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    Case head expansion 300 Win Mag. What is normal?

    I'm having a difficult time finding good data on case head expansion for the 300 Win Mag. I'm using Nosler brass with Winchester magnum primers. I'm slowing working up my load in 0.5 grain increments. I have a micrometer (0.0001). After one firing, the case head expansion average is 0.0015 +/- 0.0002. Similar finding from 70.5 grains to 72 grains. Maximum load is 72 grains. My primers are a little flat but THEY ARE always flat even at my starting loads (65 grains) and they DON'T appear any different. No visible powder around the primers. No craters on the primers. No case head extractor marks. Bolt lift is unchanged. I'm concerned about the amount of case head expansion (on the belt) after one firing. Mostly because I can't find any good data on what is normal and when I should be worried. I would love a good velocity hunting load but not if it's hot. Plus I would like to get as many reloads out of the brass as possible.

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    Is the expansion happening transversly, (Diameter of the case head) and can you chamber them after being fired? It's been my experience the two times I've bought Nosler brass that the base of the cases were considerably softer than the other brands I use, Norma, Win, and Hornady. And, in turn, I only saw about half the case life in Nosler than I did vs. the others with the same loads/rifles. The cases will expand a little after firing, but as far as what's an acceptable amount is beyond my knowledge. Do you have other brands of cases to compare against with the same loads?

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    Quote Originally Posted by libidilatimmy View Post
    Is the expansion happening transversly, (Diameter of the case head) and can you chamber them after being fired? It's been my experience the two times I've bought Nosler brass that the base of the cases were considerably softer than the other brands I use, Norma, Win, and Hornady. And, in turn, I only saw about half the case life in Nosler than I did vs. the others with the same loads/rifles. The cases will expand a little after firing, but as far as what's an acceptable amount is beyond my knowledge. Do you have other brands of cases to compare against with the same loads?
    Thanks for your response. I can still chamber the brass after the first firing. Brass has not been resized yet. I don't have any other brands to compare. I'll keep researching. I might purchase some Nosler rounds and compare CHE. I'll avoid the latter if possible as Nosler rounds are costly.

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    I don't have anything that shoots a belted case myself, but a common problem you hear about with them reloading wise is excessive expansion just above the belt after a couple firings preventing the cases from chambering since the belt prevents the FL die from traveling far enough down the case to properly size this area. I think they still make a collet die that my brother uses for this problem found here http://www.larrywillis.com/index.html but it doesn't perform any sizing on the actual belt itself. Let us know what you find out.

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    If the bolt opens easily after firing, I don't think you have any problems. If it is hard to lift, then your loads are probably too hot. I never F/L size any of my cases after they have been fired....as long as you use them in the same rifle. I do shoot belted cases (.300 Wby & 257 Wby) in addition to a lot of non belted calibers.
    Colorado Cowboy
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    "My Father always considered a walk in the mountains as the equivalent of church going."
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