Anyone have any experience with a .340 (or .300)Weatherby necked up to .358? I'm considering having one built on a stainless CRF action, 26 in bbl, synthetic stock for elk, moose, bear, etc.. Loads, Velocities? Recommendations? Thanks!

Other then the double radius shoulder, it would be essentially a 358 STW. There are a few members here that shoot the 35 STW, hopefully they'll chime in. You could also do a search for 358 STW, and see what's been posted in the past.

Thanks Paul. I don't want to fire-form brass, just simply neck up .340 Wby brass with no other changes. This is why I am not considering the STA. I'll research the STW.

Layne Simpson has a great article that you should read on the .358STA.

The 358 STA is not too far off from a 375 H&H. If you did have to fireform should not be that big of a deal since the dimensions of the rest of the brass besides the neck are very close. I was considering a 358 STA project myself and was going to make brass from 375 H&H brass for it. Check out the dimensions on a program, or check out ammoguide.com and set up a free membership. It has all kinds of cartridge measurements.

better yet, go to the gunsmithing forum, look up a post named "358 RUM" one person there uses 375 RUM brass, runs it through the sizer, and is done. here is part of his post. "Dan is right it is a 360 IMP.
Just got my 1999 Montana action last week.
Did find 360 IMP dies, bought some 375 Rum Brass ran them through the sizer die,seated a 250 Horn. checked measurements to a 360 Imp round and found them to be the same loaded OAL lenght is 3.6" so it fits the Montana action" Just another suggestion.

Different animal entire, gixxer. The RUM has a base dia of about .550" and the STA/Wby .511", so the RUM is substantially bigger.
I would agree with the others; the STA has more capacity than the H&H, essentially being a 375 Wby necked down, more or less. Or more precicely an 8mm Rem Mag Imp necked up.
It's an excellent round. And you can get brass, reamer and dies without having them custom made.
And in fact it's a wee bit longer than the 340.

understandable, just offering an opinion on an unbelted cartridge.

Thanks for the info, but I am set on the Wby case. RUM/STA is too much of a good thing IMO. Anyone else ever attempt the Wby?

my smith has a 358/378 reamer. i have watched a rifle fired in this caliber. with the brake on it was interesting. no brake, horrific.......
woofer

nyrifleman,

I have played about with the 358 STA quite a bit.

375 Winchester brass fireformed was only about 2 grains bigger than new 340 brass.

I often used 340 brass necked up and fired in the 358 STA.

I think you will find the 358 STA is much better for dies and reamers than a 340/358.

If I was doing it today I would choose the 358 RUM and just neck 375 RUMS down. That is going to do the 3000 f/s with 350 grainers with low pressure loads.

There is a poster here under the name of RIP who has a 375 CZ rechambered to 375 Ultra and it all functions so he could pass onto you wahtever is/was required for feeding. Obviously if his rifle is OK for 375 RUM then 358 RUM will be fine.

All you need for a 358 RUM is a gunsmith with a 300 Ultra reamer with detachable reamer. The throat/neck is cut separate. Similar easy deal for die makers.

The same deal will not work for 300 Wby reamer and 358 Wby because of the double radius shoulders. A correct 358 Wby die would not properly on a case fired in such a chamber.

Mike

I'd just get a 375Wby and be done with it! After shooting my own today I am more convinced than ever that it is better than anything else in this caliber/performance area.

I already own a .375 H&H from Empire Rifles stocked in a beautiful piece of English. I do not need the level of power a 375/378 Wby would provide. Let's focus here guys!!! .358 Weatherby? Anybody? Hello?

Honestly the 358 you propose will be at the same power level as your 375 H&H, only the recoil will be sharper. I'd expect 250 gr @ 3000 fps, and 270-280 gr @ 2800 fps.

Unless you can find a smith who has done it before, you'll have to fork out for the chambering reamer, and possibly a die reamer.

Thanks Paul. I've mulled all the reasons NOT to have one made, but I just WANT one. IF (A Big If) it will provide a noticable ballistic advantage over the 338 Win/358 Norma.

Apart from:

1) Just wanting a 358 Wby

2) Having that 35 power and a Wby shoulder

3) A series of Wby rifles and wanting to keep to the theme.

I can't see one reason for a 358 Wby over the 358 STA especially since if you don't want to fireform just neck up 340 Wbys, which is what I did in the 358 STAs.

Mike

So, nyr, you DO understand that the STA and the 340 are made from the same case, right?
When you say you're set on the 340 case, and that the 358 STA is too much, it makes me think you think they are different.
Same base dia, same belt dia, the only diff is that Wby uses that funny shoulder.
Long as you understand that, and that the STA already has reamers and dies floating around, as well as headstamped brass, then if you want to neck up a 340 to 358, go for it. I do believe you will be the first.

quote:

Originally posted by nyrifleman:
Thanks Paul. I've mulled all the reasons NOT to have one made, but I just WANT one. IF (A Big If) it will provide a noticable ballistic advantage over the 338 Win/358 Norma.

You'll gain about 200 fps over those. 338 win mag is 250's @ 2700, 358 N is 250's @ 2800 fps, and 358 STA or Wetherby will be 250's ~200 fps. So, you're trajectory will be flattened a tad, and add 30-50 yds to your no hold over range.

I personally have a 350 Rigby, all thanks to the bad influence of Mike375 It pushes 250's to 2700 fps. That makes it an honest 300 yd gun, which is as far as I'd shoot anything with it. I've heard the larger cased faster 358's have nasty recoil, which I don't doubt. If I want more gun, then I grab my 458 Lott, if I want flatter shooting, I'll get a 300 win mag.

With all that said, if you're a 35 fan (I am in a big way), and you want a flat shooting elk rifle, the bigger cased 35 shooting a 225 Barnes triple shock @ 3200 fps, would be good medicine indeed. I just can't see going to the trouble and expense of the 358 W, as a 358 STA is easier and cheaper, and the 358 W will need fireforming.

Paul, Bwana, correct me if I'm wrong, but I am under the impression that the STA must be fireformed, a step I am trying to eliminate. Yes, I realize the STA/Wby are essentially the same case. Can I just neck up brass for the STA and not fireform? If so, which caliber/make brass? Thanks

Well, yeah, unless you get them from A-Square or Quality Cartridge, you're going to have to fireform. I guess if you're absolutely opposed to it (you'll need to do load development, and lots of getting to know the rifle, so popping off a hundred cheap pistol bullets is really no biggie, even fun) then I have to ask why not a 358-8mm Rem or the like. You may find dies for that already as well. It was the original STA, actually, and Simpson felt it could do better in "improved" form, so he took some of the taper out. I think I'd have a hard time knowing I passed up a proven chambering (is it still a wildcat with factory brass, and a M70 custom chambering available?) for less capacity and the ability to neck and go.
Also something to think about, price out 340 brass and then 375 H&H. You can get it from everyone everywhere. Neck it down in one pass, seat a pistol bullet, "POP" and voila.
Anyway, I know first-hand how difficult it is to be talked out of something once your mind gets going on it. I gotta say, though, the STA will do what you want with a little less pressure than the 358-340. It's not a standard round, so it'll be something special to enjoy, that likely no one around you has, even if you didn't think of it yourself.
[edit:]
I just drew up a 358-8mm Rem, and as surprised to find it has over 99g water, opposed to the 101.something of the STA. There's not enough difference between the two to make any ballistic difference. But they are both longer than the Wby, just FYI. I say check around for a 358-8mm reamer/die set. Might be just the ticket.

if ya' want to spend some cash on brass how about necking down the 2.5" 375 dakota?
just curious if neck turning would be a chore shortening the RUM brass to 2.5"?
woofer

The Wetherby will have to be fireformed, so you won't gain anything by going that route.

If you're looking for a no fireform route, I'd start with one of the RUM cases, and neck it up or down. I'd probably go with the 375 RUM and neck it down, doesn't get any easier than that, and you have a plenty big case.

Thanks for all the input everyone. In the end I've decided to order a montana rifleman 1999 action, have it bedded into one of D'Arcy Echols excellent fiberglass stocks, top the whole thing off with a Leupold LPS 2.5x10 in Talley rings. Caliber? .340 Weatherby Mag. Opinions?

If you get a 34, make sure you check the magazine length of the Montanna because if it is only the standard 3.6" of the M70 or the 3.65" of the Rem 700 you will find that some 338 bullets seated to the cannelure will be too long.

That is the reason that the 338 Remngton Ultra is a 2.75" case length instead of the 2.85" of the 7mm, 300 and 375 Ultra.

Personally, I would prefer the 338 Ultra to the 340 Wby.

Mike

Since you will be looking for 3000 fps with a 250 gr .358 bullet, don't forget that you can also do this with a necked down 375 Dakota and keep an '06 length action.

I have read all the opinions here about the .358 Wby. I can attest only to the .358 STA because I have been shooting two for some years now. Quite simply, if you want to shoot a fast stepping .358 you can jump through and over many hurdles, or you can do it the easy way. Lilja make the STA chambered barrels that will fit any large enough action. You will not have to fireform brass, Bell makes STA stamped brass, or 8mm mag brass necked up will be easily prepared. I buy the new brass and fireform just to get another 1-2 grains of powder in the case to max the load, but that is not necessary. You can get 3200 fps with 225 grain, 3100 with 250 grain, 2950 fps with 270 or 280 grain with no problems. Pick your poison, but in my opinion the STA is the way to go. Good loading and shooting.

Phurley, 375 Wby factory load is 270g/2840, and I'm thinking they load to something like 64-65k psi, right? You're basically losing the freebore, necking down to .358" and running up another 10fps. That's GOT to be considered absolute max! And you're doing that with the 280g as well?
Do what you like, bro, but to everyone else, take it (like everything) with a grain of salt. There's no need to run the kinds of pressures this must be generating, especially with bigger cases available. Not that a 270 going 2850, say, would act any different to speak of (A-Square's max load).
nyrifleman, sounds like you had a change of heart. Too bad; I was looking forward to you getting talked into a 358-378!!
Happy shooting everyone!
(That's "Happy Shooting," everyone! NOT "Happy," shooting everyone....)

Out of the 358 STA with 3 different barrels at 26 inchs and 1 and 14 we got a bit over 3000 with 250 grain Hornadies. That was on Oehler 35.

Mike

Mike,
Who in Oz put together those rifles?
Cheers...
Con

Denis Tobler

Bwana-be ----- I shoot two STA's. One is a custom Model 70 from the Winchester custom shop. The other is a custom Model 70 built by a rifle builder from Wyoming for his son. He used a Lilja stainless barrel and post 64 action. The Lilja rifle will shoot every bullet 50 to 150 fps faster than will the Winchester barrel. I cannot figure why, except possibly the chamber size on the Lilja barrel is a smidgeon smaller that the Winchester chamber. I cannot fire a round through the Winchester barrel, resize and then chamber in the Lilja barrel. I can fire through the Lilja barrel, resize and fire easily through the Winchester barrel. From what I have seen written about the STA, my Winchester barrel is normal with others speeds, but the Lilja is faster than that norm. I chronograph 99% of my shots with an Oehler 35P, therefore I feel my speeds are realistic. When I state I can get speeds, I have actually gotten those speeds many times and average many groups to determine the speeds. Maybe I should say I get the above listed speeds, others should try your rifle and determine what are their best speeds. Once again, in my opinion from Alaska to Africa the .358 STA is an awesome chambering. Good shooting.

phurley

I have observed at different times that velocities obtainable from stainless match grade barrels have been higher than obtainable from factory barrels of equal lenghth.

Mike

Bwana-after going through all that I rechecked the ballistic tables and the .340 Weatherby is right there. It comes down to which side of the "what kills" argument you fall on- SD or the larger diameter bullet? I have a soft spot for the .35s but ballistically a .338 250 gr will out penetrate a .35 250 gr. The BC is higher as well. The rifle I have in mind will be a long(er) range elk rifle so the 340 makes more sense to me.

Well, FINE. Go play with your little 338!
(Kidding.) I have a soft spot for ythe 35 cal as well, but so much fo the gun-buying decision is eaither decidedly nonsensical or based on theory. In theory, I'll admit a 250g 338 will have better SD than the 358, but you could drive the 35 faster, "in theory" which might make it a wash. You will get a bigger (not better) bullet selection with the 338, and it will certainly do the job you ask of it, so you won't be sad.
I'm with Phurley regarding the STA. For a factory-ish round, it is among the stompingest.
Also, the 35 cal makes alot of sense when you consider you'll need a 257 Roberts, 300 Win, 416 Rigby, 458 Win and 50 Alaskan. See what I mean? Throw the 340 Wby in there, and the whole thing comes crashing down!
But hey, it's your life.

Lol. Now you've got me thinking about the natural order of my battery. Seriously Cabelas has a Win 70 Super Express listed on their website in 358 STA if anyone is interested. $2800, synthetic, stainless 24 in bbl, etc....

Just get yourself a Wby Synthetic in 338/378 and kill a few birds with one rock

Did I mention a few boxes of case and ammo will cost more than the rifle

Mike

nyrifleman ----- I shoot several large rifles along with the STA's. For years I have shot a .340 Wby, taking it to Alaska for Moose and many times to Colorado for Elk. It is indeed a very fine round and I have no gripes whatsoever with it, a tack driver with 240 grain North Forks. I also shoot a .338 Lapua, also a tack driver with the same bullet as well as Barnes X, XLC and Triple shocks. I have taken Elk and my 14 year old grandson (at the time) took his first Elk with it in 2003. ----- I just had always been facinated with the .358 calibers and when the opportunity presented itself on the first STA, I couldn't help myself. Now after five years of shooting them, I can only say good things about the chambering. You can shoot bullets from 185 grains up to 300 grains. My favorites are the North Forks but I have shot, Barnes X, Nosler Partition, Swift A-Frame, Kodiak, Sierra Gameking, Hornady, and probably some I am not listing. The North Fork 270 grain bullet has served me all over North America and Africa. In my opinion it is the best all around bullet I have ever shot. What my two STA's do with that bullet puts the .375 H&H to shame. As you can see I like to shoot big bullets fast, particularly when I am in dangerous game country. Just my .02 worth. Good shooting.