Appreciate the advice! I'll put something together in the coming weeks. cheersNow, that dipping BOTH feet into the deep end!
I'm Presuming that you made your own draw dies - nicely done.
If you haven't already gotten to the shooting, and your jackets are <0.0005" wall thickness variation, you will likely be pleasantly rewarded with precision grouping. This is especially true when you have a grip on the material properties.
I do not want to hi-jack this GREAT thread, but am keenly interested in your project - please begin a new thread, keep us posted regarding your results!! RG
You'll need to be 700 degrees or more I believe. Practical Machinist hadThis draw back procedure is quite interesting to me. I am making 103gr BT’s on Sierra jackets. I am pre-forming the BT both on the jacket and the core. I am curious as to weather the cores can be stressed relieved at home in the oven prior to core seating. Temps and times would be helpful.
I believe they are discussing the Copper jacket and not the lead being stress relieved. Might be wrong however...Most bullet cores are pure lead or with a small amount of antimony. Lead melts at 622 degrees, so you would have a mess at 700. Lead is considered a "dead" metal, so stress relieving shouldn't be needed.
Yes, they are talking about the jacketsI believe they are discussing the Copper jacket and not the lead being stress relieved. Might be wrong however...
When I began drawing back the jackets to relieve some of the work-hardening, George, provided GREAT advice, which has worked flawlessly - DO NOT exceed 500* F. You do NOT want/need DEAD SOFT!!Yes, they are talking about the jackets
@geo.ulrich may see this and give more info about this
Thank you very much RG for that information.When I began drawing back the jackets to relieve some of the work-hardening, George, provided GREAT advice, which has worked flawlessly - DO NOT exceed 500* F. You do NOT want/need DEAD SOFT!!
I use a 'mickey-mouse' knife makers oven, with [argon] purge, but no vacuum , which would be better, but pretty pricey.
A kitchen oven, could work pretty well, you'd just need to regulate the heat - the oven my well do that well enough.My oven is programmable for all sorts of heating/cooling/purging facets (a LOT of overkill): the program I use for jacket draw-back, takes the temp up incrementally (need to match rate to purge to get a decent purge), to 475* F and holds it there for two [arbitrary] hours, then shuts off. I do not open the oven door until the temp drops back below 100*F, at which point, the temp is well below where rapid oxidation occurs.
This temp. will assure a [desirable] granular structure change , thus useful draw-back of work-hardening: a little residual resistance to 'working' is desirable . . .
Without purge, you'll have to remove the oxidation - but that's pretty easy. Even when the argon purge 'mostly works', a citric acid bath is still needed. So you don't have to back-track, here's the link again. < https://bibullets.com/bullet-making/ >
Note: "dead-soft" doesn't occur until the temp exceeds 650* F, but again, you don''t want to go there!
RG
I am curious as to weather the cores can be stressed relieved at home in the oven prior to core seating.
I do not know what Hines does, but believe that they do.@RGRobinett
the Hines 790 and 820 jackets I have been using for a while seem a little softer than J4
Are they drawn back by Hines?
I can attest to how great those 47's are.IThose jackets were 'saved' via obtaining a pinch-trim die and re-trimming, which COMPLETELY eliminated the 'folding', and made almost 10K GREAT 47 Gr. FB . . .
George, I agree - and believe that, when the mini folds and their larger siblings occur during point forming, the pinch-trimming (non uniform/square), regardless of manufacturer, is the usual suspect .Randy, After reading your last post I'm not sure you had a material issue but sounds more like an out of square pinch trim which will give nose folds ......