300 RUM problems

Discussion in 'Reloading' started by asfornea2, Nov 30, 2008.

  1. asfornea2

    asfornea2 New Member

    Nov 30, 2008
    I'm shooting a Sendero II chambered in 300rum. I have 3 questions a maybe potential problems. Overall length is 3.694'', 98gr retumbo, 180gr NBT

    1. When I bolt the rifle some rounds will be harder to bolt than others. All rounds are sized and loaded the same. Is this normal or whats going on?

    2. I'm noticing brass filing on my bolt face and at rear of chamber area. Whats causing this and is it normal?

    3. This gun has had maybe 50 rounds through it and I am noticing between the bolt lugs that thare is a flat spot developing on the bolt. If the rifle is bolted it would be on the left side of the bolt at the very end. What this from?

    Thanks for any help ya'll can give me
  2. Michael Eichele

    Michael Eichele Well-Known Member

    Jan 6, 2003
    1: It sounds like some of your loads have some run out. This could be why some are harder to chamber than others. Run out is when the necks of the cases are crooked. If you roll loads on a flat surface you can see the bullets woble. In other words they are not straight with the body. The side will bump the chamber and cause resistance. Runout is caused by expander balls found in full length dies.

    2: It is not uncommon to see brass slivers on the bolt and near the chamber. It is loose brass coming off during firings and unchamberings. Normal wear and tear.

    3: You may need to have a gunsmith look at the bolt????? Not sure what is going on there.

    Hope thats helps!

  3. lazylabs

    lazylabs Well-Known Member

    Oct 26, 2006
    Do you have any strange/shiny marks on your fired cases? I would check the case head for shiny spots and reach in and see if the chamber/feed area of your barrel is sharp. It could be your skinning your brass while chambering or running high enough pressures to cause a little brass flow in the ejector.
  4. AB8EAB8E

    AB8EAB8E New Member

    Jan 4, 2009
    Most likely run out, be sure to lube when sizing. I use Vaseline
    ( I trick from an old Comp. Shooter) Its good on your hands, and the brass too.
    I take a little and rub it in my hands and then take about 4-5 cases and roll them in my hands.

    Don't for get a WEE little bit on the Q-Tip for the inside.
    (I don't like doing this much because you will get different retention.)
    You will feel it when you press projectile.
    When your done Just wipe them off...

    Or ..I have used the Lyman aerosol spray...
    I don't use the RCBS Case slick. ... YUCK...

    Try neck sizing only. You have to make sure you only use the reloads in that rifle only.
    Also check your case neck retention I use about .002 to .003.
    If needed you might need to reduce the expander ball size.
    I remove it from the die then take it and put it into a drill and use a piece of sand paper and remove maternal
    from the expander ball. Then polish it with a piece of Scotch Bright...

    Oh the brass shavings from the Bolt...
    Is usually caused by the bolt extractor button..
    It scrapes the shell head the length of the bolt swing when you close the bolt.
    Remington type bolt ejectors springs ( Buttons ) are BAD for doing this...

    I hope this helps. I'm sure that there will be other ideas on this from other shooters... God Bless:)
    Last edited: Jan 4, 2009
  5. dmproske

    dmproske Well-Known Member

    Mar 2, 2008
    Between my dad and I we have 4 M700's. All great shooters. All of them get a little bit of brass shavings on the bolt face. Caused by the extractor. Never seemed to cause a problem.

    All of them also show the flat spot on the bolt between the lugs. Not sure whats up with that but does not seem to cause any trouble.

    Are you planning to take any game with that 180grn NBT? Thats a hot load behind a soft bullet. Plan to loose meat unless you take neck or head shots.

  6. Dano1

    Dano1 Well-Known Member

    Dec 20, 2008
    I'd also make sure that all brass is trimmed to minimum case length. Brass stretches and that could certainly be one of the problems especially if the brass has had multiple fireings. As far as run out on the cases, that certainly is a possibility, but I've noticed that firing the cases and full length resizing usually straightens out the run out to a managable degree. But I'd look at the expander ball on the die as well. you may need a new resizing asembely (sp) if it's crooked.

    Don't sweat the brass on the case heads, I'd really be only concerned if there is an ejectormark on the case head where the brass has flowed into the ejector hole. I have 4 Rem700s and all of them leave brass on the bolt face to some degree. Some are worse than others, but I think it's due to the caliber and larger case head (more friction on fired cases) it's a 7mm Rem Mag Sendero.

    If there is brass filings outside of the Chamber, and boltface, as stated earlier, check for sharp edges.

    The mark showing up on the bolt (if I'm understanding you correctly) is just behind and in between the lugs on the bolt. If this is the case, then it's being made be the tops of the resesses in the action, they are a little high. This happens occasionally, if it isn't causing problems, I'd not worry about it. I can be addressed by a good gunsmith if you want.

    Hope this is helpful,


    LONGSHOOTER Well-Known Member

    Oct 21, 2007
    On my early Sendero, I found that the cartridge cases (or bullets) were scraping on the top leading edge of the magazine, when feeding from the magazine). I had to dremel this area of the magazine insert for a custom fit. If this is your problem, go slowly with the dremel, while reassembling to receiver (no stock please), and checking progress, as you go.
    My earlier ADL has the same problem. Haven't corrected it yet. I would suggest checking all Remingtons for this interference.

    Do you have a riveted extractor? If you do, and it is the area I'm thinking of, then it is where the ejector rivet was grinded smooth after riveting. Not to worry.

    Last edited: Jan 5, 2009