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Green_Frog
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25-20 SS and 4759
Jul 30th, 2026 at 7:07pm
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I found an old article on loading for the 25-20 SS by Steve Garbe.  I was pleased to note that his smokeless loads used my old favorite 4759, but then noticed he was using Rocky Mtn Cartridge brass.  IIRC, that brass would be turned rather than drawn like the new Jamison stuff I just got.

This points up the question of internal case volume and ballistics. I believe the turned stuff will be somewhat smaller in volume.  This suggests to me that it will take a skosh more powder to produce equal pressure in the drawn Jamison brass.   

I know Steve used 7.0 gr start to 8.0 gr max (of 4759) for his loads in RMC brass, so if I understand internal ballistics correctly I should be gaining a slight margin of safety with lower pressure.  Am I on the correct line of reasoning?  I’ll still start with 7.0 gr unless I need to go lower for safety’s sake.  Any personal experiences that you guys can relate will be most highly appreciated.

TIA ~ 🐸

PS  ssdave suggested I anneal this new brass, assuming I would know how to do this, but that’s one process I’ve never even attempted.  Suggestions for a novice? 🤔
🐸
  
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Bent_Ramrod
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Re: 25-20 SS and 4759
Reply #1 - Jul 30th, 2026 at 9:10pm
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GF,

I use 7 gr of 4759 with the Ideal 257420 in a lot of my .25-20SS rifles, from 44-1/2s through 044-1/2s to Low Walls to a Stevens Tip-Up Ladies Model.

I still anneal by the simple way I read in a book somewhere back in the Pleistocene.  Go to a resale store and get two cake pans of sizes that one will fit inside another without sticking.  Put a dot of paint in the center of the smaller one.  Put an inch of water in the larger one, put the smaller one in the larger one and fill with water sufficient to cover the shell base.  Put a shell on the paint drop, spin the smaller pan and play a butane torch just below the shell mouth as the pan and shell rotate.

Some people advise doing this until the shell gets red-hot, but I do it only until the purplish-brownish discoloration forms evenly from the mouth to the shoulder (if the case has a shoulder).

I still remember our 8th Grade Shop teacher telling us, as we banged out bowls and ashtrays from brass, that we needed to anneal our creations in the furnace every now and then, but not to leave them in too long.  This would result in what he called a "dead anneal," which made the metal as ductile as possible, but maybe so ductile that the next session of hammer pounding would tear the metal or thin it more than we wanted.  Certainly my earliest experiments in annealing cases to this red-hot "dead anneal" state resulted in squashed shoulders and torn necks when the shell was full-length resized or something more violent in the way of case forming was done on it.

So my philosophy is anneal often (if necessary), but only moderately each time.  I would think some of the zinc would be burned out of the brass if the thin metal got too hot.
  
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Green_Frog
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Re: 25-20 SS and 4759
Reply #2 - yesterday at 7:58am
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Thanks, B_R, that’s exactly the info I needed.
Froggie
PS  I’ve heard that the brass should be tipped over into the water after it gets hot… do you do that or let the neck air cool?  Thanks!
Froggie
« Last Edit: yesterday at 8:32am by Green_Frog »  
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Jonathan
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Re: 25-20 SS and 4759
Reply #3 - yesterday at 9:41am
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I still anneal the way that I was taught by an old timer 60 years ago. Stand the cases up in a pan of water with half the case submerged, heat the neck/shoulder till red and just tip the case over. Easy and effective.
  
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Bent_Ramrod
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Re: 25-20 SS and 4759
Reply #4 - yesterday at 11:12pm
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Yes, GF; I knock the case over with the torch tip, fish it out and put another on on the spot.  Once my fingers are wet, I can spin the inner pan very smoothly and fairly rapidly.

There are very exotic annealing machines available, but I generally only need to anneal 100-200 cases at a time.  200 takes less than an hour.
  
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rkba2nd
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Re: 25-20 SS and 4759
Reply #5 - Today at 1:20am
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There are many ways to anneal cases. Some better than others, and this is a situation where better is best. I can assure you that cartridge case makers don't stand around a pond and heat the necks with a torch and then tip them over to cool. Also the reason there are much more precise methods/equipment to accomplish the desired result. The best are somewhat expensive, but precise results are worth the expense and safety aspect in my opinion.
  

rkba2nd
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