300 RUM vs 300 WBY

Discussion in 'Long Range Hunting & Shooting' started by 4xforfun, Sep 14, 2010.

  1. 4xforfun

    4xforfun Well-Known Member

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    I have a 1000 yard comp BBL in 300 wby that just never amounted to much as a match BBL, so I am going to use it as a deer hunting bbl. BAT M 1.55 30" 1-10 twist. I decided to try some loads on the right hand side of the speed-o...if you get my drift.:D Anyway, I am up to 88 gr Retumbo behind 210 Berger VLD's. Been working up slowly. The last chrono data I have is at 84 Gr, and the AV was around 3025 for ten shots with pretty good ES. I had been gaining around 20 fps per grain, and it has been a very steady gain since I started at 78 gr. So, for sake of argument, I am at 3100, give or take, with ZERO PSI signs (other than the chrono telling me that they are "warm" lightbulb). Groups are hovering around the 1/2 MOA (5shot) mark......pretty much matches the best it has ever done while working up "comp" loads. Going to go up untill I get some sort of "sign". I think I am close. :rolleyes:

    My question......How much could I possibly gain if I rechamber this tube to a RUM throated to seat the bullets WAY long (like my WBY chambers all are...3.92 OAL with the 210 vld) and running similer PSI.

    I am not asking weather it would be worth it money wise. I just want some realistic #'s from guys who have rung the RUM out with the 210 -240 class bullets. I have never loaded for a RUM yet....been a WBY guy since day one.
    Kinda looking for an excuse to try one.:rolleyes:

    The reason is I have located a location for a bait pile at 1375 yards from my hunting shack in an otherwise unhuntable place. This is encroahcing on 338 territory....looking for max FPS w/o sacrificing accuracy. I am going to set up some steel as soon as I can get across the river.

    What say you ?
     
    Last edited: Sep 14, 2010
  2. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    I own several of both and have shot both extensively. On average there is 125 fps difference across the board and that runs very consistent gun to gun. In other words you can kill anything with one that you can with the other. 125 fps isn't much in a hunting situation. I really like both cartridges. I think you are fine with the wby but you can gain 125 fps if you want.
     

  3. Camshaft

    Camshaft Well-Known Member

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    I am pushing 210mks at 3190 with 94gr of Retumbo from a 26" pipe in my rum. You should be rubbin a hole in 3300fps if you seat em out long in that 30" bbl.
     
  4. Rocky Mountain

    Rocky Mountain Well-Known Member

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    208 Amax work real well in the 300s at long range.gun)
     
  5. 42769vette

    42769vette Well-Known Member

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    im starting to wonder if hornady quite makeing 208 amax bullets. they are never in stock anywhere i look
     
  6. J E Custom

    J E Custom Well-Known Member

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    You would gain velocity as stated, and you could clean up your chamber,throat and freebore
    and with a shoulder truing of .015 to .017 the logo would move to the bottom inside the stock
    for the new ID of the 300 RUM.

    Either way you have to take the barrel out of the action and you should true everything up.
    and not have to shorten the barrel but a few Thousandths and not effect the tenon threads.

    J E CUSTOM
     
  7. 4xforfun

    4xforfun Well-Known Member

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    I just re-inspected my brass with a magnifying glass....there is a very slight cratering of the primer at 88 grains which was not evident with the 87 and 86 gr loads. I can just feel it whith my fingernail if I concentrait. Now obviously the primers are flattend some, but they are all the same from my starting loads on up...identical.

    Like I said...I think I am getting close to the end of the line, speed wise...and with 1/2 moa 5 shot groups before the final "tweaking" I should be ok, accuracy wise. I will do some final testing when it gets colder, although the gun is in my heated "blind" (for lack of a better word) so extream cold temps probobly won't be an issue.