.375 RUM with 350 MTH performance??

[codyadams]

So my cousin just finished building a .270 Sherman, which has essentially replaced his 13 lb rem 700 long range 7mm rem mag. So the 7mm rem mag will likely be rebuilt, and he wants to go big.

So big, long range, and still work on a 700 action, pretty much comes down to a RUM case.

So my question is, does anyone have a long throated 375 RUM to run the 350 MTH bullets or similar high bc bullet suitable for hunting? I'm wondering what kind of velocity you would get if they were properly throated. Of course, this would be a single shot set up. It would be used for cross canyon elk smacking as well as the occasional ELR fun. Wanting to keep it idaho legal, so just under 16 lbs.

Any other suggestions for cartridges are welcome, we are just in the spit balling stage of this build now. It likely won't be for a couple years.

Thanks all!!!

 

[yorke-1]

So my cousin just finished building a .270 Sherman, which has essentially replaced his 13 lb rem 700 long range 7mm rem mag. So the 7mm rem mag will likely be rebuilt, and he wants to go big.

So big, long range, and still work on a 700 action, pretty much comes down to a RUM case.

So my question is, does anyone have a long throated 375 RUM to run the 350 MTH bullets or similar high bc bullet suitable for hunting? I'm wondering what kind of velocity you would get if they were properly throated. Of course, this would be a single shot set up. It would be used for cross canyon elk smacking as well as the occasional ELR fun. Wanting to keep it idaho legal, so just under 16 lbs.

Any other suggestions for cartridges are welcome, we are just in the spit balling stage of this build now. It likely won't be for a couple years.

Thanks all!!!

Properly throated and used as a single shot you should be around 2900 with a standard 375 RUM and a 350gr bullet. I shoot the 350gr SMK at 2950fps in a 375 RUM improved called the 375 BME. It will run them over 3050fps but the accuracy is significantly better at around 2950. This is using an OAL of roughly 4.100".

I played with the 350 MTH very briefly a few years ago and had very poor results. The best I could come up wit was that the bullets weren't stabilizing properly because they were slipping in the rifling. I would get occasional bullets that would just go completely off track and seemingly fall out of the sky. I went back to the 350 SMK and never had another issue. That said, I just recently tried the 155gr MTH in a 7mm SAUM and they shot great out to 1380 yards so I may need to rethink my opinion of the CE bullets.

I've only used my 375 BME for targets so the 350 SMK has been great for me. If you did want to hunt with it I would expect it to perform just like the 300gr SMK in a 338 Edge or Lapua.

 

[nbowlin]

we shot the 350smk into bleach bottles and got a nosed over bullet every time. Never opened. Didn't have the speed you will....2700, but still. Steve has the 329 hammer hunter and if I ever get the rifle back from the gunsmith inletting a stock for it bc can be confirmed.
The hammers opened for what it's worth.

 

[Wolf76]

Just completed a 338 edge build on a r700 la. It has a hells canyon CF barrel, wyatt's mag extender, ejection port opened, and a manners thumbhole stock. Gun shoots a 300 gr Berger sub .5moa @ 2820 fps. I'm very certain it will smack elk near and far. Could shoot a 250 Berger @3100+.
The best part is the gun touches the scales at an even 10# and is easy to shoot. Not sure what the 375 rum would do better.

 

[Rum Man]

Following we have talked about the 375 Rum also !!

We talked to a Engineer from Proof the other night about the barrel . We would need to order in a large quantity to get what we wanted . Still thinking ..
McGowen will build it !

I have the Dies and Brass right now .

Rum Man

 

[J E Custom]

Being a Big RUM fan and building wildcats off the cases. they are limited to around 112 grains of powder unless you go hog wild and push the case to it's Max volume (About 118 to 119 grains). Normally they have about 103 grains of capacity and if this is the plan, 270 to 300 grain bullets are about ideal. IF you AI it, you may get the performance from 325 grain bullets.

In order to use the 350 class of bullets you will need to go with something like the 378 Weatherby case for more capacity in my opinion.

The 300s may not have have the BCs of the 350 but the added velocity will make up any differences.

As to free bore, the RUM comes with a generous free bore of .175 with a .464 to the lands with secant ojive bullets. If a single shot, You wont be limited to mag length of the Remington and could look for a single shot action that Is much stronger.

I would also recommend that you have Dave Manson cut your reamer with the desired free bore to avoid having to use a throater on a standard chamber I find that I get better accuracy if everything is done with a custom reamer at one time.

Just some thoughts for your new build.

J E CUSTOM

 

[Doublezranch]

I can still remember the day I bought my 375 RUM. It completed my set of RUM's and it was a glorious day. I quickly fell in love with the caliber and have done lots of testing. Below is a thread on the 320 CE Bullets. The gun also loved the 350 SMK. I'm headed a different direction now with my 375 RUM. It's time to rebarrel and I like to have my plans in place for what I expect it to do when it's finished. Longer barrel, lighter bullets, and speed. J E, you up for the challenge?

https://www.longrangehunting.com/threads/finally-time-to-test-the-375-rum-and-the-320-ce.140162/

 

[yorke-1]

Just completed a 338 edge build on a r700 la. It has a hells canyon CF barrel, wyatt's mag extender, ejection port opened, and a manners thumbhole stock. Gun shoots a 300 gr Berger sub .5moa @ 2820 fps. I'm very certain it will smack elk near and far. Could shoot a 250 Berger @3100+.
The best part is the gun touches the scales at an even 10# and is easy to shoot. Not sure what the 375 rum would do better.

A 375 will do the same thing, just with a bigger, heavier bullet.

 

[Will Gray]

I have a 300RUM a 338EDGE and a 416/300RUM so now am thinking about a 375RUM: that would fill the RUM spectrum. Nothing like a project!. Thinking of making it a Savage 110 thread so I can put it in my Mausingfield.. I put the 416 barrel on a 700LA but that fits the Mausingfield stock I have. Easy to swap from one to the next.

 

[biff's reloading]

I love the rum case. I have a 300, a 375, and am currently building a 475, all 3 barrels fit the same savage 112fsak small shank action. Already planning my next one. It'll be a 416 on its own action for long range work, not a carry gun like these 3.

I think the 375 can do the 350s just fine. Maybe as big a bite as it can chew, but it'll do it well. I like the 300s

Since you are building from scratch, I'd suggest maybe looking at the 416. Those 400s really haul the whap a long ways.