Bolt won't close on 300 RUM

Discussion in 'Reloading' started by yazoomark, Aug 12, 2011.

  1. yazoomark

    yazoomark Member

    Messages:
    11
    Joined:
    May 23, 2011
    Hey guys, my buddy is helping me develop a load for my 300 RUM. At the range yesterday he had 6 different loads of 210 Bergers. They were loaded with a COAL of 3.680. Quite simply, the bolt would not close with them seated so far out. Factory ammo and some other handloads that were seated deeper had no problem. My question to you is what is the longest COAL you are getting away with. FWIW my gun is a Rem Sendero SFII in 300 RUM and I'm using 210 Bergers and 180/200 Accubonds with Nosler brass. Thanks in advance.
    Mark
     
  2. Firecat

    Firecat Well-Known Member

    Messages:
    406
    Joined:
    Jan 10, 2010
    Every gun will be a little different in what the chamber tolerances are. I would consider buying a Hornady COAL guage for your rifle. If you are reloading anyway, then it will be to your benefit to know what the chamber is for your rifle. If you are wanting to know the "safe" COAL. Then SAAMI specs are written in every Reloaoding manual.
     

  3. Boss Hoss

    Boss Hoss Well-Known Member

    Messages:
    1,843
    Joined:
    Nov 10, 2005
    Edited
     
    Last edited: Nov 9, 2011
  4. Forrest Ebert

    Forrest Ebert Well-Known Member

    Messages:
    190
    Joined:
    Apr 22, 2008
    Did your buddy resize the brass correctly? If so did he measure and trim them to spec? 3.680" COL doesn't sound out the relm for the 300RUM as I'm testing some 200 grain hybrids for Berger in my 300 RUM with a col of 3.729" I suspect it's your brass have your buddy pull a bullet and measure the case I bet they are either too long or not resized correctly? If the bullet was seated too far out when you went to eject the loaded round the bullet would have pulled out of the case did this happen?
     
  5. baldhunter

    baldhunter Well-Known Member

    Messages:
    446
    Joined:
    Jun 18, 2008
    The way I do it is,take a case that has been fired in the rifle,but not resized.Next,mash the end of the neck on a hard surface just enough to give the bullet you will be using,some resistance when you insert the bullet in the neck by hand.You should have a tight fit,but still loose enough that you can push the bullet in by hand with a little resistance.Next,pull the bullet out far enough that you know it's quite a bit longer than it should be if it were a loaded cartridge.Next,open the bolt on your rifle and gently slide the case with the overextended bullet into the chamber and slowly close the bolt.Next,slowly open the bolt and carefully remove the cartridge.Now measure the COL and repeat the steps above several times to make sure you get the same measurement.Now you have the COL for your rifle with the bullet you've chosen to the lands of the rifle.I usually seat in from that COL,around 20-30 thousands and start my load test from there.
     
  6. retiredcpo

    retiredcpo Well-Known Member

    Messages:
    579
    Joined:
    Jul 19, 2009
    Is this new brass or fired brass?
    How did you come up with that OAL.
    I am guessing the shoulder of the brass needs to be bumped a slight bit more
    but cant be sure not enough info in you post
    I think to safely work up a load you must measure your camber to get a accurate distance to your lands
    retiredcpo
     
  7. forsyth793

    forsyth793 Well-Known Member

    Messages:
    52
    Joined:
    Jun 11, 2011
    Will your resized unloaded brass chamber and does your bolt close?
     
  8. yazoomark

    yazoomark Member

    Messages:
    11
    Joined:
    May 23, 2011
    Thanks for the replies! I think my buddy measured the magazine to come up with the 3.680 COL. Also this is brand new never fired brass. I don't reload so I don't know if he resized the brass or even if that is necessary on new brass. Also whenever I could get the bolt to close I never reopened it until after shooting so no it did not pull the bullet out. However when I would try to close the bolt it looked like the bullet was getting some wear marks just above the neck. Keep the info coming if you have any more suggestions. Thanks again
    Mark
     
  9. yazoomark

    yazoomark Member

    Messages:
    11
    Joined:
    May 23, 2011
    Update.....The brass was resized. Also the bolt closed no problem with just brass (no bullet). The rub marks on the bullets I think are the tell tale sign. Is anybody with a sendero able to load longer than 3.600?
     
  10. baldhunter

    baldhunter Well-Known Member

    Messages:
    446
    Joined:
    Jun 18, 2008
    Make you a dummy round without a primer.Blacken the bullet and follow my procedure,but if it won't chamber,don't force it.back out,pulling the bolt strait back. It should have visible marks where the bullets touch the lands.Use your seating die to push the bullet in,a little at a time until you get the round to chamber.Some like to seat the bullet touching the lands,I don't.It could cause you to have a high pressure spike.Every rifle is different,some have a short throat some have a long throat,that's why you need to check.One of my 308's has a very long throat,I can just seat my bullets to the max length of the magazine,but my 300WSM has a very short throat,so I have to be very careful because,with some bullets I have to seat less than the book COL.