Barnes No.3 300gr load data for the .458 Lott (26" barrel). Got mine loaded at about start load speeds with the 300gr TSX and Sierra 300gr HP in deference to the muzzle speed limit recommended by Sierra.

https://www.americanhunter.org...win-mag-vs-458-lott/

https://www.americanrifleman.o...siness-the-458-lott/

Heavy hitting .458 Lott Norma ammo loaded with Woodleigh 550gr RN SN bullets.

https://www.norma.cc/en/Produc...a-Soft-Point-550-gr/

p.100


DoubleTap does .458 Lott ammo loaded with 350gr TSX.

2875 fps muzzle speed.

http://www.doubletapammo.net/i...3_356&product_id=485

4sixteen,

Thanks for ringing THE MISSION bell, even if it was done with the .458 Lott hyperbole.
As previously discussed, the only advantage of the .458 Lott is with light, short bullets that cannot be loaded long enough in a .458 WIN to surpass the Lott.

But If I can do +2700 fps with a 350-grain TSX in the .458 WIN (Bob has done +2750 fps MV in a 25" CZ), that is plenty fast.

The next area of superiority of the .458 WIN over the .458 Lott is going to come with a high-BC bullet for 1000-yard target shooting.
The 500-grain TSX of 1.65" length is capable of superb accuracy from the 1:14" twist.
The .458 WIN CZ can work it through the magazine at 3.780" COL, and get it going over 2300 fps ...
making perfect use of the fifth cannelure for crimping at that COL.

Imagine a pointy ballistic-tipped .458/???-grain bullet to load to 3.8" COL and use in a magazine-repeater CZ or the Ruger No.1 .458 WIN.
Imagine an AA Harlow scaled down from .510/700-grainer?
I'm on it.

That is a nice synthetic stock on the Ruger RSM .458 Lott:



Must be a custom fitting with internal stock rebuild, or have I missed something?

The .458 Lott pictured above is from this article, linked by 4sixteen:



Head to Head: .458 Win. Mag. vs. .458 Lott
by Philip Massaro - Friday, September 14, 2018

Once upon a time, the firm of John Rigby & Co. developed a 3 ¼″ cartridge, designed to launch a 480-grain bullet of .458″ diameter to a muzzle velocity of 2150 fps, and the hunting community was happy.
(That 480-grainer at 2150 fps muzzle velocity was from a 28-inch set of barrels on a double rifle.
Jeffery had created the revolutionary .400 S. Jeffery (S. is for Smokeless) in a Farquharson single-barrel rifle, and that was the first of the later-named class of Nitro Express cartridges (aka 450/400 NE 3" was first). Rigby gets the trophy for first DOUBLE RIFLE of Nitro Express class, second place on the order of cartridge fielding, with the 450 S. Rigby (S. is for Special), later known as the 450 x 3-1/4 inch Nitro Express.)

The .450 Nitro Express was deemed to be the perfect cartridge for the dangerous game of Africa and India. Then, during the desolation of British ammunition, supplies of .450 NE ammunition withered, and many fine double rifles were left to starve. The hunting community was saddened.
(Author makes his living at custom loading ammunition for non-handloaders. He thinks his analogy of starving double rifles is cute, because he feeds himself with ammo.)

The American firm of Winchester came to the rescue, filling the void left by the increasing absence of the .450 Nitro Express, by modifying the most-excellent .375 Holland & Holland Belted Magnum and mating it with the .458”-diameter bullets of the .450 NE. The .458 Winchester Magnum, released to the sporting public in 1956, offered the ballistic formula of the .450 NE in a bolt-action, affordable rifle. The .458 Winchester Magnum is a straight-walled case, using the H&H belt of brass for proper headspacing. Driving a 510-grain bullet at the same muzzle velocity of 2150 fps,
(Not exactly correct. Initial advertised velocity of ammo was 2125 fps for both 500-gr FMJ and 510-gr SP, in 1957 listings. It was 2130 fps a few years later.)
the .458 Winchester Magnum was a success—at least in theory.
(No, more than just in-smart-ass-hindsight-theory, it was a great success in actuality, in the field, first time to Africa in 1956.
First game killed was a rhino. First elephant shot with it took one brain shot and dropped dead, with the factory FMJ in Kenya in 1956, a big bull elephant.)

Winchester developed its ballistic data for the cartridge in a 26″ barrel,
(No, it was a 25" barrel like the rifle they first built in 1955, released to the public in 1956, and sold 1226 of the "Super Grade" M70 "Africans" by the end of 1963. All with 25" barrels.)
which is a bit long for a dangerous game bolt-action rifle, so the actual ‘street’ velocities never made the advertised 2150 fps.
(Rubbish! The H.P. White lab data of 1955-1956 showed it exceeded 2150 fps at very low pressures.)
Report of muzzle velocities as low as 1850 fps were not uncommon, and that makes a huge difference in performance on dangerous game.
(The ammo factory screwed up, or all of the squib-load BS is a Munitions-Industrial-Complex conspiracy to boost sales of other rifles and ammunition, since everyone was so happy with the .458 WIN that sales were stagnating. Not at all as much fun as when there were dozens of old cartridges and chamberings to grease the economy.)

Couple that with the fact that the Winchester case—shortened from the H&H 2.85″ length down to 2.50″ to work in a .30-06-length action—left little room for the powder charge, and there was a real problem with the cartridge. Field reports of squib loads from a result of the compressed powder coagulating in the African heat, caused more than a few dangerous situations; there were reports of bullets actually bouncing off an elephant’s hide—the problem was real.

In 1959, in Mozambique, a California hunter named Jacques P. Lott—known to his friends as Jack—had a terrible run in with a rogue Cape buffalo. He shot the beast with the then three-year-old .458 Winchester Magnum, and found himself airborne, bruised and bleeding as a result of being tossed by Black Death. He survived to tell the tale,
(Actually if you read the original story in the pulps, Jack hinted he screwed up, shot placement!)
but brooded on the fact that he needed to build a better mouse trap.
(The .450 Watts Magnum of circa 1949 was well known by then. But hey! If you shorten that one by 0.050" you can rename it after yourself, reasoned Jack.)
If the .450 Nitro Express rightly earned a reputation as an excellent choice for all-around big-game hunting, why did the .458 Winchester Magnum fail him? The bullets were dependable, so that left but one problem: the case capacity. Jack pondered the idea, and as the story goes, he drew the blueprints for what would become the .458 Lott on a napkin in a diner.
(Ha! The old diner napkin plot element!)
The concept? To boost the velocity of the (then) anemic .458 Winchester Magnum by lengthening the case to the full H&H 2.85″, allowing for greater powder capacity.
(That is the .450 Watts Magnum.)

Experiments were conducted with varying degrees of success. The first was to use a .375 H&H case, in a lengthened .458 chamber,
(I.E., it had an untouched .458 WIN throat, It was a .458 WIN at the belt and throat, just fitted longer brass in between those.)
loaded with a heeled .458″ bullet which tapered down to .375″. The resulting case opened up to the necessary .458″, but the fire-forming process shortened the case to 2.80″.
(Not quite, you need to trim it a little to square and uniform the case mouth down to 2.800".) That case-length would become the standard for the .458 Lott, which received SAAMI approval in 1989, after being produced by Col. Arthur Alphin’s A-Square firm. Not only did the new case solve the original issue, but offered a velocity increase to 2300 fps with 500-grain bullets.
(Author does not mention that the original .458 Lott with .458 WIN throat residual ("coned-up" H&H style) might get 2300 fps with 500-grainer, but not the SAAMI .458 Lott chamber which was done with a shortened parallel-sided-free-bore.
The MAP for the .458 Lott was increased to 62,500 psi, and it strained to do 2250 fps with 500-grainer at 3.600" COL.
The MAP for the .458 WIN remained a lower 60,000 psi, and it easily did 2200 fps with 500-grainer at 3.340" COL.
Same barrel length for both.)

The .458 Winchester Magnum plodded on,
(Plodded? He meant to say "sailed on.")
and the ship seems to be righted.
(See, a nautical analogy.)

Most modern factory loads still fall shy of the 2150 fps mark, but to be honest, so do many of the .450 Nitro Express cartridges.
(And so do some of the .458 Lott cartridges!)
I feel that anything between 2050 and 2100 fps is a fair shake for the .458 Winchester,
(Though it is capable of much more.) and a good bullet at those velocities will most certainly kill even the biggest beasts cleanly.
(Yay, verily.)
The .458 Lott has certainly earned its reputation as a wonderful big-game cartridge; despite the fact that a longer receiver is required, it is an excellent choice for any game that walks.
(That makes the .458 WIN even more "wonderful," for it can be used in a Lott-length receiver too (3.6"), as well as shorter than Lott-length (3.4") and longer than Lott-length (3.8").
In the 3.4" it is only 50 fps slower with 500-grainer than a .458 Lott. In the 3.6" and 3.8" it is faster at same pressure or same speed at lower pressure, or sometimes both faster AND lower pressure than the current SAAMI .458 Lott.)

So, which makes the better choice for a prospective big-game hunter? I feel that, hands down, the .458 Lott is a vastly superior cartridge when it comes to hunting animals that require a cartridge of this class. Firstly, it avoids the overly-compressed powder charges that come with the .458 Winchester; though it may seem silly, the 0.30″ increase in case length gives just the proper amount of case capacity to avoid powder issues. I’ve spent a considerable amount of time handloading for both, and trying to get the .458 Winchester to deliver muzzle velocities above 2050 or 2075 fps can be a real chore, especially in the shorter-barreled rifles. (And this guy handloads for a living?)

When handloading for the .458 Lott, I can easily obtain velocities in the 2200 to 2250 fps range—a bit below factory loads,
(OOH! Those magical factory loads!)
yet completely effective in the field. Secondly, the excellent monometal bullets, which are all longer than their lead-core counterparts, take up more space in the case, and will further compromise the already limited .458 Winchester case.
(It is all in the action length and the COL used, and of course, the throat. the .458 WIN or Jack Lott's original "coned-up" .458 Lott are better performers than the current SAAMI .458 Lott, with heavy bullets.)
The additional capacity of the Lott makes using these bullets, which give phenomenal penetration, much easier. Simply put, the Lott gives the shooter more options than does the .458 Win. Mag.
(Wrong. The .458 WIN, on balance, offers much greater versatility, see above.

I know a good number of Professional Hunters across Africa who’ve had their .458 Winchester rifles converted to .458 Lott;
(I have only one .458 Lott left to my name. I keep it for shooting the light varmint bullets fast, the only advantage it has over the .458 WIN.
I do use .458 WIN heavy-bullet loads in it, standard SAAMI, .458 WIN. The FN solids loaded to shorter COL feed better than Lott COL.)
one of the benefits of this maneuver is that .458 Winchester Magnum ammunition can safely—and rather accurately—be fired out of a .458 Lott chamber.
(With some loss of velocity of the .458 WIN ammo in the .458 Lott chamber.)
With hindsight, (There he goes with that hindsight thing again!) I firmly believe that Winchester would have (Does he mean "should have"?) used the 2.85″ case when developing the .458 Winchester Magnum; it’s just a smarter design across the board. It easily achieves that magical 5,000 ft.-lb. energy mark, has enough horsepower to give plenty of penetration—even on the huge pachyderms— (So does the .458 WIN, does all of that, easily.) and runs at relatively low pressures. (And the .458 WIN "runs" at lower pressures than the .458 Lott.) While the .450 NE made its bones with a 480-grain bullet, the Lott can easily handle the 500 and even 550-grain bullets, again giving the shooter more flexibility.
(Again, the heavier the bullet, the greater the advantage of the .458 WIN over the .458 Lott.)

Though it’s a relative newcomer on the scene, approaching its 30th anniversary on the market,
(Whippersnapper! The .458 WIN has been around for over 62 years, and is getting better all the time, with the new powders and bullets.)
it is one of the most sensible and economical choices for a big-game hunter who appreciates the benefits of a .458″-diameter bullet.
(The .458 WIN is even more sensible and economical and powerful with the benefits of a .458"-diameter bullet.)
Thank you Jack, for your design.
(Thank you James Watts for inspiring the .458 Winchester Magnum in 1955.)

Rip ...

quote:

Originally posted by 4sixteen:

quote:

Originally posted by sambarman338:
Thanks 4sixteen,
could you take out the bolt and look at the gas port up near the lugs? The model I reviewed had it pointing left in the closed position, which would have vented into the lug runway. I wonder if my gaffer may have passed on my complaint to Winchester/Sako, though, because I looked at another Hunter model a year later (about 1988?) and saw that the vent had been moved back to the r/h side, as it is on my 1979/'80 Finnbear.

Here's the bolt from my .458 Lott Sako AV (1991 production). With the bolt closed the hole between the 2 lugs lines up with the left hand side port in the receiver.

Presumably, in the event of a pierced primer, gas escaping against the bolt face into the firing pin hole would vent through that bolt side hole and out the receiver port.

So, they still had a hole venting to the left runway in 1991?

Even my old rifle has the vent in the receiver ring on the left but the bolt hole vents to the right as in that first pic you showed from the earlier model. That vented gas would all go from the bolt vent across to the receiver ring hole seems like wishful thinking to me, considering it has to cross a considerable void to get there. In the event of a blow-up or pierced primer there would also be gas exiting via the ejector slot etc, too, and any that went to the left side would be funnelling up the lug runway, possibly before the stuff leaking into the bolt got out. This might well divert bolt-vent gas to the rear as well.

I wish it had occurred to the genius who thought up that new hole to add a few grams of steel to the left side of the bolt shroud, just in case some of the gas did go up the lug runway towards the shooter's face.

Without blocking the gas a la Mauser 98, the gas would still exit - but at least the fatter bolt shroud might divert it a bit.

Has any firm ever thought of making after-market bolt shrouds for Sakos?

Thanks, RIP, for mentioning Jim Watts. He was a good friend of mine and I enjoyed writing his story. Lott took credit for what he did 22 years prior. When Jim went to Winchester with his round he could not understand why Winchester did not produce his cartridge. They said it was too powerful and chose the shorter option. Jim always thought they should have done what they did with the .458, .338, .300, and .264 BUT also should have produced longer versions of the same four cartridges to compete directly with Weatherby. Why Win. didn't do that will remain a mystery.
Again, thanks for mentioning Jim.
Cal

sambarman338,

Thanks for ringing THE MISSION bell,
even if it is about gas handling of the Sako.
I really am deficient in understanding of the Sako actions, none at hand.
What do you make of this, thanks to jwp475:

quote:

Originally posted by jwp475:
L61 sako actions will give you a face through the bolt. I’ve seen it happen.

Bolt through the face?
What is with the L61 actions?
If you had said Blaser whatever I would at least think I understood.

Now back to the Reverse-Seyfried-Schtick CZ 550 Magnum 2-piece "Picatinny."
I have done it, with the help of a GUNSMITH:
Low rings for the Nikon SlugHunter/InLine:



Actually that set up is 0.545" from action top flat to scope tube exterior.
The OEM CZ "Standard/Medium" ring height is 0.550" for the same measurement.
So, only 0.005" lower, but impossible without this setup due to short tube.
Other CZ extension rings may be available but they are higher than this.

Rip ...

I don't perceive pierced primers or case ruptures likely to happen so never worry about it.

Haven't tried to get more speed from my .458 WM but it's only a simple matter of seating the bullet out further as shown to gain more case capacity if the magazine and throat length can handle it. I use 300gr bullets in my .458 Lott for hunting anyhow.

I made this elongated .458 WM round as reduced loads in my .458 Lott using a compressed slow burn rate powder charge to keep the bullet from being driven into the case under recoil. Obviously no cannelure to crimp onto is problematic in heavy recoiling rifles unless it's a single shot.

Cal,

Welcome, and thanks for writing that book from your interviews of James Watts.
I have read it twice, once when I found it on a book rack in an Anchorage shop, last century, and again after about page 3 of this thread.
I refer to it whenever I get confused.
I feel a book review coming on, consisting of scans of the cover, front and back,
in hopes you will bring out a reprint.
Was that your first "gun book," in 1996?
Nice meeting you at DSC 2013, got your three big books, that makes 4, all signed by author.
Not a single underline or mark by me in any of them.
Thanks.

I actually had to "diamond-file" and "Dremel-polish" off a couple of corners on the front end of the Reverse-Seyfried-Schtick (RSR) front base.
This allows abut 0.040" clearance between the objective bell and each of the front corners.
It finally worked:

The GUNSMITH only had 3 Torx-head screws, used 1 slotted-head screw:

GUNSMITH said somebody has been using up his 8x40 screws.

Now I need to devise a recoil stop on the bottom of the front base:



No more holes to be drilled.
Solder, weld, or J-B Weld?

Rip ...

quote:

Originally posted by RIP:
The .458 Lott pictured above is from this article, linked by 4sixteen:



Head to Head: .458 Win. Mag. vs. .458 Lott
by Philip Massaro - Friday, September 14, 2018


Rip ...

Rip, Grand Master of the Order, Watcher of the King

This post alone deserves to go viral all over the internet for the sake of the new generations...it's just so full of wiseness that makes me to take a bow after you!

I can only say the Master himself is just too humble and generous to share this piece with us. Long live the Watcher!

Gustavo,

Thank you. Donkey.
Thank you very much. Buy a donkey.
Thank you very very much. Buy a buy a donkey.
That is Afrikaans lingo, in the spirit of the "African."

Rip ...

quote:

Originally posted by 4sixteen:
... Obviously no cannelure to crimp onto is problematic in heavy recoiling rifles unless it's a single shot.

True, but adding your own cannelure wherever you want, with a CH4D Canntool, and using the Lee Factory Crimp die might fix that problem,
especially if powder is selected to fill the case, as you say.

Rip ...

Front cover:

Back cover:

Book review: Great book.

Rip ...

quote:

Originally posted by RIP:
sambarman338,

Thanks for ringing THE MISSION bell,
even if it is about gas handling of the Sako.
I really am deficient in understanding of the Sako actions, none at hand.
What do you make of this, thanks to jwp475:

quote:

Originally posted by jwp475:
L61 sako actions will give you a face through the bolt. I’ve seen it happen.

Bolt through the face?
What is with the L61 actions?
If you had said Blaser whatever I would at least think I understood.

...

I'm surprised to hear that as the Finnbear is a massive action I'd been led to believe was pretty strong. If you'd said the little L461 Vixen, I might have been less surprised.

As to gas leakage, 4sixteen, I've not worried too much about it for myself as I always wear glasses and am a relatively cautious reloader. Whether there is a risk or not I don't know but, as with my optics hobby horse, it seems to me that engineering should not only be good but have the appearance of being good; and peering down an exposed lug runway is not a good look in my opinion.

DoubleTap also does .458 WM ammo with 350gr TSX at 2500 fps. A 375 fps shortfall compared to .458 Lott ammo. Their ammo would be compliant with industry standards.

According to the table below there appears to be a 25% pressure safety margin for CIP-compliant ammo (and probably for SAAMI-compliant ammo also).

Not a recommendation but conceivably that safety margin could be compromised - and beyond - to obtain higher and higher muzzle speeds. For either or any round.



https://bobp.cip-bobp.org/en/tdcc_public

(pressure in bars)

PE = 1.25 X Pmax = mean proof pressure (bar), which is the routine for any of the class CIP calls "Magnum cartridges," i.e., "belted cartridges."
Very gentlemanly of them. A baby-blue pill.

Remember CIP and SAAMI differ on the MAP's of the .458 WIN amd .458 Lott.

.458 Winchester Magnum:
SAAMI homologation of the .458 WIN specifies the same chamber as the original in 1956, same "coned-up" throat.
MAP or Pmax is set at 60,000 PSI, not the old 53,000 CUP or whatever it was originally.
Earliest CIP homologation of the .458 WIN is listed as June 14, 1984, revised May 15, 2002.
Pmax = 4300 bar = 62,350 PSI (if 1 bar = 14.5 psi). Close enough to call it 62,500 PSI.

.458 Lott:
SAAMI by 1995 (commercially loaded by A-Square as early as 1989, IIRC): Short throat by SAAMI spec. MAP or Pmax = 62,500 PSI
Earliest CIP date: August 24, 2000, revised May 15, 2002 --- It had the "coned-up" throat of the .458 WIN then.
2nd CIP Revision: May 16, 2006 --- Throat was changed to same short throat as SAAMI .458 Lott.
Pmax = 4300 bar, same as CIP Pmax for the .458 WIN.

So, currently SAAMI and CIP agree on the chamber specs for the .458 WIN and the .458 Lott.
SAAMI MAP or Pmax is lower for the .458 WIN (60,000 PSI) than the .458 Lott (62,500 PSI).

More evidence of the MIC Conspiracy!
Merely a plot to sell more guns and ammo.
Keep those .458 WIN ballistics down to make Bubba think he needs a .458 Lott.
Chuck Norris always preferred the .458 WIN, in any action he chose, at whatever COL he liked, and at same pressure as the throat-stunted .458 Lott.
If he needed an extra cannelure on the bullet and a good crimp, no problem.
He could do that with his fingernails and his teeth, however he chose.

Rip ...

With a 24" Lott chambered Wiseman barrel, Barnes #4 is showing 2349 fps/5513 ft-lbs from the 450gr TSX using 81 grs H335 @ 97% load density.

I've just loaded some 450gr X-Bullets (same bullet without the grooves) with 83 grs of H335 to a COL of 3.76". I'll shoot them from my #1 Ruger in .458 WM as soon as the weather permits (that might be next April!). That is still less that 100% load density. I'm expecting somewhere between 2350 and 2400 fps. If all goes well, I'll add a couple more grains of H335.

I'm no stranger to seating bullets long in any bolt actions I've owned from .22 Hornet (that was a single-shot) to .458 WM of which I've now owned three. Never a problem with bullet setback, but many flattened lead points in magazine rifles.

With multiple grooves, we have choices. If not, use a smaller neck expander ball by polishing it down in a drill press using fine grit to improve neck tension on bullets. And/or use a powder that loads to 100% density. In all my Marlins, I seated bullets "long" (2.61 - 2.62") and never had a problem in getting them to chamber or extract smoothly, or with bullets seating deeper under recoil of 50 ft-lbs using those methods. I also used a Lee crimp-die at times. For pure copper-lead bullets it will make a "crimp" where there is none without milling one.

In the New Year, I'll be ordering some 450gr TSX's. I also have part of a box of 450 A-Frames that I'll be giving a try in 2019 using H335 and A2230. Since I got over 2300 fps from my Ruger LT from those employing H335, I'll expect at least 2400 fps from the #1 Tropical -- while watching for good accuracy in the process.

4sixteen: Just for information's sake: I did get OVER 2800 fps (over 6000 ft-lbs) from my CZ550 shooting the 350 TSX but I never published it even though there were NIL expressions of offensive PSI. They were crimped into the bottom cannelure.

In the Barnes #3, it is showing a max MV for the 350gr XFB (one groove) of 2732 fps from 82 grs H4198. 85 grs of 3031 shows 2741. From that data I decided to go with 80 grs H4198 behind the 350 TSX in my 25" CZ550 (.458 WM).

I wonder what DoubleTap used, and how much @ what PSI?

Bob
www.bigbores.ca

RIP;

I want to thank you for all the work (tests, research, etc.) you've put into "the mission". Really, you've done a masterful job! I think you should write the book!

Thanks,

Bob
www.bigbores.ca

Bob,

Your plan sounds good.
I have all 4 of the Barnes manuals and refer to their .458 Lott data for my .458 WIN LongCOL loads, just like you do.

Double Tap is obviously part of the Munitions Industrial Complex conspiracy to hobble the .458 WIN.
Aside from being SAAMI compliant with their .458 WIN ammo shackling,
how would they sell any .458 Lott ammo if they did not keep their .458 WIN COL's short and their .458 WIN pressures under 60,000 psi?

Rip ...

http://www.barnesbullets.com/f.../2014/11/458Lott.pdf

"*Barnes 450- and 500-grain TSX bullets have the front cannelure positioned to maximize case
capacity in the .458 Win Mag. When loading these bullets in the .458 Lott we recommend
trimming the cases back to 2.760”, so that these bullets can be loaded within the SAAMI spec
COAL of 3.600”. If your magazine box will handle cartridges longer than 3.600”, this step is not
necessary."

In the CZ 550 Magnum .458 WIN we recommend loading the 500-grain TSX to 3.780" COL, crimping on the fifth/last cannelure.
With the CZ 550 Magnum .458 Lott, you have to seat the bullet deeper and use a shorter COL than 3.780".

Rip ...

CIP compulsory maximum pressure specifications are the same for the .458 Lott and .458 WM (62,366 psi). SAAMI voluntary maximum pressure specifications are 4% lower for the .458 WM compared to the .458 Lott. Maybe had something to do with ambient temperature-sensitive propellants that were widely used in factory loads at one time, and should be updated as CIP has done?

Likely nowadays .458 WM ammo is loaded to the same pressure level as .458 Lott ammo state-side as well.

p.34 https://saami.org/wp-content/u...4_ANSI-SAAMI_CFR.pdf

I can load my .458 WM Remington 798 with the 350gr TSX at about 2580 fps muzzle speed (23" barrel). Note that DoubleTap ammo is at 2500 fps muzzle speed from a 25" barrel and pressure is assumed to be held to the 62,000 psi industry standard maximum limit.

Based on handbook data my handload probably exceeds the 62,000 psi standard to use up a good portion of that 25% or so safety margin. Or maybe beyond.

Not recommended of course but no apparent excessive pressure signs neither.

quote:

Originally posted by 4sixteen:
CIP compulsory maximum pressure specifications are the same for the .458 Lott and .458 WM (62,366 psi).

4300 bar = 62,366 PSI, then 1 bar = 14.50372 PSI, which of course is 1 Atmosphere at standard conditions.
So, CIP has a lower Pmax for the .458 Lott. SAAMI MAP says 62,500 PSI = 4309.2392 bar.

SAAMI voluntary maximum pressure specifications are 4% lower for the .458 WM compared to the .458 Lott. Maybe had something to do with ambient temperature-sensitive propellants that were widely used in factory loads at one time, and should be updated as CIP has done?

Likely nowadays .458 WM ammo is loaded to the same pressure level as .458 Lott ammo state-side as well.

Please do cite some sources showing .458 WIN ammo loaded to same pressure level as the .458 Lott.
Voluntary, of course, not compulsory.

p.34 https://saami.org/wp-content/u...4_ANSI-SAAMI_CFR.pdf


I sure like paper, hate to be reliant on a 'puter for everything.
I have printed that entire 375-page reference out and bound it in an Oxford binder, 2015 date IIRC,
have added some newer pages since then, in sheet protectors as +375 pages.
Then handguns, shotshells, etc., in separate binders.
I have a 2005 bound copy of CIP, in a 3-ring binder (big one!) that I insert updates into (sheet protectors) whenever I find it useful.
Nowhere in the above do they address LongCOL loading of the .458 WIN.
Not even voluntarily!

If Bob and I could do the pressure testing of our loads with the .458 WIN LongCOL,
I am sure we could amaze the naysayers with some high velocities at pressures below the .458 Lott pressure level.
It is just so obvious and easy, I am not paying for the apparatus or lab fees.
The .458 WIN "coned-up" throat swallows the .458 Lott throat,
chews it up and spits it out.

Rip ...

quote:

Originally posted by 4sixteen:

Based on handbook data my handload probably exceeds the 62,000 psi standard to use up a good portion of that 25% or so safety margin. Or maybe beyond.

Not recommended of course but no apparent excessive pressure signs neither.

You mistake a proof load for a safety margin.
The SERVICE Maximum AVERAGE Pressure is what you do not want to exceed.
Whatever the Lott can do in that regard, so can the WIN: 62,500 PSI
If you load the .458 WIN Long enough, you will not exceed the .458 Lott Service MAP of 62,500 PSI.
Simple physics.

Rip ...

Silicone adhesive will replace the release agent (between Super Lug and receiver ring rear face) on final, removable, installation.

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Proof load implies a safety margin, load pressure is increased 1.25x. Upon firing the case and rifle withstand the higher pressure undamaged.

Much like process piping in industry is tested to 50% above maximum operating pressure to prove strength.

Nothing profound about increasing powder charge to get higher pressure to get higher muzzle speed.

Page 100 Ron

This must be the longest thread on a single calibre.

quote:

Originally posted by 4sixteen:
I can load my .458 WM Remington 798 with the 350gr TSX at about 2580 fps muzzle speed (23" barrel). Note that DoubleTap ammo is at 2500 fps muzzle speed from a 25" barrel and pressure is assumed to be held to the 62,000 psi industry standard maximum limit.

Based on handbook data my handload probably exceeds the 62,000 psi standard to use up a good portion of that 25% or so safety margin. Or maybe beyond.

Not recommended of course but no apparent excessive pressure signs neither.

Tumble the bullets in HBN slickems powder.
That will knock down some pressure.
Generally speaking, you don't want to beat book loads.

There was an Australia gun write who married an America and moved there many many years ago. He bought a 460 of me and he shoots those 350gr TSX and I think he also uses them in his 458.

There is a Weatherby forum based in Denmark and lot of pictures of animals hit with the 350 Barnes out of the 460s.

The 458 is all very practical. Like 7mm/08 and 308 the sort of calibre you get when entering the nursing home

quote:

Originally posted by Mike McGuire:
The 458 is all very practical. Like 7mm/08 and 308 the sort of calibre you get when entering the nursing home

Mike,

That is a very important consideration.
At the NRA Retirement Home for Incurable Riflecranks (NRARHIR) they have a rifle range for residents to use.
When shooting offhand, standing, with a 4-point walker and a pair of crutches for shooting sticks,
it is considered bad form to fall over backwards and break a hip or crack your noggin.
Likewise, when shooting from the sitting position in a wheelchair, a tip-over is bad form.
They won't let you unlock the wheelchair wheels before the shot.
Rolling backwards under impulse power is not allowed.
Too many nurses and orderlies have been run over.
Worker's Comp would shut down the NRARHIR if that was allowed.

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