Gentlemen I have been kicking this around for sometime now! That is the ballistic advantages of both these calibers and their top velocities with a 225 grain premium bullet.

The .358STA has a Sectional Density of .250 using a Barnes X bullet.

The .338/300Ultra mag would have a Sectional Density of .281 when using the same weight 225 grain bullet.

It would seem right off that the advantage to penetration goes to the higher S.D. in the caliber, meaning the .338/300Ultra mag wins out in that department.

However, when it comes to the shocking ability of the two calibers, the .358STA stands alone in this catagory, according to folks like Layne Simpson and Col. Arthur Alphin.

The given velocities with both calibers are as follows:

Barnes reloading manual #3 has the .358STA with a 225 grain X bullet going a Max of 3128fps with a MAX load of IMR-4831 @ 87 grains of powder.

The .338Ultra mag is given a velocity of 2987fps using the same weight 225 grain X bullet, using 98 grains of "Big Boy" powder. The Case on the 300 Ultra, when neck sized up to the 338 caliber, should hold around 3 to 4 grains more powder, verses the plain .338 Ultra mag case. I don't know however if that will make any significant difference in actual velocity.

Nosler's reloading manual 5th edition has the .338Ultra mag with a 225 grain bullet going 3227fps with a Max load of 98 grains of RL- 25 powder.

Nosler has the .358STA with a 225 grain bullet leaving the barrel at 3081fps, using RL-19 powder at Max load of 89.5 grains.

My question to the board is which of these calibers do you think to be the fastest in velocity and do you believe that the "sectional density" difference between them is anything but numbers in actual penetration and killing of big game animals? Thank You!

I think you'll end up with 2 peas in a pod. Similiar velocity with bullets of similiar weight and construction, that will behave very much alike. The 338Ultra was shortened to fit the Rem magazine without bullets being seated too deeply, so if a Rem long action will be your choice of vehicle then my money would go to the 358STA. I thought about building a 358STA awhile back and its graces were it would fit the Rem magnum action and magazine, I could use formed 375H&H cases, and commonly available pistol projectiles for light practice loads. I'd still be inclined towards the 358STA with a 26" barrel or a 340Weatherby as a cheaper option yet. Either way your buying shares in the company which supplies your powder... :D
Cheers...
Con

Bits,

I have a .358 Norma. It can generate 3000 ft-lbs of energy with a 180 grain bullet, and 4200 ft-lbs with a 250 grain bullet. You've got a lot more 'horsepower' in the STA. If I were going to do a .358 STA, I'd use 300 grain bullets with it. Your sectional density goes to .334, and you have a rifle that can be used on a juvenile T-Rex. :D

Enjoy what ever you choose!

Lobo in West Virginia

Why even discuss a 388 Ultra mag when one can buy a .338/.378 Weatherby and get all the punch one needs? ;)

Why even discuss a 388 Ultra mag when one can buy a .338/.378 Weatherby and get all the punch one needs? ;)

..... on both ends :eek:

Zep, how's you're search for the perfect .338/378 elk bullet coming? I think if you line up 6 or 7 javelinas, it'll approximate a small elk (except for the horrible smell, LOL...)

If you guys are looking for a tough .338 bullet that holds together at high speeds, you may want to give the North Fork 240 grain a try.

I haven't shot anything with them yet, but they are pretty easy to load for, very little fouling, and from reports coming in from Africa, hold together as good or better than anything else when encountering heavy hide and bone with superb penetration at close range.
http://www.northforkbullets.com/338-240.htm

Gentlemen both these calibers will be in a Winchester model 70 action, perhaps I left that out sorry.

I am looking for a long range big game hitter! I plan on using it for elk, however I would like to take this rifle to Africa also next year. I just wanted the best of both worlds and am looking for the flatest trajectory also. I am somewhat mislead by what the reloading manuals say towards the velocity of both the .358-STA and the 338Ultra mag velocity wise. I figure with using the wildcat (300Ultra mag case and necking it up to 338 caliber, it might give me another 50 to 75 fps) it might put it a tad bit more ahead in the trajectory issue.

To put it bluntly if I can in FACT get 3200 fps with a 225 or 230 grain bullet with the .358STA, I would go with the bigger area on the bullet and NOT be so concerned about the lack of sectional density, as I know it will penetrate with those Barnes X bullets or Winchester Fail Safes.

I am just looking for more opinions in perhaps those who might have a .358STA or the 338 Ultra mag and compared them both in velocity with various weight bullets as well as penetration perhaps. Thanky you all for your replys!

PS MIKE........you crack me up with the little piggies!!!

Zepp! I don't want a Weatherby for 2 reasons OK. One is the muzzle brake that will be on the rifle and two, I am looking to have a "WILDCAT CALIBER".........Aim small on them piggies. LOL :D :D :D

2Bits,
I apologize if I'm stating the obvious, but what I would do is have a look at the bullets offered in both the .338" and .358" diameter. Look for the design operating velocities of those bullets. I don't know if there are more than one or two bullets made for the 358 that are designed to work at the velocity you intend to push them in the STA. I haven't looked, but would think even the most premium of the .358" bullets were designed around 358 Norma velocity. It might not matter as you state this rifle will be for long range, but the other side of the coin is having an animal at 10 yards away and the bullet coming apart on the shoulder or failing to penetrate.

There are quite a few .338" bullets that work in the 338-300 RUM velocity range, and I don't like having rifles that I only have one or two bullets from the start, that I can load.

I know I'm preaching to the choir, but if the bullet can't handle velocity, even the fastest of the velocity cannot overcome poor bullet performance, and you cannot ask a bullet to do something it wasn't designed to do.

Well I have to chime in here as I have a 358 STA and a 358/300 ULTRA. They are both built on Rem. 700 actions the 358 STA has a 24" barrel and does put a 225 GR. Nosler b/t across the screens at 3020 FPS and a 250 GR. Nosler Par. at 2900 and some change. The 358 /300 Ultra has a 27 .5 in barrel and put's 225 GRS. across the screen at a little over 3240 FPS. and the 250 GR. a solid 3100 FPS. and some change. I have shoot just about everything in bullets made for 358. cal. and the nosler 225 GR. whelen bullets shoot like a house of fire they kill them with no problems. If I where making the choice again as to build these 2 rifles again I would not give it a second though. Your concern as to not more than 2 bullets to chose from is not a problem there are at least 5 0r 6 different weights on the market to choose from and almost every major bullet maker makes 2 or more.Hope this helps with your choice.


hoeram

hoeram,
Thanks for that information. I wasn't sure about the bullet selection, and have run into that problem in past. Not having appropriate bullets is not a fun thing to scrounge for on a rifle you have built.

Thanks for the post!

I wish to express my gratitude to all those who shared their interests and gave information to help me narrow my selection down to which one to select for my intended interests. 2Bits!

Ok so don't keep it a secret which one have you selected to build everyone would like to know and I would to.

Hoeram :D

Ok so don't keep it a secret which one have you selected to build everyone would like to know and I would to.

Hoeram :D Thanks again for your information concerning those mentioned calibers!

I am leaning towards the .338/300Ultra magnum for obvious reasons. I feel the .338 caliber will be more accurate at long range shooting. I also know what the .338 bullets in various weights are like out their from the industry and their effects on various big game animals from mule deer to eland.

I do NOT want a barrel longer than 26 inches on this rifle and feel that those 3200fps velocities will be reached easier with the longer .338 bullet on top the 300 Ultra mag case. Any such worries about sectional density would be forgotten in this case. I have shot big game with a .375H&H and seen NO visual sign of a hit before, so I know the .358 isn't going to run leaps and bounds over the .338 bullet in that respect.

My mind is not however, 100% fully made up on this selection as of yet. I would like to get more than just a couple of opinions on the project before the money starts to leave my bank account savy.

2Bits

I understand your choice for the 338/300 in all it really comes down to what you really like best. They are both great rounds and will do well which ever you build.Enjoy and keep me posted on the project I would like to hear the parts you choose for this beast. By the way I have a friend who did the 338/300 Ultra and his shoots very well and he's real happy with it.

Hoeram :D

2Bits

I understand your choice for the 338/300 in all it really comes down to what you really like best. They are both great rounds and will do well which ever you build.Enjoy and keep me posted on the project I would like to hear the parts you choose for this beast. By the way I have a friend who did the 338/300 Ultra and his shoots very well and he's real happy with it.

Hoeram :D


The action will be a model 70 pre-64" Winchester which will be trued and polished rails and rampe for this long range big game getter! I will work up two bullet weights for the rifle. A 210 grain Nosler (hoping to get a solid 3250fps and a 275 grain Swift A Frame for the big stuff and velocity around 2900fps.

The barrel will be a Lilja in a 26 inch medium weight stainless. I am thinking real hard about a Hogue stock with aluminum bedding full length. A Decelorator pad on the rear of the stock. I want to keep it under 8.5 pounds. The barrel will be sent to Kelly at Mag-Na-Port for a porting job. This will be to help eliminate muzzle jump for the most part. The scope will be a Leupold 4 x 12 power.

2Bits

Hey it sounds like it will be a nice piece, send some pics of it when you finish it. Good luck with the project and keep use posted.

hoeram :D

Well I ahve to lean towards the 358STA because I have it's forerunner a 35 Ackley Improved Magnum that may have been built by Ackley himself (no way of knowing) it has a Buhmiller barrel and a stock made by Monty Kennedy. I still have not identified the action. I was going to have a fiberglass stock installed but the smith I hired couldn't figure it out either. He thought it was a magnum mauser action, anyway the darn thing shoots great but I have yet to go kill an Elk with it!!!!!!!!

Well I ahve to lean towards the 358STA because I have it's forerunner a 35 Ackley Improved Magnum that may have been built by Ackley himself (no way of knowing) it has a Buhmiller barrel and a stock made by Monty Kennedy. I still have not identified the action. I was going to have a fiberglass stock installed but the smith I hired couldn't figure it out either. He thought it was a magnum mauser action, anyway the darn thing shoots great but I have yet to go kill an Elk with it!!!!!!!!

How about letting us know what your loads were after being run through a Chrony OK.

I believe I can get more velocity out of the 338/300 Ultra mag, then the .358STA with the same weight bullets.