300 WSM sizing

I'm having trouble chambering rounds after reloading. It seems as though the full length sizer is not sizing all the way down. Thw cartridge is going in the chamber but the bolt is difficult to close. Any suggestions????????


  • BGHillbillyBGHillbilly Member Posts: 1,927 ✭✭✭✭✭
    edited November -1
    Need more info but generally there are a couple of possibilities, if you chanber a round and eject it, where are the wear points? If you see rifling marks on the bullet then it may be a problem with overall length which should be checked anyway. You may see marks on the brass near the shoulder area it's an indication the case may becoming deformed during bullet seating. I would try chambering a resized case before priming and bullet seating also.
    I guess we can assume factory rounds chamber ok?
    What caliber and bullet style?
    What type gun?
  • blackmesariflecoblackmesarifleco Member Posts: 91 ✭✭
    edited November -1
    I have ran into this in two ways:
    1. If the die was not set right or the die made incorretly that the shoulder was not set back enough thus creating a crush effect with the bolt.
    2. I had two sets of dies that were made wrong and the diameter of the case was not being shrunk enough so that it was tight closing the bolt. I could use a different set of dies and be fine. Resized some brass with different sets of dies and measured the cases.
  • skyfishskyfish Member Posts: 1,068 ✭✭✭✭
    edited November -1
    I would rule out bad adjustment 1st. Is the shellholder touching the base of the dies at the top of its stroke, check that. If it is, check that it contacts when sizing a case. My very old press and shelholder would contact with no case but when sizing there would be about a .015 gap, not sure where the play came from either , but I had to put a little pre-load on it. Could just be your lock ring moved, does happen.

    That's the easiest, start with that then go the other stuff.

    Just a side note, I find the lock rings that pull the whole ring together hold much better than the ones with a brass plug that threads into the die threads.
  • Tailgunner1954Tailgunner1954 Member Posts: 7,815
    edited November -1
    Take things one step at a time, when diagnosing a problem.
    Use a magic marker to color a round (soot from a candle flame works too) that's not closing, try to chamber it and than remove it and see if you can spot rub marks from where it's contacting the chamber.
    Without seating a bullet:
    The first thing I'd do is remove the decapping/neck expanding stem, and try sixing/chambering one that way.
    If than does the trick, than try putting a slight amount of lube inside the neck and/or polishing the expander plug.
    Second, I'd try what Skyfish suggested (making sure that the die is contacting the shellholder when sizing), both with the expander in and with it removed.
    Third, assuming that it is chambering sized cses OK, raise your seating die 1/2 to 1 full turn and seat a bullet with the die body elevated (you may have to lower the seating stem at this point, to get the correct OAL) and try chambering this "dummy round" (if the crimp ring in the seating die is contacting the case mouth, you might be bulging the shoulders).
  • joesjoes Member Posts: 484 ✭✭✭
    edited November -1
    I have a tikka in 300 wsm and that chamber is VERY TIGHt ( even with factory loads) but shoots 1/2" groups all days with both reloads and factory. That die has to be set just right or it too will not allow the bollt to close. I have heard in the past that the nickel brass is slightly thicker than the regular brass and may be an issue but I would tend to believe the die is screwed down too far and is causing the top of the case to crush.
  • perry shooterperry shooter Member Posts: 17,390
    edited November -1
    Is the st of dies the same brand as the shell holder [?]If not the die may be stoned shorter to allow it to go down further before hitting the shell holder. The most common cause of your trouble.
  • sandwarriorsandwarrior Member Posts: 5,599
    edited November -1
    Once, you've gotten through all the suggestions about how to bump the shoulder back, which I strongly recommend, you may need to anneal the brass. Once the brass has been fired a few times it likes to spring back. Moreso with the thicker WSM brass.
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