I have a CZ 550 Safari in 375 H&H with a rough spot in the chamber. I am sending the rifle into CZ to see if they can remedy the situation.

Anyway, I've thought long and hard about this and I'm just about at the tipping point of turning my H&H into a 375 Wby. Why? Just because.

Here is the question, and mind you, it may be a dumb question: If I have a custom shop ream the barrel of my 375 H&H to a Wby, will I be able to use factory ammo?

See, I want to have at least a couple of boxes of properly stamped ammunition but seeing as how the 375 Wby was mainly a wildcat cartridge and only has been chambered in a few production rifles, I am wondering if the reamer that the gunsmith might have will be of the same dimensions as the currently available loaded ammo and unprimed brass that is out on the market.

Again, if that is a dumb question, let it slide. I've never fooled with wildcats other than a cousin's 243 AI and my experience with that is practically nil. And seeing as how there is actually loaded 375 Wby ammo on the market, I would hate to plunk down a bunch of cash for some boxes only to findout that they will not fit properly in the chamber. I suppose this question would be best posed to the actual gunsmith that is going to do the work but I thought I would float it by you guys first.


Landrum

send to cz

if you have it recut, get dies from your chamber, or demand a spec chamber

yes, you can use 375HH and fireform it

i would't bother.. WORST case is that i would set back a thread and rechamber, and bed the rifle....
"near" wildcats are more frustration then real ones

quote:

Originally posted by Landrum:
I have a CZ 550 Safari in 375 H&H with a rough spot in the chamber. I am sending the rifle into CZ to see if they can remedy the situation.

Anyway, I've thought long and hard about this and I'm just about at the tipping point of turning my H&H into a 375 Wby. Why? Just because.

Here is the question, and mind you, it may be a dumb question: If I have a custom shop ream the barrel of my 375 H&H to a Wby, will I be able to use factory ammo?

See, I want to have at least a couple of boxes of properly stamped ammunition but seeing as how the 375 Wby was mainly a wildcat cartridge and only has been chambered in a few production rifles, I am wondering if the reamer that the gunsmith might have will be of the same dimensions as the currently available loaded ammo and unprimed brass that is out on the market.

Again, if that is a dumb question, let it slide. I've never fooled with wildcats other than a cousin's 243 AI and my experience with that is practically nil. And seeing as how there is actually loaded 375 Wby ammo on the market, I would hate to plunk down a bunch of cash for some boxes only to findout that they will not fit properly in the chamber. I suppose this question would be best posed to the actual gunsmith that is going to do the work but I thought I would float it by you guys first.


Landrum

Nothing wrong with the .375 Wby. If the "spot" is in a area that the Wby reamer will clean up I would not hesitate 1 second & shooting factory .375 H&H in the Wby you will only loose 10-20 fps over firing it in a .375 H&H & I gained 200-300 fps over the H&H with the Wby

Always wonder how 8% capacity would give 9% velocity. Pressure? Freebore?? Wby selling tactics??? Federal does lists a load within 10 of what Wby list for the 375Wby

Other option would be simply the 375H&H AI same capacity as the 375Wby.

The .375 Weatherby is a CIP spec-ed cartridge.
No worries.
The date on the CIP spec is May 15, 2002.

Weatherby revived the .375 Weatherby for 2001.
Dave Manson makes a reamer that conforms to the 2001 Weatherby throat.

It is long past a wildcat, and has not been one since Roy Weatherby proprietized it right around the end of WWII: 1944-1945 development.
Roy must have been 4F.

It has been factory loaded for over a half century.

It will clean up the .375 H&H chamber.

You can shoot standard .375 H&H ammo in it, with good accuracy and Doctari-speed.

Weatherby factory loads will deliver 2800 fps with a 300-grain Nosler in a 26" barrel.
You can do that with handloads of H4350.

With the CZ box and 25" barrel you can easily match that with handloads.

I have a CZ 550 Magnum Hogback that was rechambered to .375 Weatherby, as well as a Winchester M70 Classic Stainless, and a Whitworth Mark X, .375 Wby.

I sure could use a bespoke full custom pair of .375 Wby rifles next. One walnut and blue and heavy, and the other stainless-synthetic and 7 pounds dry weight., both will have 1:10" twists so Gerard will not criticize the choice of 300-grain HV and FN.
1:12" is actually fast enough, but don't get Gerard started on that again.

My Whitworth has the 1945 throat, long and sloppy. The other two have the 2001 throat.

Get it reamed with the CIP 2002 or Weatherby 2001 spec reamer. They are the same.
The new, throat with only .3700" length of parallel-side freebore is the perfected one.

Standard reloading dies have been around for a long time. RCBS and Redding I have used and recommend. They are the same for the 1945 version or 2001 version, only chamber throat differences are involved.

The .375 Weatherby is the most practical big game rifle ever.
The only one you really need.

I've never owned a .375 Weatherby but looked at loading data years ago.....and to the best I can recall the weatherby .375 stood marginally over the .375 H&H.....and I mean 100 FPS or so....I always wondered why anyone would go that route for such little gain.....then Weatherby introduced the .378 and wow....what a gain....but even the thought of shooting it hurt me!...LOL

I'm truly of the opinion that loaded to the same pressures the gain in velocity of the weatherby .375 over the .375 H&H is minimal.....100 FPS or less!

Don't believe the jealous BS about little gain of the .375 Wby over the .375 H&H.
Lightest weight bullets in .375 gain little, O.k. 100 fps there, with 235-250-grainers.

300 to 350-grainers grainers get 200 to 250 fps more in the .375 Wby than the .375 H&H, at same pressure.

The heavier the bullet is, the more the .375 Wby beats the .375 H&H, with the same bullet.

The faster powders required with the lighter bullets just peak out in pressure too soon.

The slower powders with greater capacity of the .375 Wby gives it a quantum leap over the .375 H&H.

Not a tiny little quantum.
A quantum of solace, worthwhile.

What I do not believe is the pixie dust heavy magnum loads for the .375 H&H.

Whatever quantum of solace the .375 Ruger has over the .375 H&H, the .375 Weatherby has about double that.

Make sure a Weatherby spec reamer is used which will provide the longer throat. You will be able to use factory ammo with that setup and have no worries about pressure.

Ken....

.375 Weatherby, I have a .375 Weatherby, a 1954 Sako, rechambered by Simmons Guns in Olathe, Ks. +1

I have not loaded for the 375Wby I have loaded for the 375AI the capacity being basically the same. Capacity gain was around 8% my velocity gain was around 2% or 50-70FPS. I do find it interesting that Remington list the velocity of the 375RUM as 2760 while loaded to 65,000 which is hotter than the WBY or H&H. The RUM has twice the capacity gain and additional pressure over the 375Wby.

Not saying there is a thing wrong with the 375Wby. Just saying if I needed to clean up the shoulder I would do an AI and be happy.

The new .375 Weatherby freebore of 2001 (0.3700" long parallel-sided) is actually about 1/2 as long as the 1945 version.
2001 spec is perfection.

The .375 RUM throat has a much shorter throat than even the new .375 Wby.

Swift A-Frame bullets seem to jack up pressures and result in lower velocities to stay in pressure range than some other bullets.

Weatherby is right on with their factory velocity.
Remington factory ammo actually was higher than what they claim in my own rifles for .375 RUM.

Both cartridges with factory rifles and factory ammo will do about 2800 fps in a 26" barrrel.

I have shot these a lot.

One of my .375 RUM rifles is a CZ with 23" barrel and it has been re-throated with .375 Weatherby throat.

The .375 RUM reamer will not completely clean up the .375 H&H chamber like a .375 WBY will ... believe it or not!

The .375 Weatherby was first and best as an improved .375.
All the rest are imitators of the .375 Weatherby.

From my experience with both the 375HH and 375WBY I have to agree with RIP. I seem to reap the bennefit of slower burning powders (4350, 4831, RL19, RL22) with the heavier bullets in the 375WBY.

I will never understand why some on this board have such loyalty to a particular cartridge regaurdless of its storied past. They are tools, nothing more. They have no compassion, loyalty, or remorse, and they will not love you back. When Ruger gave us a new 375 mag some of you here seemed to take it as a personal insult as though Ruger had just slapped you're child.

The 375HH is a wonderful cartridge and has done it all but the 375WBY beats it by 200fps or more with the heavier bullets.

I wouldn't hesitate to rechamber a flawed 375HH chamber to 375WBY.

Yes, you will be able to use factory ammo. Use your local gunsmith.

quote:

Originally posted by RIP:
Don't believe the jealous BS about little gain of the .375 Wby over the .375 H&H.
Lightest weight bullets in .375 gain little, O.k. 100 fps there, with 235-250-grainers.

While I've not loaded for the H&H, I find most max loads for 250 grainers to be listed in the 2750-2800 fps range. In my Weatherby, my pet 250 gr. load runs right about 3060 fps. Seems to be a pretty significant improvement on the light bullet end, as well.

Were it not for the fact that there is a slight flaw in the chamber of my 375 H&H I wouldn't even be contemplating this project at this point. And if CZ fixes it to my satisfaction, I'll leave it as an H&H for now. However, I have always been drawn to the 375 Wby and one day I will have one.

Landrum

quote:

Originally posted by Landrum:
......... I have always been drawn to the 375 Wby and one day I will have one.

Landrum

Same deal with me. I'm extremely happy I made the move.

Strut10,
I don't doubt your result.
What are the specifics on your 3060 fps with 250-grainer?
Brass?
Primer?
Bullet make?
COL?
Powder charge?
Barrel length, make, twist?
Freebore length of your chamber?
Approximate temperature?
Altitude, barometric press, and humidity not required.

Some claim the .375/265-grain GSC HV will go 2900 fps in the .375 H&H.
If GSC made a 250-grainer it would probably do 2960 fps and we are back to 100 fps difference.

Maybe I never milked it for all it was worth with the lighter bullets?
Maybe the .375 Wby is 250 fps faster than the .375 H&H with all bullet weights?
That is a nice thought.

Always difficult to compare two different rifles of different chamberings or even the same chamberings, as there are "fast rifles" and "slow rifles" in any chambering, and rifle and load variables galore!

The .375 H&H is 96 years old, a wonderful old hunting hound, but has never learned any new tricks.

The .375 Wby is 63 years old, and is no puppy in the litter of .375's, and certainly no wildcat!

It was taught a new trick in 2001 and is even better now than it was as a puppy in 1945.

quote:

Originally posted by RIP:
Strut10,
I don't doubt your result.
What are the specifics on your 3060 fps with 250-grainer?

Lawyer talk:

This load functions safely in MY rifle. I assume no responsibility whatsoever for what happens if anyone else feels he can just throw a few of these together and try them in his gun.


Brass?.... Weatherby (new style)
Primer?.... Federal 210M
Bullet make?.... Sierra Game King
COL?.... 3.595"
Powder charge?.... 92.0 gr H-414
Barrel length, make, twist?.... 26" factory Browning (twist??)
Freebore length of your chamber?.... .3700" (new Manson reamer)
Approximate temperature?.... 80 degrees or so
Altitude, barometric press, and humidity not required. .... +/- 1300 FASL, (pressure??), probably 70-80% humidity

I GOTTA TRY THIS:

[QUOTE]Originally posted by Strut10:

3060 fps with 250-grainer:
Brass?.... Weatherby (new style)
Primer?.... Federal 210M
Bullet make?.... Sierra Game King
COL?.... 3.595"
Powder charge?.... 92.0 gr H-414

/QUOTE]

And I promise not to hurt myself.

RIP,

Many years ago I got 3050 fps from my 375 inmproved using WW 760 and 250 grain Bitterroot.

This from a 22 1/2 inch barrel.

I did not like 760 (or most other double base powders) though because if you changed one component, primer, brass or bullet, no telling what pressure would do.

H414 is a ball version of IMR4831 (at least with some components) so it might work????

Especially from 26 inch barrel.

I love the improved and weatherby case.

Andy

quote:

Originally posted by RIP:
I GOTTA TRY THIS:

quote:

Originally posted by Strut10:

3060 fps with 250-grainer:
Brass?.... Weatherby (new style)
Primer?.... Federal 210M
Bullet make?.... Sierra Game King
COL?.... 3.595"
Powder charge?.... 92.0 gr H-414

And I promise not to hurt myself.

Interested to see how it runs for you. Please let me know. I will go look up the actual range sheet from the load to give you the actual, exact numbers. I believe 3042 fps avg @ 15 feet, IIRC.