375 RUM 350gr. Bullets?

[JMJ888]

Have just finished up my 375 RUM build the way the cartridge should have been originally introduced. As a lefty I am a bit limited but was able to find a LH M70 CRF in 300 Win and have my smith convert it. Ended up with a #6 Krieger barrel finished at 24” with Sunny Hill bottom metal and restocked in a nice piece of Turkish by Al Lind. Swaro 1.7-10 sitting in Talley QR adds a lot of versatility on optics and dummy rounds feed through it like it was designed for it. Gun is a bit heavier at 10.9lbs but extra weight offsets the recoil and makes it fairly comfortable.

Had the rifle throated with 350gr Barnes TSX’s at about 3.580” in mind or even the 350 PP Woodleighs, but 300gr TSXs will work fine if my load development doesn’t work as planned. The main goal for the rifle is to mimic the classic 375 H&H 300gr 2500-2600fps “all around” combo ballistically, but with 50gr. more bullet weight putting it on par with the 416 Rigby. Kind of a “one rifle for all” concept.

Has anybody done any development with the RUM/350gr. combo? Quickload is pointing to RL26/VVN560/MRP/7828 SSC for higher velocity (2550-2600) and H4350/H4831SC for lower end 2475-2500). I have N560 and H4350 on hand and will likely start there but wanted to see if anybody had notes to compare first.

 

[Philip Glass]

Very interesting

 

[Wyatt Smith]

A 350 at 2500. Man that sounds good! Think of the sectional density

 

[Forrest Halley]

Think of all the borerider bullets for the Cheytac you can use...holy Christmas! What was the twist? 1:10?

 

[bruce moulds]

the only consideration is how will the bullets perform terminally at those velocities.
there is no doubt that the barnes will do well as long as the twist is sufficient to keep it nose first in flesh and bone.
the woodleighs might be unknown, and be in the same boat as my 9.3x64.
most 9.3 bullets are meant for x62 and x74 velocities, including the nosler partition, and leave much to be desired when driven harder.
swift etc are excellent.
375 bullets could well be designed for h@h speeds, and be overstressed in a rum.
only time will tell?
an interesting bullet to try on plains game in the rum might be the 300 gn sierra boat tail driven hard.
it would shoot flat.
bruce.

 

[matt85]

a 350gr bullet will not perform as well as a 300gr bullet on game. the only reason to use a 350gr bullet over a 300gr bullet would be the higher BC for long range shots (400+ yards). a problem the 350gr and even the 300gr TSX will have is traveling in a strait line when inside an animal. expanded bullets of greater length are more likely to tumble inside an animal which will change the bullets course and could lead to missing the vitals on less then perfect shots.

for close range dangerous game id take a 235gr TSX pushed to 3000fps over a 350gr TSX at 2500fps any day! most people are too stuck in the past to use lighter mono-metal bullets so a happy medium would be to use the 270gr TSX pushed as fast as you can.

-matt

 

[bruce moulds]

matt,
they will only tumble if spin rate is too low.
they do however require more spin than shorter bullets.
bruce.

 

[JMJ888]

It is a 12 twist barrel which is sufficient for the 350s. Faster twist doesn’t become necessary until you get up in the 375-400gr monos.

The length of the 350gr TSX and 3.6” M70 mag length restriction limit my powder a bit but I think 2550-2600 is achievable with the N560. The 350 Woodleighs are a shorter bullet than the Barnes freeing up a bit of powder space but have a 2500fps impact velocity ceiling so don’t really gain any benefit from more powder capacity/speed.

I think the ideal action length would have been my CZ550 but I went big with that one and had AHR convert it to 500 A2

 

[matt85]

the twist rate has nothing to do with what im talking about. twist rate primarily affects the bullet in flight, im talking about how the bullet performs post expansion inside an animal. a mushroomed bullet with a longer shank is more likely to tumble then a mushroomed bullet with a shorter shank. the book African Dangerous Game Cartridges by Pierre van der Walt makes some interesting points on this and it makes perfect sense.

which one of these shapes would pass through water in a strait line better:

1. -]
2. ---]

the shape with the longer shank is going to be far my likely to flip around and travel shank first.

-matt

 

[JMJ888]

Fair point Matt but I would like to do some testing of my own with the bullets to see how they perform. Will do quite a bit on our feral pigs here in Texas along with other methods and see what happens for grins.

Still curious if anyone has notes on loading the 350s?

 

[bruce moulds]

matt,
2.--- has a longer overturning moment than 1.-.
hence the need for a faster twist for the same stability.
the same thing even happens in air at high altitudes compared to sea level as happens in flesh.
more resistance on the nose makes for a higher twist requirement to stay nose on.
whatever, the o.p. can always go back to shorter bullets if necessary.
copper bullets are always longer than lead cored.
another question to ask is will the really heavy barnes bullet from a rum overpenetrate a buff?
bruce.

 

[TOBY458]

a 350gr bullet will not perform as well as a 300gr bullet on game. the only reason to use a 350gr bullet over a 300gr bullet would be the higher BC for long range shots (400+ yards). a problem the 350gr and even the 300gr TSX will have is traveling in a strait line when inside an animal. expanded bullets of greater length are more likely to tumble inside an animal which will change the bullets course and could lead to missing the vitals on less then perfect shots.

for close range dangerous game id take a 235gr TSX pushed to 3000fps over a 350gr TSX at 2500fps any day! most people are too stuck in the past to use lighter mono-metal bullets so a happy medium would be to use the 270gr TSX pushed as fast as you can.

-matt

See the blown apart 270 gr TSX that I pulled out of a Lioness weighing around 250lbs. Missing all it's pedals. Muzzle velocity was 2750 fps. The other two bullets came from a Wildebeest at much further distance, once the bullets had slowed down. No way I would trust a 270 gr TSX on a buffalo, if the impact velocity was more than 2500 fps. Much less a 235 gr TSX at 3000 fps! I also witnessed fellow AH member @Ridgewalker shoot a Warthog at around 30 yards away with the 235 gr TSX and it blew up on impact! Didn't even make it into the chest cavity. Those lightweight bullets may work sometimes, but on Buffalo, give me 300 grains or more.

 

[BeeMaa]

Any thought of using Swift A-Frames in 300 grain?

If you are set on 350 grains...
Woodleigh has 3 bullets offered, Protected Point SN, Heavy Duty RN SN and FMJ.
You should be able to make at least two of those work at the intended velocities.

 

[TOBY458]

This is the ENTRANCE wound of a 235 gr TSX 375 bullet, fired at 3000 fps. Impact distance 30 yards. The Wart hog had to be shot again with a pistol to finish it off. Bullet completely blew up on impact. What do you think it would do on a Buffalo shoulder, or even a Buffalo rib?

 

[colorado]

I load the Woodleigh 350g HD softpoints to 2550 out my 375 Weatherby. Awesome bullet, designed for those velocities. Only shot paper with them so far. Got my brown bear with a 300g A-Frame at 375 H&H velocities (was using 375 H&H factory ammo). Bullet traversed an 8 1/2' brown bear diagonally and still weighed 299.5 grains

 

[JMJ888]

Any thought of using Swift A-Frames in 300 grain?

If you are set on 350 grains...
Woodleigh has 3 bullets offered, Protected Point SN, Heavy Duty RN SN and FMJ.
You should be able to make at least two of those work at the intended velocities.

I’m not set on the 350s but ideally using that as a starting point to test and tinker. I have 350gr TSXs on hand and have the 350 Woodleigh PP’s on backorder so starting with the Barnes for now.

On paper, the Woodleigh will likely offer the best all around solution...it is the shorter bullet at 1.408” versus 1.493” and 1.691” for Barnes 300 and 350 TSX. Less bullet encroaching on case capacity and can easily get in the 2500-2550 range with one of the Hodgdon Extreme powders at sub 60k pressures which keeps it on the edge of the recommended impact velocity of 2500 from Woodleigh. Good all around temperature stable Africa load.

In the meantime and more for academic purposes I want to push the 350 TSX as hard as I can with 2600fps being the ideal goal. Will likely result in a max load at higher pressures that would be reserved for feral hogs and such unless it performs better than I expect.

I have a 375H&H so will likely keep it reserved for the 300gr.

 

[TOBY458]

I’m not set on the 350s but ideally using that as a starting point to test and tinker. I have 350gr TSXs on hand and have the 350 Woodleigh PP’s on backorder so starting with the Barnes for now.

On paper, the Woodleigh will likely offer the best all around solution...it is the shorter bullet at 1.408” versus 1.493” and 1.691” for Barnes 300 and 350 TSX. Less bullet encroaching on case capacity and can easily get in the 2500-2550 range with one of the Hodgdon Extreme powders at sub 60k pressures which keeps it on the edge of the recommended impact velocity of 2500 from Woodleigh. Good all around temperature stable Africa load.

In the meantime and more for academic purposes I want to push the 350 TSX as hard as I can with 2600fps being the ideal goal. Will likely result in a max load at higher pressures that would be reserved for feral hogs and such unless it performs better than I expect.

I have a 375H&H so will likely keep it reserved for the 300gr.

I used 300gr TSX bullets from a 375 H&H on 3 large Water Buffalo in Australia. Velocities were running 2450fps from my short barrelled Sako. Penetration was spectacular! Bullets were perfectly mushroomed and most ended up just under the hide on the opposite side. Sometimes having traveled through both shoulders. I would imagine that the 350 gr TSX at 2600fps would do even better. Definitely no need in more velocity than that. Maybe even step it down to 2500fps for low pressure.

 

[Forrest Halley]

What was the intended purpose of this build? It looks like you're essentially running a beltless H&H? Is it really that much of an improvement to grab that .050 SD with 50-100 fps? It appears like apples to apples H4350 the RUM isn't as efficient as the H&H.

 

[JMJ888]

What was the intended purpose of this build?

Laid out the purpose of the build in first message. The main goal for the rifle is to mimic the classic 375 H&H 300gr 2500-2600fps “all around” combo ballistically, but with 50gr. more bullet weight and higher SD putting it on par with the 416 Rigby. Kind of a “one rifle for all” concept. Means on a two rifle safari the RUM could function for plains game and DG backup rifle to a 458 Lott/500 A-square. H&H could do the same.

Is it really that much of an improvement to grab that .050 SD with 50-100 fps?

That’s why I built the rifle...best way to test a theory is to do it. If I’m wrong a rebarrel is pretty easy.

It appears like apples to apples H4350 the RUM isn't as efficient as the H&H.

Efficiency is never the goal of any RUM based build. Every extra grain of powder gives diminishing returns...I accepted that up front.

 

[matt85]

What do you think it would do on a Buffalo shoulder, or even a Buffalo rib?

i know a PH who has used 200gr .375" GS Custom bullets in a 375 H&H on buffalo. he said it provided some of the most spectacular DRT kills.

-matt