to explain what you see but over time you get the hang of it . Basically if you see any change in the 750* , that's what you're looking for .
How long should the case be in the flame ? I can say with almost 100% certainty that 10sec is way to long . With a standard propane torch the timing is generally about 4 to 6 sec . I have found that at about 10 sec the necks are glowing red or very close to it which is to hot and you made the case neck what I call dead soft . This results in low bullet hold and excessive sizing from head to datum with your standard die setting . Meaning with a dead soft neck and shoulder and your normal .002 bump setting on your die , you will be bumping .005 or more because the case is so easy to size with very little spring back .
As for can you heat up your case enough to get the head of the case to soft . Short answer is yes , long answer is no not even close . The cases above are the result of a test of me trying to do that same thing . I kept the propane torch on the neck and shoulder of the case until the 750* melted below the shoulder . The 750* did not melt until 10+ in the flame and the neck were glowing bright red . As you can see the 450* temp indicator at the web did not even melt meaning even when the necks were completely over annealed and basically trash the web still did not get hot enough . My conclusion was if the heat is applied properly in the correct place , you can't get the head to hot with out ruining the case as a whole .
I also tested different flame temperatures along with MAPP gas which burns much hotter then propane . Top flame is propane , bottom flame is MAPP gas . I have several photos of different durations in the flame for both along with the torches turned up and or down changing the heat of the flames . Long story short is that I found MAAP gas to be to hot for this method ( torch and socket ) because it heated up the brass to fast and my hand eye coordination was not fast enough to pull the case out of the flame fast enough before I felt the temperature of the case neck went higher then what was intended . I think MAPP could be used with a machine that could control the timing better then me watching for the temp indicator to melt then pull the case out of the flame .
Well It's late and I feel like I'm rambling . Hope that helps , I'm sure I left some stuff out . Feel free to ask me any questions I might not of answered or to clarify something .
MG
Has anyone experenced this? A misfire can be caused by improper annealing. When the shoulder becomes to soft, the firing pin strike can set back the shoulder. If the round fires, the brass expands, leaving no evidence of set back. I was shooting 223 Federal brass on its 6th loading. Having cracked necks, i decided that annealing might get a few more firings out of the brass. Even tho 40 years ago, annealing did not work on some 243win brass, making the necks to soft. The 223 misfire would not fire on the 2nd strike from the firing pin. At home, measurements show the shoulder was set back .014" when measureing to the datum line. L.E. Wilson's case gage shows the brass head below the lowest step. All loaded rounds had been gaged before firing. More testing was needed. Took 3 annealed brass with used primers and chambered them. After 2 strikes with the firing pin, shoulder set back was between .010" & .012" The used primer already had the firing pin dent in them, so the blow from the pin was not as great as new primers. The primer involved in the misfire was placed in a different non-annealed piece of brass. It did fire on the 2nd firing pin strike. A total of 4 hits on the primer, till it fired. I feel the primer may have been damaged from the first 2 misfires. Savage Axis bolt action 223 less than a year old. 722 rounds fired. Loaded with IMR4198-20.5gr-CCI400-Win. 55gr FMJBT-Federal brass-RCBS Dies made in 2010. I know here are Annealing Kits available & temp sticks that may help. But when you overheat the brass, there is no way to fix it.
