Recently the club I belong to purchased, for member use, a case neck annealing machine. Manufactured and invented here in New Zealand the device operates by induction and is programmable for hundreds of different cartridge cases. Why anneal your brass case necks? As brass is worked by sizing and firing (contracting and expanding) the crystalline structure changes and it work hardens. This results in longitudinal splits in the neck rendering cases useless or inconsistency in neck tension (how tight the neck holds the bullet) leading to accuracy issues.
Annealing case necks has always been a black art on a good day. One popular method written about countless times over the years by numerous gunzine writers was to stand cases in water deep enough to come half way up the cartridge case body and heat the neck up to ‘cherry red’. The water acted as a heat sink and prevented the case head and body from becoming soft; desirable for the neck but detrimental to cartridge case integrity. As cases were annealed the recommended action was to knock them over into the water to cool. It transpired that the water was unnecessary as heating the necks to ‘cherry red’ was far too hot for the purpose and when heated to the correct temperature of approximately 700F with a butane torch the annealing takes place fast enough that the lower section of a cartridge case is not affected. With enough practice the technique is workable but in my experience far from consistent.
Some smart individual then realised that lead melts at 621F and when casting is best run at about 700F; the magic number for cartridge brass annealing. The idea was that cases held by the rim would have their necks dipped into the molten lead until the rim was uncomfortable to hold. Great in theory but the one time I tried it my cases end up with lead coated necks.
Another idea was to apply heat sensitive crayon as used in welding applications to the neck of the brass. Each colour is calibrated so by applying the crayon for 700F to the neck of the case upon it melting the correct temperature for annealing has been reached and heating can be stopped. Another great theory but who needs crayon on their cartridge brass and the work that goes with it?
Annealing case necks has always been a black art on a good day. One popular method written about countless times over the years by numerous gunzine writers was to stand cases in water deep enough to come half way up the cartridge case body and heat the neck up to ‘cherry red’. The water acted as a heat sink and prevented the case head and body from becoming soft; desirable for the neck but detrimental to cartridge case integrity. As cases were annealed the recommended action was to knock them over into the water to cool. It transpired that the water was unnecessary as heating the necks to ‘cherry red’ was far too hot for the purpose and when heated to the correct temperature of approximately 700F with a butane torch the annealing takes place fast enough that the lower section of a cartridge case is not affected. With enough practice the technique is workable but in my experience far from consistent.
Some smart individual then realised that lead melts at 621F and when casting is best run at about 700F; the magic number for cartridge brass annealing. The idea was that cases held by the rim would have their necks dipped into the molten lead until the rim was uncomfortable to hold. Great in theory but the one time I tried it my cases end up with lead coated necks.
Another idea was to apply heat sensitive crayon as used in welding applications to the neck of the brass. Each colour is calibrated so by applying the crayon for 700F to the neck of the case upon it melting the correct temperature for annealing has been reached and heating can be stopped. Another great theory but who needs crayon on their cartridge brass and the work that goes with it?
Enter the good folk from ‘Annealing Made Perfect’ (AMP). Their invention has revolutionised cartridge case annealing from my experience. Here is how it works. First select a pilot to match the cartridge case to be annealed. The manufacturer supplies a full list of cartridges and matching pilots. EG: .308 Win pilot is #11. The pilot dictates the position of the neck in the heating area so shorter cases have shorter pilots and longer cases much taller pilots. Screw the pilot into the top of the machine and with the case held in a standard loading press shell holder drop the case into the machine. Next establish which program to use for calibre and case manufacturer by referring to the data base on the maker’s web site. Using .308 Win again as an example there is a list of 56 different makers/batches of brass provided with not only the program setting for standard neck thickness but also settings for necks .001, .002 and .003 thinner allowing for those who neck turn brass for better consistency. For brass of calibres and/or manufacturers that are not listed (of which there are not many) the device has its own analytical setting. A case must be sacrificed for this function but once done a program number is allocated and saved for future reference.
My 6.5X52mm Carcano has always been very hard on brass. Split necks have been the bane of myexistence and no amount of traditional annealing seemed to help as the casenecks are over worked during each sizing operation due to dies being ground tosqueeze down necks to hold .264 jacketed bullets; I shoot .268-.269 castprojectiles and expand to suit. As suchmy necks fired measure inside diameter of .271 then size down to .262 and backup to .268 – that’s a lot of work. Ihave been forced to anneal necks after each firing however using a butane torchproved inconsistent and far from ineffective as I can never be sure to annealthe entire neck with 100% uniformity all the way around. Now using the AMP prior to leaving the clubrange I run all my Carcano brass through the device and ensure soften necksprior to sizing. Today I sized all mybrass without the loss of one case.
One disadvantage of the AMP is the cost. USD1394.99 plus pilots at USD19.00 each (ex Grafs) so for an individual you would have to be very motivated and/or well heeled however when purchased for a club environment such as my club did this is great asset for the collective membership to share.
Jeff.
https://www.ampannealing.com/index/
Jeff.
https://www.ampannealing.com/index/