7.5 Swiss from 284

dennis53

August 07, 2005 16:24

I am having trouble getting ammo to chamber properly in my K-31 Schmidt-Rubin. They are reloads from 284 brass run through RCBS dies. I full-length resize, but the shells seem to get hung up at the very base of the cartridge near the rim. Any solutions?

Thanks,
Dennis

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  nononsense

  August 07, 2005 19:08

  Dennis,
  
  The base or head size of the U.S. .284 Win. brass should measure 0.500" in diameter while the 7.5 Swiss will probably be about 0.493" in diameter. Your sizing die may not be turned down all the way in order to resize the base or the die just may not be ground small enough to do that. It has been mentioned before that there can be some variances in the Swiss chambers, enough so that your brass may not fit without having a specific sizing die made, something along the lines of what's called a 'small base die'.
  
  Best.
  
  You also need to check the various lengths of the brass that you're using, neck, shoulder, body, et al.

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  Pearyw

  August 08, 2005 07:47

  You can buy 7.5 Swiss brass from Graf's for about $28 a hundred. I have used their brass in a set of Lee dies without problems in my K31 and my 1911 Schmit-Ruben.

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  nononsense

  August 19, 2005 07:14

  As long as we are talking about chamber variations, here is a photograph of 2 CerroSafe castings from different rifles:
  
  

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  dennis53

  August 22, 2005 08:09

  Thanks for the good advice and very interesting photos.
  
  So what brand of (factory) die do you guys use
  to form the 7.5 from 284?
  
  
  Thanks,
  Dennis

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  jonk

  August 23, 2005 17:24

  I use Lee dies and have never had a problem with the .284 brass, but every set of dies and guns varies slightly....
  
  "...hit your enemy in the belly, and kick him when he is down, and boil his prisoners in oil- if you take any- and torture his women and children. Then people will keep clear of you..." -Admiral of the Fleet Lord Fisher, speaking at the Hague Peace Conf

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  mazo kid

  August 28, 2005 11:08

  Try chucking the brass in a drill press and filing a couple of thousandths off the head, where it is binding. Emery
  
  "Well done is better than well said"
  Ben Franklin
  NRA Life
  NMLRA Life

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  sandwarrior

  September 10, 2005 19:45

  Dennis53,
  
  I've waited a while to respond to this as I am working up loads for the 7.5 Swiss in my K-31's. If I can give you a good temporary resource for 7.5 Graf brass it is www.gunstop.com this will save you from fireforming or forceforming the .284 Win brass. It also has the right base(head) for the K-31 rifle. I have really started to like this round. keep in touch on your progress.
  
  We have the second amendment so that all the rest are secure....UNK>

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  dcloco

  October 07, 2005 14:54

  I resisized my 284 Win brass Wednesday night, shot at the range last night...no problems at all.
  
  Cases are now completely fireformed (shoulders at a slightly different angle than the 7.5x55 swiss round.
  
  NO extraction or feed problems either.

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