Re: 1st try at annealing. What do the experts think?
We're avid reloaders here and even have a lot of 1,000 Norma 7.5x55 bought some 20 years ago that are on their 20th+ reloads. If you're showing any red at all using your torch, you're over-annealing and will substantially shorten case life.
To save a lot of typing, these are from my old stomping rounds at the SRDC, and I agree with all of it. Within reason, nothing is cast in stone, and there are always different paths to achieve the same goal. If you really want to learn and save money on brass I doubt you'll need much more testimony after reading the following:
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Annealing is one of those things where "keep it simple" seems to apply. Unless you're doing an awful lot of handloading, any major investment in special annealing tools could probably be better allocated to simply buying new cases.
It's also futile to expend much effort on schemes for rotating cases. Brass conducts heat so effectively that there's hardly a need to rotate at all. Sounds crazy - until you try it. (Works best for me when I aim the flame at the shoulder where the greater surface area helps to spread the heat and avoid over-annealing the thin neck.)
http://theswissriflesdotcommessageboard.yuku.com/reply/11842#reply-11842
I used to think a water quench was necessary. Then I saw a picture of how ammo factories anneal cases - hey, no water! They just air cool after running the neck/shoulder between a row of burning gas jets. I stopped with the wet stuff and now just let the cases air cool. Once the heat source is removed, the physical process of annealing (which is actually a rearrangement of the alloy's crystalline structure) stops.
Water doesn't do any harm. it's simply unnecessary and it takes much longer for wet cases to dry than it does for dry cases to cool.
Back in the old days, when my only competition rifle was a No.4 mkII, I started to have a few neck splits after a few reloadings. I was (and still am) pretty cheap so I started to anneal to save my precious brass. I just held the necks in a propane torch flame and allowed them to air cool. Now with the advent of the internet I read about the water quenching and thought I must have been doing it wrong for all those years. So I started to quench them by having the brass in a pan of water and tipping them over into it. Seemed to work the same as the air cooled brass to me. After reading Para's post and also seeing how they do it at Federal, I'm thinking why not use the pan with water as a heat sink for the heads. Just don't tip them in after they've been heated and don't de-prime them until after the annealing, then no mess and drying time. That's what I'm going to try next time.
Jeff
The Perfesser of my undergraduate "Materials Processing" course (affectionately known as "Grunge Lab" at WPI) said "it doesn't matter how you cool 'em". Never-the-less, I have always used a brownie pan with 3/4" inch of water to protect the bases. The cases are already wet, so I just tip 'em over after the necks are up to temp. When done, I dump out the water, dump the cases on an old towel, roll 'em around, put them back in the same brownie pan and leave it in the oven overnight. The heat from the pilot light is enough to dry them out.
I have several lots of FA 29, 31 34 and 37 (U.S. 30-06) that have been reloaded over 40 times and still going strong, annealed about every ten firings. I also had a bunch of H 18 .30-06 cases (Remington, Hoboken NJ plant, 191 that were much used and reloaded and annealed, but after I got my first copy of Hatcher's notebook and read about the bad WW I brass and low number 03's, I tossed those.
Resp'y,
Bob S.
If the brass was clean before annealing, you will see subtle changes of color and reflectivity between those portions that were not annealed and those that are. Exactly what those colors are depends on the alloy (including impurities) the ambient light (you won't see anything blue under a dim incandescent bulb), and a bunch of other factors. US GI cal .30 or 7.62 ammo was required to show evidence of the final anneal and serves as a good example of what it looks like (sometimes).
Home annealing is more art than science. With experience, you learn to observe the subtle changes, particularly in surface texture, as you play the flame on the neck. Eventually you will see the progress of the crystalline changes as they move past the shoulder toward the head - and that tells you when to stop.
It's also totally unnecessary to rotate the cases. Brass is such a good heat conductor that heating one side works fine. Sometimes angling the flame half in the mouth and the other half on the neck works nicely, since it heats both sides - one from the inside and the other from without. When I'm feeling fussy, I just roll the case a half turn back and forth between thumb and finger. No need for elaborate spinning tricks.
http://www.gun-tests.com/performance/jun96cases.html
I began reloading when I was twelve years old (Lee Loader for .30-30 Win.). Since then I have reloaded many thousands of rounds in various calibers. I began reloading for the 7.5 Swiss immediately after purchasing my first two K-31s ('41 and '57) in the summer of 2004. I have found reloading for the 7.5 Swiss to be challenging. However, because of the great information available here from folks like Parashooter, Pierre and others, I also found it to be both interesting and fun. Here is a case study that you may find useful...or maybe not.
I use standard RCBS dies on a Redding single stage press. The components of my reloads have remained the same from the beginning, 168 gr. Speer Match HPBT over 41 to 43.5 grs. of IMR 4064 in a Norma case with a CCI 200 primer. I shoot the same reloads in five different K-31s ('41, '42, '51, '52, and '57).
I quickly learned about having to seat non-VLD bullets deeper than I had been use to with other calibers. I chose to discover which rifle had the shortest throat and set my seating die to that one rather than have a different setting (and reload) for each rifle. This has worked well for me.
I have found Norma brass to be great. It sizes easily and I have never experienced any problems with lack of neck tension. However, it is expensive. So, when I had fired the first batch about 5 or 6 times, I began reading as much as I could on this forum about annealing. I chose the Parashooter dry annealing method. I bought a butane torch at Home Depot and practiced on 100 .308 once fired cases I had gathered up (I don't reload .308 Win.). I began annealing the Norma brass and the necks and shoulders held up well. However, on the 13th firing, I had 6 out of 48 cases suffer 1/4 to 1/2 around head separation.
I began reading more postings on this forum about this subject. After reading a couple of postings (one very helpful one by Parashooter), I realized that I was slightly oversizing my cases a bit and probably shortening their life some. So, I took out a fresh batch of 50 Norma unprimed cases from my stash and decided to set my sizing die so that a fired case was resized barely enough to chamber without resistance in the rifle with the shortest chamber (the '57). When I did this, I realized that I had in fact been slightly oversizing my brass.
I just fired this batch for the 12th time and they look beautiful. I examined them last night while I was annealing them. They look great. No signs of weakness of the neck, shoulder or area just above the head. I trim the cases after every 2nd firing and anneal after every 4th firing. I will report on their condition under this thread when I anneal them after the 16th firing. I'm hoping to get 20 or more firings.
I'll repeat - Don't believe anyone who says to get the necks any kind of red hot.
The following is quoted from the NRA book Handloading -
"Most reloaders excessively heat the necks, causing formation of a large-grain brass structure, extreme softness, and lack of "spring" or ability to hold the bullets in the necks. This results from the usual advice, "Heat the case necks until red hot and then knock the cases over into water". While the necks so treated are indeed unlikely to crack, they may be so soft that they can be squeezed together between the fingers, which is a good way to judge their relative softness.
"Metallographers tell us that temperatures up to approximately 500 F. do very little to break down a hard, cold-worked brass structure. By the time the temperature reaches approximately 700 F., the cold-worked structure is gone entirely. A new, fine-grained structure exists with almost all internal stresses removed, making an ideal form of brass for case necks and shoulders. . .
"Further raising the temperature would only coarsen the grain structure, increasing the softness of the brass, lowering its resilience, and in no way improving its qualities. . .
"Actual "red hot" temperature varies depending on the observation conditions, particularly the lighting. But even when only barely visible in pitch darkness, brass has already been heated far beyond the grain refining stage and made unnecessarily soft."
As for enough heat running down the sides of the case to soften the head, this won't happen if the job is done right (no "red hot") and the heat source removed as soon as the telltale color line gets about 1/4" past the neck.
zfk55
