338 WinMag to 338 RUM?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Sako7STW, Jan 14, 2013.

  1. Sako7STW

    Sako7STW Well-Known Member

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    I am wondering how hard would it be to convert say a Model 700 from a 338 Windbag to a 338 RUM or 338 Lapua. I am thinking making it a RUM would be pretty easy for a smith. The Lapua would require the bolt face being opened up and maybe an extractor?
     
  2. Frank in the Laurels

    Frank in the Laurels Well-Known Member

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    The bolt faces would be the only real problem as well as could the stock handle the extra recoil....My only question would be why?? I wonder if any animal would notice the extra few hundred feet per second difference in their lung and heart tissue. Why don't you just take the gunsmith's money and buy yourself a new 700 chamber in 338 um or one of the savage 338 lapua's.. I would think before I jumped at this change.. just my opinion
     

  3. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    I'm with Frank on this. Plus remember a m700 rum action has a bit wider action rails than the reg. ones, so machining costs go up a good bit. If You really want to step up a bit in vel. a 340 wby is your best option. It'll only do 100-200 fps more depending on pill weight, so even that is rather questionable.
    I contemplated a re-chambering on my #1 in 338 win for a few years, but at 2900 fps on a 225 already, I'd have to step up to a pretty big 338 to net much more. If I had my heart set on 250 grain+ bullets, I might think differently, but I have a 375h@h for that.
     
  4. woods

    woods Well-Known Member

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    I converted a Beretta Mato 338 win mag to a 338 RUM. However is has a long magazine at 3.685"

    Here are pics of the 2 cases

    [​IMG]

    [​IMG]

    So the case is .26" longer to start with. If your magazine is only 3.4" long like some of the win mag magazines are then you will not be able to rechamber to the 338 RUM and shoot any bullet with a pointed nose.

    In my magazine I still have to seat the bullets almost to the ogive in order to fit my magazine at 3.685"

    [​IMG]
    For instance here is a pic of a 225 gr TTSX and notice how it is seated all the way to the last cannelure
     
  5. angus-5024

    angus-5024 Well-Known Member

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    you can do it, or I should say a smith can do it. The feed rails need to be widened, but thats OK because you'll want a Wyatts outdoor extended box and follower (like $70) that needs some machining to fit (4.00" OAL possible).
    Bolt head opened up and barrel rechambered (may as well get it blueprinted and lapped while the tube is off).
    Since you are spending the money, get a new tube too.
    This would of course be for a .338 RUM, the Lapua is a little too Fat for the M700 action.

    I would do it if I had a 338 WIN simply because I find the round pretty useless for how I hunt. It would sit in my safe all the time, until I new I was bush wackin.
     
  6. Sako7STW

    Sako7STW Well-Known Member

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    I would buy a 338 RUM in a hearts beat but cant find one. It appears Rem quit chambering it as far as I can tell. I looked on there site and the guns it lists have all been discontinued. I would love to get a Lapua but it seams anything that has that name attached to it is twice as much. My main goal with this new gun is get a out to 600 yard monster that will hit like the hammer of Thor for Elk hunting that shoots rather flat. Here is the kicker, I want a Thumbhole stock. I have bought a Blackhawk Axiom UL stock and put it on my daughters M700 in .243. I love the way this stock feels. It is offered for M700 BDL Long and Short actions as well as Weatherby Vanguard. Now I have considered the .300 WBY in the Vanguard stainless but the main thing I don't like is the 24" bbl. So I have looked at the Mark V which I could get in any caliber and mount it in Stocky's thumbhole laminate. Overall, the Mark V option with a 338-378 would be the ultimate. It would however push beyond the budget I have right now.

    I am looking for something with more punch than my STW which is no small feat. I have noticed that when shooting BIG bull elk that my STW isnt doing quite as good as I would like. Pluss I cannot restock my gun to a thumbhole. Nor would I use my STW in Alaska or Canada on some hunts I plan to do in the future due to the threat of big bears. So I will keep my STW as a back up rifle and the one I would use on Antelope and deer.

    .338 Win mags are easy to find but I honestly hate them. I don't really know why but I do. I think I just am more of a velocity hound and they don't deliver the velocities I would be ok with (thus why I dont like the 24" bbl on the .300 WBY Vanguard.)
     
  7. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    I really don't get why 100-200 fps deficit to the bigger 338's suddenly makes a 338 win useless. The only kill I have on mine was at over 500 yards on a mule deer. The thing just flopped over dead. I usually use one of my 7's or my 300 win so the 338 doesn't get out much.

    Twas having a hard time looking at the rem site today; very slow and hung up more than a few times. I see they are playing the discontinue everything and throw out cheap crap for us to buy game again.
     
  8. woods

    woods Well-Known Member

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    Hey Lefty, because it is more like 350 fps. For example if I take the listed max velocities for the 338 win mag and 338 RUM from my Nosler #5 manual and average them for each on the 225 gr bullet

    338 win mag average 2787 fps
    338 RUM average 3144 fps

    that is a 357 fps advantage to the RUM and significant. I too grew tired of the low velocity of the 338 win mag and am now well pleased with the RUM. Now I am not a hyper velocity guy but do want to shoot a bullet with decent BC at, or very close to 3000 fps for some reason
     
  9. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    ok...
    for my #1 in 338 win I can drive my 225 hornady OR nos bullets to 2900 fps( these are verified by my oehler 35 p and the drop works out) with either h4831 or rl19 and I'm not even working the rifle. And most book data for 338 rum is 3100 fps for a 225. 200 fps it is. I can get a 250 to 2750 fps with rl19 also, and you'll have trouble getting over 2900 fps with the 338 rum; so 150 fps for that one. The #1 has a 26" bbl., but I'm talking to guys with 24" 338wins that are getting within 50 fps of me.
    The 338 win is a good cartridge many here are giving short thrift. Is is very efficient and does the job well. I wouldn't mind a bit more case capacity, but it has enough to function.

    As far as the OP wondering about a 338 rum; There are precious few available at present. I've only seen a couple for sale on the net today and haven't seen any locally in months. You are likely going to have to build a rifle.
     
    Last edited: Jan 15, 2013
  10. woods

    woods Well-Known Member

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    Lefty, for every example of someone who loads the 338 win mag to it's maximum velocity there are those with a 338 RUM who can and do load it to it's maximum which exceed the numbers you are giving here. IOW I have seen posts where someone has loaded the 338 RUM to 3250 fps with the 225 and 3100 fps with the 250. Not advocating it, just sayin

    You have to have some basis for comparison and averaging the maximum velocities is a better method than taking anecdotal evidence of someone's velocity on their specific rifle.
     
  11. Outlaw6.0

    Outlaw6.0 Well-Known Member

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    I agree with you, one cannot compare Field data to manual data- Apples & Oranges there. I can say that my 338RUM will (& does) push the 300SMK to a 5-shot average velocity of 2780 w/retumbo. I've seen a 5-shot average of 2812 with 7828.

    I'm not taking anything from the Winmag it's a fine round & coupled with the 225 CEB would probably be a dern fine critter hammer to 1kyds very easily. But a RUM it is not, never will be. There is no replacement for displacement & the RUM wins hands down.

    OP, if you want to go with the RUM, I say: why not? Do what you will, afterall it's yours :D

    t
     
  12. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    I never said the win wasn't slower, but you are giving it very short thrift. My brother in law has a 338 rum and my brother and I both have 300 rum's. I HAVE seen them in action.
    This is becoming a whose is bigger and I frankly am tired of wasting time with it.
     
  13. Sako7STW

    Sako7STW Well-Known Member

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    Lefty, your not wasting your time bro. I have been reading and taking in all accounts and advice. The reason I hate, and my whole family hates the .338 Win is because for several years we hunted elk with guys that had them and they wounded and lost more elk than anyone we know. It was more the shooter yes, without a doubt. We came to the conclusion that due to the slower speeds and farther distances they were trying to shoot (keep in mind, this was 20 years ago and they were NOT LRH'ers), they kept hitting them low. One guy switched to a .300 WBY and never lost another critter. So it is like that hypothetical truck you had that was a total POS and you would never buy another one even though the newer trucks they make are leaps and bounds better and would probably never give ya a problem. I vowed I would never own a .300 Windbag or a .338 Windbag back then and never will, unless it is a donor of course ;) . Stupid I know but hey we all have our quarks.

    Woods,

    Would you mind throwing a .340 Roy into your calculations there? Would be interested to see how it stacks up. I am really thinking on buying a .300 Roy in the Vanguard then retubeing it with a 28" stainless fluted in .340 Roy or .338 Tejas the next year when I have more funds again. My bro has a 300 WBY right now and has everything to load for it so the only thing I would be out is brass.
     
  14. woods

    woods Well-Known Member

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    Sure, later tonight when I get home to my manuals