Guys,

I don't have access to chronograph right now. I shot my 375 WBY yesterday with a load I had not tried before and it gave excellent accuracy. The load was a 270 TSX and 89 gr H-4350 from a 24" barrel. Anyone care to take a guess on velocity? My 300 gr NF softs chronograph at 2765 fps with 86 gr of H-4350 from the same rifle if that helps. I'm hoping to push 2900 fps with 270 TSX. Any suggestions?

Mark

My WAM guess -- 2800+ (fps). I use H&H max loads as a starting point for my rechambered Brno. You are already 10 grains past that in your rifle. (2700 fps per Hodgdon data in old Load Data book, in H&H.)

FWIW, I have never approached 2900 fps. 2865 with 250 grain TTSX and 78 grains RL-15 is my closest load. (Got faster with 235-grainers, but that's a far cry from 270's.)

In my 25" barrel .375H&H I am getting 2830 FPS with a max load of RL 15 and 270 Gr TSX. I would think you could get 2900 or pretty close to it out of the Weatherby without to much trouble.

Mark ; were you at max pressure with the 89 gr 270 gr load?
I would bet that you are nipping at the heels of 2900. . Too bad Barnes didn't make a 270 or 300 gr TTSX.
Get the G1 bc up to at least .5 . Oh well CEB does.
That is some very impressive velocity.

CTF,

I actually shot 90 grains with no ultra flat primers or bolt lift in 90 degree temps but group opened up notably.

Mark

Mark

3 shots : 2880, 2870, 2890 fps. Pulled three 270 Hornady from 76 grain RL-15 load, dropped 89 grains H4350 in and reseated. Primers look the same as those from RL-15. (Took Doubless to the range yesterday, when it WAS NOT raining, unlike today. He tried my .375 Wby off sticks and then a couple with the .416 Rigby we wanted to check cast boolits with.) The target is from yesterday and I believe the three above the bull are from today, same target. Not many shooting of a Wednesday or a rainy Thursday, so I snuck in with the Pro Chrono to get other then WAM numbers for you.

Cheers!

Barry

My 78 grains RL-15 load with 250-grain TSX -- 2825 fps.
My 76 grains RL-15 load with 270-grain Hornady -- 2660 fps.

If accuracy is indeed good, that's a whale of a good load you've got, I'd say!

I bet it is close to 2800 +. I will get a real run later.

From Barnes - but for 375 RUM

Bullet Weight: 270 gr Case Trim Length: 2.840" S.D. 0.274
Bullet Style: TSX FB Primer: Fed GM215M B.C. 0.326
COAL: 3.575 Barrel Length: 24"
Case: R-P Twist Rate: 1:12"
Charge Velocity Charge Velocity Load
Powder (grains) (fps) (grains) (fps) Density (%)
 H4350 88.0 2767 96.0 2959

Being a .378Wea man I actually envy the .375RUM a Little.
I get surprised everytime I see someone posting their velocity results with their .357RUM. They are scary close to .378Weatherby ballistics. I know the .378 has the edge but the RUM gets so close the difference is barely visible once passing the 100yard mark for any bulletweight.

Mark I got 3050 fps with the 250g A-Frames. The factory 300g Partitions clocked out of my 375 Weatherby with a 24" barrel at 2750 fps. I think 2900 fps with a 270 TSX should be doable.

Intriguing...

You're 1 grain over the max load listed on the Hodgdon load data site.

Their max of 88gr shows
88.0
2,787fps
52,800cup

So you're probably just cracking 2800fps?

What is your Cartridge OAL?

Coincidentally Load From a Disk has a nanny algorithm built in, H4350 is not an available choice for their computer modeled loads.

Anyways I find this nerdy stuff fun. Best of luck to you.

I found one of my old Barnes manuals today. I'll check in the morning and list their loads.
I remember a Remington 700 I had in 375 HandH
I distinctly remember when developing a 270 gr X bullet load that 76 gr of Rl15 gave EXACTLY 2777 fps. First shot was 2776 then 3 in a row 2777 . I thot the chrony was malfunctioning. I shot something else over it. I think it was my SKS, 7.62×39. It recorded a commensurate velocity for that rifle. Then I shot one more 375 , 270 gr load and got 2778 fps. . I later reduced that load by 1 grain as I thot it a schosh too warm.

My point being that the Whby, Ackley, ect. Get at least 100 fps on the H and H. With the correct powders so imo 2900 should be close to what you can get.

Unfortunately the one 375 Whby I have access to is over 600 miles away. So I don't really have access to it at the moment. Sorry.

Shot 10 more, Mark, and the accuracy was poor. However, TSX/TTSX would probably do better. (I have too many other loads ready to go, but it was fun to check. Thanks!)

Ya, so I'm looking at the Barnes #3 manual right now. I remember why I was so disgusted with this manual. They show faster velocities for the HandH than they do for the Whby. Pretty useless information!
But with 414 and the XLC they show 2888 fps but with H4350 they show 87 gr only yielding 2819 fps. Maybe they had a weak lot of H4350.
Sorry I'm not much help.

Tried Quick Load, but it suggested this load was way over maximum, but Weatherby guns have abundant free-bore making QL likely unusable.

Nonetheless, QL shows 84.3 grs of H4350 giving 2887 fps at 65000 PSI. 89 grs gives 79,000 PSI and 3045 fps.

I think you need a chronograph.

From my "Caliber Files":

My CZ 550 Magnum 25" .375 Wby may be a little slower than my Winchester M70 24" .375 Wby, both are rechambered .375 H&H factory rifles,
done with the same reamer, with newest C.I.P. standard throat that Weatherby revamped for 2001.

Or my lot of H4350 powder might have been slower than my previous lot ...

The GSC bullets may contribute to lower pressures and lower velocities than would be had with other bullets of greater bearing surface,
for a given powder charge.

Same scope setting for both loads. Two good loads below. No pressure signs, I could add more powder.

quote:

Originally posted by Ackley Improved User:
Tried Quick Load, but it suggested this load was way over maximum, but Weatherby guns have abundant free-bore making QL likely unusable.

Nonetheless, QL shows 84.3 grs of H4350 giving 2887 fps at 65000 PSI. 89 grs gives 79,000 PSI and 3045 fps.

I think you need a chronograph.

The defaults in QuickLOAD are not accurate.

What does one use for start pressure of the 270-grain Barnes TSX bullet?
I used a SWAG of 4000 psi.

QuicLOAd default case capacity for the .375 Wby is 105.0 grains.
With Norma-made .375 Weatherby brass of factory ammo, the gross water capacity is 111.5 grains.
Max brass length is 2.860".
Arbitrary C.O.L. for my run of QuickLOAD below was 3.580", since Mark did not state it.
24" barrel as he stated.

Barrel tightness in the grooves and powder lot variations are the biggest unknowns in applying these simulations to our own rifles.

Certainly some free-bore can let off some pressure, but if you are getting high velocities, then you must be getting some high pressures.



From the propellant selection table:

H4350 Extreme does seem to be the velocity champ at 2916 fps for 88.4 grains of powder, a mildly compressed load (103%) and 99.8% burn.

RL-17 looks very interesting at 2908 fps for 86.1 grains of powder, a non-compressed load (96%) and 100% burn.

CIP max pressure for the .375 WBY is 4400 bar = 63,817 psi



RL-17 does beat H4350 for velocity when using the .375/250-grain TTSX in the .375 WBY, according to QuickLOAD.

I was getting 2950 fps with 270 grain TSXs and a pail full of H414 in a 26" Bevan King barrel and old 3/4" freebore.

The loads were high by every book but Nick Harvey's.

Various 300s went over 2800 with the same powder.

I sure am wanting a 375 WBY...I have been under the RUMs spell for a few years now, but always thought the WBY had its place.

Ed

Where I really started thinking about a .375 Weatherby was when Saeed posted that with his 300 grain bullets 2800 fps seemed to be the optimum velocity for killing buffalo. Naturally, recognizing that speed as the advertised factory velocity of a .375 'Bee my thoughts went down that road. Having a shot out H&H and a couple others that could stand some waking up didn't hurt. I still haven't put it to the real test, because the .45s have taken ahold of me. All things in time.

We have a Rem XCR II in 375 Weatherby we like it a lot. We can easily get 2750 fps with 300g A-Frames and still shoot 375 H&H when we want to all in a 7 1/2 lb rifle (weighed with scope, unloaded and no sling).

The ability to shoot factory H&H or any H&H handload that you can close the bolt on doesn't hurt either.

Absolutely, I used factory 375 H&H 300g Swift A-frames on my brown bear hunt Mark arranged for me. They worked great

I think we are rapidly closing in on the modern all around rifle. With the high bc 300 gr CEB bullets @2800 fps. That is over 5 k ft.lbs on muzzle energy and a flat enough trajectory for well over 1200 yard shots on deer and the ability to body slam a brown bear at the 20' range.
All with 1 rifle, 1 scope, ( 3-15 ×42- 3-18×50 ) and 1 load.

To me it don't get no better than that.

quote:

Originally posted by Cold Trigger Finger:
I think we are rapidly closing in on the modern all around rifle. With the high bc 300 gr CEB bullets @2800 fps. That is over 5 k ft.lbs on muzzle energy and a flat enough trajectory for well over 1200 yard shots on deer and the ability to body slam a brown bear at the 20' range.
All with 1 rifle, 1 scope, ( 3-15 ×42- 3-18×50 ) and 1 load.

To me it don't get no better than that.

Yep, I agree.

The Weatherby factory ammo with 300-grain Nosler Partition does about 2740 fps at 5-yard chrono for my 24" M70.
Correct that to muzzle velocity and it is over 2750 fps, and thus nigh on to 2800 fps for a 26" barrel, as advertised.

I can duplicate those factory loads with either 300-gr Nosler Partition or Sierra 300-gr GameKing,
using H4350 as powder.

RIP,

I gotta get out there with a chronograph but I think your charts are pretty close. I get a real 2765 FPS with the 300 NF in the 375 WBY powered by 86 gr. of H4350 shot over a new Ohler chrono so I don't think 2900 fps with the 270 TSX and 89 gr. of H4350 is unrealistic at all. I think I'd be happy to take on anything other than elephant with that load. BTW it also shoots near a half inch.

That old Barnes info as mentioned is ridiculous.

Mark

Mark,

Your rifle, loads, and shooting ability: "Aces."

Chronoraph would be nice.

I've used QL for many, many years - I think from about the time it was first available.

In my experience, QL works best with the defaults for the "common" calibers, such as 30-06, 308, 7mm Mauser, 8mm Mauser, and the like.

But, when you apply it to the "uncommon" calibers and to the less common caliber/gun set-ups, then it tends to be less accurate with the defaults.

Playing with the default settings (i.e., OAL, case capacity, shot start [initiation] pressure], and the mysterious "weighting factor") one can manipulate QL to provide almost whatever results you want. I stopped doing this with QL.

My approach with QL - that is, when dealing with an uncommon caliber and/or gun/caliber set-up - is to get some real chronograph/bullet/powder charge data, measure actual H2O case capacity; and, then adjust the defaults until QL begins to approximate these actual real data measurements.

Once you've achieved a "near match" one MIGHT be able to extrapolate to other bullet/powder charge situation for this same caliber/gun set-up.

Even then, QL should be used only as an approximation of reality.

Unless you have reliable real PSI measurements to correlate with velocity and powder charge, I don't believe the QL defaults can be precisely determined.

QL should not obviate the need for a chronograph and for reliable velocity measurements correlated with the presence or absence of excessive PSI signs.