300 RUM--OAL Trouble

Discussion in 'Reloading' started by knc1105, Jul 2, 2010.

  1. knc1105

    knc1105 Well-Known Member

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    I finished a new Rem. 700 Police 26" factory bull barrel we put a Miculek muzzle break on etc.., etc.... I have checked OAL to the lands on 210 SMTKS, Berger 210 VLD, 210 Berger Long Range match, 180 gr Accubond, 200 Accubonds and they run from 3.800-3.815, but the inside the magwell is 3.725 max the book OAL is 3.600. If I load to be able to use the magwell, I'll have a .085- .100 jump to the lands. I new Weatherby's were a long throat but I had not seen a Remington like this. Is there a chance it will shoot? Sounds like the Bergers are out. Any help / experience would be appreciated. Looks like I can't get a decent oal until I set the barrel back.
     
  2. Coyboy

    Coyboy Well-Known Member

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    get a wyats extended window box for it and instal, it will increase mag box length by about .100"
     

  3. 300R

    300R Well-Known Member

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    +1 with cowboy,my sendero was the same i went with the wyatts or seekins makes a dbm if you want to go that way,they both require little mods.
     
  4. knc1105

    knc1105 Well-Known Member

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    Were do I get that??? The Police version has a H & S precision stock, does that change the options? THANKS
     
  5. knc1105

    knc1105 Well-Known Member

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    OK, I found the extended boxes, how hard are they to install??? I'll get my gunsmith to do it, but the bigger jobs get in line and the smaller jobs he'll work in sooner.
     
  6. woods

    woods Well-Known Member

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    Hey knc

    The RUM factory chambers all have long throats, at least all of the ones I have loaded for and heard of. The one I am working on now (Sendero) has a mag length of 3.700" and the 200 gr Accubond hits the lands with an OAL of 3.785". So in order to stay away from any problems with the tip of bullets hitting the mag during recoil or being broken off while being loaded into the magazine, I seat them at 3.625". IMO you can accomplish the same thing as seating depth variation with slight changes in the powder charge, it is all a matter of barrel timing
    [​IMG]


    IOW don't think that you can not find an accurate load just because you can't seat close to the lands.

    The Wyatt's box is interesting though and being a DIY guy, I am interested to see if anyone has done the installation themselves.
     
  7. 300R

    300R Well-Known Member

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    Not a 2 minute job if you don't have a mill,but also possible with a steady hand and a dremel with a good carbide cutter.
    INSTALLATION INSTRUCTIONS
     
  8. knc1105

    knc1105 Well-Known Member

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    OK, I firelapped the barrel and tried 3-loads yesterday, 40 rounds total. It shot great with a .085 jump to the lands on one load and a .095 jump on the other two, I don't know how. All the loads I tried were from a thread here on 300 RUM loads. The 180 AB 97 grs Retumbo shot a cloverleaf with one flyer that was probubly me. The 200 AB with 94 grs of Retumbo you could cover 5 with a dime it was great. The 210 Berger VLD Hunting at 92 grs of Retumbo 4 of 5 could cover with a dime and the 5th put it at a nickel group. I am still going to have the extended box put on because I think it will make it shoot even better and I think the throat will last longer with a .005-.010 jump. I REALLY appreciate ya'll and all your help. I did not even know about the extended boxes, so you learn something new everyday. Thanks, Ken
     
  9. alf

    alf Well-Known Member

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    All you have to do is work loads up to either Wyatt's length or closer to the lands before you take the plunge. May be a moot point.
     
  10. freebird63

    freebird63 Well-Known Member

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    I have installed the wyatt window box myself, was not as bad as I was thinking it was going to be. Somewhere I read where someone was commenting on how the hornady OAL gauge was not very accurate so last night I loaded up some dummy rounds and checked for myself. With the hornady gauge it showed my rounds with a 210gr berger to be and thats measuring with a comparator, 3.155 inches. Well when I loaded up the dummy rounds last night boy was I in for a big shock. With the dummy rounds to the lands is actually 3.200 inches. Base to tip being 3.900 inches. So that window box I installed will not allow for the rounds to be put in the magazine. So now I have to more or less start my load development all over again. I hate it when that happens. Actually it won't be that bad as I already know that .090 off the lands shoots pretty decent. So now I just have to go back and try at the lands(3.200), .010(3.190), .020(3.180), .030(3.170), .040(3.160). So that should be fun. I finally might get the groups I have been trying for.
     
  11. boomtube

    boomtube Well-Known Member

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    "... inside the magwell is 3.725 max the book OAL is 3.600. If I load to be able to use the magwell, I'll have a .085- .100 jump to the lands. "

    First, loading long to get close to the lands is a Bench Rester techinque, often poor practice for us. Few sporting rifles (that is, anything not BR rifles) do their best seated close. Neither our rifles or ammo is more than casually like BR gear and much of what they do is not only unhelpful for us but can actually be harmful to our best accuracy.

    Second, any book OAL is only a suggestion, a starting place, not a requirement. It's not even a recommendation, it's listed for those who don't yet know what to do. I've never paid any attention to book OAL in more than four decades of reloading. In fact, many old and some new data sources don't even mention OAL.

    Try some load development the rifle the way is, you will likely be satisfied, within the finite limits of the barrel anyway.
     
  12. bigbuck

    bigbuck Well-Known Member

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    I installed my wyatts Ext box mag . I used a high speed drill with a dremel /grinding tool bit I actually wor out two sanding stone bitts while grinding but it was accomplished :) . You could load some up to feed like a single shot just to see if your rifle would benefit then if satisfied take the plunge and install your own ?

    I used to have pics of a LRH member that had installed his own and it helped me alote. If you need them I could email them to you if I can find them again , just let me know any way i can help .
     
  13. Hired Gun

    Hired Gun Well-Known Member

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    The Bergers will work fine. I seat them to 3.7"to feed from the Sendero. I'm getting 3200fps with Retumbo and dime size 5 shot groups.
     
  14. freebird63

    freebird63 Well-Known Member

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    How much Retumbo you using to get that kinda velocity?? are they 210gr bergers?
    I am on the average getting 3020-3040fps with 210gr bergers