300 RUM with tight chamber help Needed

Discussion in 'Reloading' started by xtratoy, Mar 10, 2012.

  1. xtratoy

    xtratoy Well-Known Member

    May 21, 2008
    I have one of the first 300 RUM model 700 rifles that was available in this area when they introduced the round in 1999-2000. I got the gun fro the original purchaser and he never fired the rifle. That is the history of the rifle. My problem is that when I got it I purchased several hundred once fired cases. and a set set of Hornady Custom Grade Dies. After full length resizing the brass still would not chamber. I cursed the dies and slowly ground the shellholder so that the shell would go further into the die and be sized more. I finally found where I could get the brass resized to where it would chamber with minimal bolt pressure and reloaded some rounds to try it out. The fired brass chambers easier that the sized brass due to to fire forming in the chamber. Now my problem started once again. When I reside the brass trying to adjust the dies for minimal case resizing but resize the neck my brass was difficult to rechamber again. I am talking some serious pushing on the bolt. I finally broke down and bought a box of Remington Premier Ammo and guess what I can barely get the bolt closed on factory ammo. I was going to but a RCBS FL sizing die but after trying factory ammo I am not sure that this will cure the problem. What do you think about smoking-sooting an empty case and trying to find where the tight spot is and then trying to polish the chamber in that area ( spin a once fire case case with some super fine abrasive ) to fix the problem? Or do I need to find , borrow or rent a 300 RUM finish reamer and relieve the chamber a little. It doesn't seem like it will take much material removal to end up with a chamber that will close on a case like it should . Has anyone polished up a tight chamber like this with positive results?
  2. 7stw

    7stw Well-Known Member

    Jan 21, 2010
    You clearly have a headspace issue. I would take it to a smith and have it checked. He MAY be able to run a finish reamer through it and correct it, or he may elect to set it back, and rechamber. Firing that rifle like it is, is potentially dangerous due to pressure spikes, and not enough head room. At first, I thought you had a die problem, but when you said factory ammo wouldn't chamber, then I began thinking headspace. When in doubt, check it out!!!!!

    7 STW

  3. Gunpoor

    Gunpoor Well-Known Member

    Apr 28, 2007
    I had a Tikka T3 Lite chambered in 300WSM (my youngest son has it now) that had a chamber so tight I had to take the sizing die to a grinder and carefully grind the die body shorter to get enough shoulder set back to chamber new Winchester brass. It worked fine but some of the purists nearly fell off their pedistals when I mentioned this on a forum. I never tried any factory loaded ammo to see if it would chamber but I doubt it would. If you plan on reloading your own ammo for this rifle, if I were you, I would get your sizing die adjusted/altered so that it will work, but if you need to be able to shoot factory ammo you may need to have the chamber cut to looser tolerances. JMHO
  4. woods

    woods Well-Known Member

    Jun 4, 2006
    I would say smoke it and see where it is binding.

    IME Remington chambers are short-shouldered, large case body and long throated. Any of those causes it's own set of problems

    Redding will custom make you a body die if you send them a fired case. They will make it just a little smaller on the case body and will make sure the measurement from the bottom of the die to the shoulder is short enough for contact
  5. vanhornsky

    vanhornsky Well-Known Member

    Apr 6, 2010
    I would take it to a smith and let them look at your face is much more important than the fee to get it checked. The other thing that you could do is buy a go gage for the chamber and see if the bolt closes. If it doesnt the headspace is definatly not right. Have a good day.