Home Forums Hunting & Shooting Ask The Gunwriters 375 H&H improved

I often get asked why the “improved” version which I own. The short answer was it cost less than half of the not-improved 375. I was going through some old magazines and I found an article in the Rifle Number 30 dated Nov-Dec 1973 why people improved this cartridge.

The author wrote that the improved version gets a gain of 400 fps with either bullet weight (270 & 300). Meaning a 4,200 foot pounds gain in energy or a whopping 34 percent gain —— what he wrote.

It’s in writing, therefore it is true.

But what does 400 fps get you but more range? Energy doesn't kill. Bullets destroying tissue and causing cessation of brain function is what kills.

From what I've read over the decades, just about any "improved" cartridge will get another 400 fps over the "parent" cartridge!

You just have to be able to "read" pressure signs....

Who was the author of that gem?

Hey, when you pay to have an improved chamber cut, you've got to get the promised performance increase or the money wasn't well spent Load 'em up boys!

John Williamson wrote the article. My mind is slipping, but 4,200 ft-lb more energy is simply amazing, when that’s about what factory ft-lbs are (I think) and all because of straight walls and sharp shoulders.
I guess it’s because the new case is more efficient.

Saturn Custom Rifles from here in my neighborhood used a 45 degree shoulder and almost no taper. They also used 1/14" twist barrels in 25, 27, 7mm, and 30 cal rifles and a lot of jump.

This is how they got the blazing speeds. I had both a 7X57 ICL Tortilla and a 25/270 ICL Ram. They were beautifully made rifles on FN Supreme actions and in excellent wood. They shared the shortcomings of the need for speed. I had to brew up hot loads with light bullets to get them to shoot and not keyhole. When they were real fast with light short bullets they were one-holers.

The 25/270 ICL clocked 100gr bullets at nearly 4,000 fps. Brass didn't last long due to expanded primer pockets.

So...the "improvement" had a lot to do with Blue Pills.

Confused here ,are you saying 4,200 ft-lbs more energy over the standard 375 H&H?















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Sounds a lot like the 6mm Atlas I had way too much fun with way back when...

Yeah, there have benn a LOT of claims about magic shoulder angles, etc., over the decades.

But a few years ago I contacted the head ballistic techs at several piezo pressure labs, asking whether they'd encountered any magic velocity results from different case shape. ALL gave me an emphatic NO: The same powder capacity resulted in the same pressure/velocity, no matter the case. But they did say they found shorter, sharper-shouldered cases did tend to result in more consistent pressures and velocities

In fact, Charlie Sisk ran an experiment which I reported on in HANDLOADER years ago. The .300 H&H and .300 WSM have very similar powder capacities, and he ran strain-gauge, velocity and accuracy tests with a 26" heavy barrel he chambered in .300 H&H in his indoor 100-yard range.

Then he rechambered the same barrel in .300 WSM, setting it back a little for the shorter cartridge--but keeping the throat-length as close to the same as possible. Not only did the same powder/bullet combinations get just about the same velocity and pressure, but the same combos tended to result in the best accuracy.

This article was reprinted in one of my books.

If he is it means 8500ftlbs from an improved 375H&H. lol. 460 weatherby power.

Also thats a 100%, not 34% gain.

And a 400fps gain gets you about a 60% gain in energy , not either previous figure of 34 or 100...

No article could be that gooned up , surely.

Oh, I've read some great fiction on how much velocity can be gained by "improving" a case. Though much of the time it involves comparing the velocity of factory ammo with filled-to-the-gills handloads, especially with cartridges that have pretty low SAAMI pressures....

That's what has kept me from Weatherbying mine.
If the 350's don't go fast enough I can shoot 300's.
If the 300's don't go fast enough I can shoot 270's or 260's or 250's or...

It's called a 378 Weatherby..

That was what was written in the article - 4,200 more ft-lbs in energy! However, the charts he had shown wasn't as impressive.

I'm just bubbly that I have a "Big Enough" cartridge rifle to handle any ferocious beasts that might come onto my yard here in Northeastern South Dakota!

I had a man come into the shop looking to buy a new rifle. His old rifle, a 270 Ackley Magnum, was about worn out and he wanted to replace it with something with similar performance. I showed him a Remington 700 in 7mm Mag while he told me what a flat shooting rifle his 270 mag was. "Only drops 7" at 600 yards", he told me.
"Oh, really", I replied.
"Yep. I know because I shot an elk at 600 yards and only had to aim 7 inches high to hit right where I wanted to".
"Well, that's really something", I said, tactfully.
He looked the Remington over for a bit and decided he would take it. I told him it would serve him well but I couldn't swear it would match the performance of his Ackley. He gave me a knowing look and smirked a little. " I didn't really expect it would", he said with a wink.
I rechambered a Ferlach 375 H&H to 375 Improved for a guy who had heard the improved cartridge would push 300's to the same velocity you would expect from 270 grain in the standard cartridge. He was bound and determined to accomplish this so he loaded it up to where he was pushing those 300 grain bullets over 2700 fps. He started getting some misfires and brought the rifle in for me took look over. He had set the lugs back to where he had close to .015" of head clearance. I replaced the action for him and recommended he moderate his expectations just a little. GD

Plus, it wasn’t written on the net so it has to be true 😁

I think that gaining 400 fps is pretty optimistic! I’m not timid about pushing the limits a bit……but, I’m not getting 400 over a standard .375 H&H. memtb

Wasn't this done with the 375 Weatherby? I've tried an 378 Weatherby and it's not fun in a little rifle. Now I have a Ruger 375 Alaskan and it's practical and only recently acquired an 375 h&h in another rifle.

I'm not a gunwriter but don't the longer tapered type cartridge have a better feed geometry? Old cartridges like the 7x57, 8x57, 30-06, 300h&h, and 375 h&h have an shape that makes for slick reliably feeding. Wouldn't feed and extraction reliability Trump any bit of velocity gains?

If you are tempted to run a reamer into your very nice condition pre-64 375 H&H, I’ll be happy to exchange mine with your stock 375 and you won’t have to kick in much money.