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Hi,
I formed some 45-70 cases down to 33 win with a 33 win full length die. I found out that the case trim length is short. My case formed length measures 2.130 and it should be 2.165. Should I reduce the load to finish the form process?
Thanks.
November 7, 2015
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Good idea. Thicker case walls and shorter case likely will raise pressures. Hopefully they’ll grow a bit so you can trim them to the same length. I’m thinking a reduced load would be more pleasant to shoot so maybe a bulky powder will work for you. What powder are you using?
Mike
Mike I’m forming Starline brass and using IMR-3031. Before I formed the brass the case measured about 2.1. I was hoping that it would have gotten a
little closer to that 2.165 length. I have no experience forming cases this drastic. Would you think that they will stretch out closer to the 2.165 after fire form.
Guess I’ll know Friday. I’m thinking 34gr IMR-3031. Thanks.
Lester
November 7, 2015
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I don’t know, Lester. I always try to use correct headstamp brass but it seems any rifle case with a shoulder tends to grow a bit, some more than others.
Mike
You have not told us which bullet you are using. JSP or cast? I believe the standard loads produced about 2100 fps?
According to Donnelly’s cartridge conversion book the 33 Win case should be 2.105″. If you use his procedure to make it from 45-70 it says to run it through a form die or a 40-65 die then a 33 FL die. Then trim to length. Using a 200 grain bullet he says to use 32 grains of IMR 4198 for 1925 fps.
I would use the data that Mike Venturino’s book shows. 22 grains of Accurate XMP 5744 for 1635 fps with a cast bullet. He also shows the case to be 2.1″.
Barnes book shows to use 41 grains of 3031 for 2220 fps.
Williams book shows the case to be 2.11″. He uses 41 grains of 3031 for 2100 fps. With a cast bullet he uses 36 grains of 3031 for 1920 fps and 41 grains for 2099 fps.
You need to double check your case length measurements…..
When I make 38-56 cases out of 45-70 brass I first run them through a 40-65 die then the 38-56. This works but the brass is to thick around the bullet making the round hard to chamber. I suppose you could ream the necked portion. Buying head stamped brass is the best way if you only need a few boxes. T/R
November 7, 2015
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I agree with Chuck on Mike Venturino’s loads. Seems many cartridges I enjoy loading and shooting do quite well with 5744. I like 3031 but only if I feel the need for more velocity than 5744 will provide.
Mike
November 7, 2015
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Lester-
Did you anneal the Starline brass before resizing?
Mike
November 7, 2015
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I give up, Lester. Why do you want your case length to be 2.165”? I thought I knew but now that I’ve had a chance to research it a bit I agree with Chuck, best case length is 2.105. Is there something about the chamber that made you arrive at 2.165”?
Mike
Assuming the 45-70 brass is new and, therefore, still elastic, you may not have to anneal the cases prior to downsizing to 33, but the downsizing will create some ‘work hardening’, so if you want the re-formed cases to stretch, you should anneal them prior to stretching. I do this in the dark so I can see when the cases just start to glow red and then drop them into a bucket of water. If you over heat the cases (e.g., heat them in the light until they glow in well-lit conditions), you can ruin the case.
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