I've purchased a case annealing machine. I understand it is physically impossible to anneal my brass with it. I bought it because it is the best way to ensure that the exact same amount of heat is applied to the exact same part of the neck for the exact same amount of time, per batch of brass that I am heat treating. This will, as proven by many hundreds of people, using a variety of tools and methods, give me better neck tension consistency in that batch of brass.

I understand that the next batch of brass may not, and most probably will not, have the exact same neck tension as the previous batch, but I am reasonably certain that the next batch of brass will have near uniform neck tension within that batch.

Consider why neck tension cannot be relied upon to be exact across batches when using a gas flame :

• The distance of the gas nozzle to the case neck is not always exactly the same between batches.

• The length and size of the gas flame cannot be exactly reproduced each time the torch it lit.

• The amount of heat delivered to the case neck is a function of the distance to the nozzle, the size of the flame, and the remaining pressure in the gas bottle.

From those criteria alone, we can infer that the entire process is not precise, it is only approximate.

The uniformity of the result within each instance of process is higher than the uniformity between process instances.

The type of gas you use is not important. LPG, Butane or Propane produce the same heat ouput. For reference, LPG contains Propane and Butane, with other gasses.

Norma factory brass has legendary consistency. When used, it is not necessary to do anything to it other than prime and seat your bullets. After that first firing, all the case prep the world ever invented is geared to restoring that factory condition of the brass. Yet nobody does what they do - let the case neck stress relief be the last operation you perform before bullet seating, and you should get similar neck tension consistency to factory brass again. Remember, they are applying 14 seconds of heat ending at 600 degrees C, from the factory. That is the final heating operation before you seat your bullet in the case neck.