375 RUM Build

Discussion in 'Long Range Hunting & Shooting' started by Whitetail312, Jun 24, 2019.


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  1. Whitetail312

    Whitetail312 Well-Known Member

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    Please keep us posted on what he says!
     
  2. 375ultramag

    375ultramag Well-Known Member

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    20180714_140623.jpg I shoot a factory 700 BDL with bedded B&C stock and Muzzlebrakes and more 5 port brake. I was shooting 260 grain accubond handloads but I bought 3 boxes of barnes vor-tx 270gr. LRX ammo for the box so I could use the boxes for flying with airlines and decided to take a few shots with it and it shoots so good that I will just use up the rest before I reload anymore. 3 shot 100 yard group attached. 20180714_140614.jpg 20180627_205303.jpg
     
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  3. Whitetail312

    Whitetail312 Well-Known Member

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    If I’m reading right you can load our much longer with an internal mag versus using a detached magazine system too correct? That sure is a sweet shooting rifle.
     
  4. yorke-1

    yorke-1 Well-Known Member

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    It's as simple as a new barrel and a little work to the feed rails.

    You're a little limited by the OAL of a Rem 700 action, depending on the bullet you want to use. I use the 350gr SMK in my wildcat 375 BME which is a 375 RUM improved and load them to an OAL of 4.100" in a single shot. You need a pretty long freebore to make that work though. I'd also suggest getting a 1-10" twist barrel so that you'll be good to go for pretty much any bullet up to 350gr.
     
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  5. yorke-1

    yorke-1 Well-Known Member

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    Even with a Wyatt's extended mag box, you'll run out of space pretty quick with some of the longer bullets from Cutting Edge, Hammer Bullets or the 350gr SMK.
     
  6. adam32

    adam32 Well-Known Member

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    375 RUM and a .375 Cheytac are not even in the same league, let alone the same ballpark. So if you're thinking about scratching your Cheytac itch with a RUM you're gonna be disappointed.
     
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  7. 375ultramag

    375ultramag Well-Known Member

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    I agree with yorke-1 even with a Wyatt's extended mag box you are still going to be single feeding pretty much any bullet over 270-280 grains. I have a box of 281 grain hammer hunters and you could run them decent with a Wyatt's but mine is a stock mag box and I have to seat them pretty deep to run them.
     
  8. Whitetail312

    Whitetail312 Well-Known Member

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    I was originally looking to build a cheytac but even with reloading I don’t really think I could afford to feed it with the amount too shooting I wanted to do. So I was seeing if anyone had any luck with a smaller more affordable 375 boomer. I know they’re not anywhere close to the same, and one day I’ll still have one. But right now it’s much more feasible to use the spare action I have lying around.
     
  9. yorke-1

    yorke-1 Well-Known Member

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    You can actually get within 200fps (or less) of the CheyTac with a couple of the 375 wildcats. My 375 BME will run the 350gr SMK over 3000 fps from a 30" barrel. I won't say that this is a safe load in any gun, but I'm on load number 9 on the Norma 404 Jeffery brass that I've been using for the last few years. The various Lapua improved versions of the 375 can get into the same range too, but they won't work with your current action.
     
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  10. adam32

    adam32 Well-Known Member

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    Your BME has about 114gr capacity right? So a 378 WBY with 130+gr capacity should outrun a Cheytac then...?
     
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  11. Aoudad shooter1975

    Aoudad shooter1975 Well-Known Member

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    I've been shooting the 375 RUM for sometime. Nothing like you are looking at building. Mine are hunting rifles( sporting under 11lbs and shorter) my first one was built by Bill Wiseman in College station on a Remington 700 on a proprietary box magazine 24 in wiseman fluted barrel and is one of the most accurate rifles I own--the other is built on a magnum Gentry SS action 24 in Lothar walther barrel. I have shot Buffalo, eland, wildebeest,waterbuck, Impala, you name it...with a 375 RUM....it is ---- effective! I like it better than the old HH.
     

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  12. yorke-1

    yorke-1 Well-Known Member

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    My BME is at 121gr. to the case mouth. If you load a 378 WBY at the same 4.100" OAL it will run right with my BME, but the larger capacity puts it in a bit of a no man's land for powder burn rate. It's not big enough to really benefit from some of the slower powders like the CT can, but it's too big to work well with something like H1000. If Lapua sized actions had been more readily available when I built my BME, I would have just gone with the 375 Lapua improved. You'll get essentially the same performance (using comparable freebore) at a shorter OAL. I don't like the limited brass options for the 378 Weatherby but that would be the easiest way to get the same performance.
     
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  13. Doublezranch

    Doublezranch Well-Known Member

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    I have one. It’s my unicorn. It’s my favorite RUM I own. I have the whole set of RUMS plus RUM wildcats and I still think my 375 rum is the most fun to shoot. It’s crazy accurate, and a death ray with anything 270 to 300 grain bullet weight. Incredibly easy to reload for and just a very forgiving caliber.
    Yorke-1’s BME is a very cool cartridge. We have talked about it several times and I’m impressed with how he was able to wildcat the RUM case. His improvements really give the BME a huge edge over the standard 375 rum. I did make a 378 Weatherby Improved for my son Zayne. The 375 Zayne holds 142-144 grains and will run very close with the Cheytac. That wasn’t my goal when I built the rifle however I was pleasantly surprised when we saw the performance.
     
    Last edited: Jun 24, 2019
  14. yorke-1

    yorke-1 Well-Known Member

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    What did you end up with for velocities out of your 375 Zayne? You had a case capacity over 140gr right?