Bob,

Yep, I always rap the adjustment turrets with an empty case or a knuckle after any adjustments,
religiously, whenever I don't backslide and forget.
Never hurts to do so.
The good it does I take on faith.

Great bear load, Bob. Those ballistics would loosen every screw in a standard-throated Marlin 1895 .45-70 Govt., unsafe there,
though excellent .458 WIN(-)P level for a bolt action or Ruger No. 1 .458 WIN.
Barely warming up, but over 200 fps faster than ballistics Elmer Keith thought excellent for timber hunting elk and black bear.

I hope to get my 400-ish-grainer hardcasts doing over 1800 fps accurately, for gentlemanly timber-hunting loads.

I am thinking I need to slow my 543-gr FNGC hardcast down to </= 1500 fps for same.

I am caught up on your blog.
Appreciate the honesty of the discussion on the two wounded and lost bears, in 3 or 4 decades of bear hunting ?
Blank happens, even to the best.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

I have a quandry with using QuickLOAD for my .458 WIN(-)P loads with .461"-diameter PCP GC hardcast bullets in the .458 WIN.
Is the start pressure closer to 1160 psi (cast lead handgun bullet) or 3625 psi (jacketed rifle bullet) ?
Does any non-bearing portion of the shank reduce the start pressure proportionally ?

I am not even bothering to get a precise bore area for a .459"-grooved barrel,
instead just using the QuickLOAD default for ".458-caliber" .458 WIN barrel.

There is room for refinement,
but still the total absence of throat handling by QuickLOAD.

So, add a grain of salt for each grain of powder.
I'll just go at least 5% above and 5% below the 32,000 psi prediction for powder charge,
and use foam wad filler as needed.
Then try to manipulate QuickLOAD refinements toward low-pressure load realism.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

I agree that QL is only useful in the .458 to get into the ballpark, still it is good enough to get to first base.

Also, for the (-P) with anything in the 400 grain cast bullet range, 2/3 of a case full of Red Dot is ideal - around 20 grains will get you to 1500 - 1600 fps at under 40k pressure.

I really like Red Dot for reduced loads as it is so "fluffy" that it fills cases at low weights and never hang-fires. It's like the cotton-candy of powders in that regard.

As a side note, it is also my go-to powder in the tiny little .32 ACP. I won't get into details with that round, but let's just say that 85 grain XTPs out of a pocket Beretta Tomcat at almost 850 fps, or 950 out of a 4-inch Cheetah are possible...

And RIP - I will combine my pressure traces with QL predictions soon to come up with a way to make them play well together. So long as I can keep the cable plugged in long enough to capture a trace...

Got a chance to step out and trace some more loads. The rerouted cable combined with a heavy bag behind the rifle fixed the disconnection problem and let me gather some actual data this time out.

First up, a "458 Win+P Torpedo" load with the 528 grain Lehigh Match Solid over 77 grains of H335 at a 4.22 inch COAL.



This load filled the case and the velocities were very consistent - within 1 fps as measured by the radar. Note that trace 1 has a slight ignition delay followed by somewhat higher pressure peak - it's almost certain that this bullet was pushed out of the case before the charge fully ignited and then was harder to engrave as it didn't get enough of a running start into the rifling.

A lighter charge of 76 grains had noticeably higher variation - 33 fps ES and 16 fps SD. It also looks like ignition was a little more difficult.



Next up is a 480 grain Hornady DGS over 70 grains of IMR-4895 at standard Win Mag COAL. Also very good consistency, 7 fps SD and 13 fps spread. Pressure looks dead on. Extruded powders are easier to ignite than ball, and that is visible in the beginning of the traces. The slight delays are gone and pressure variations are reduced as a result of a cleaner start.

UPDATE: As 416Tanzan has pointed out, there are some secondary pressure spikes at the end of the burns on these loads. The only ones I would be concerned about are the 480 DGS with 70 grains of IMR-4895. The ones with H335 and the Lehighs aren't out of the ordinary and are on-par with factory ammunition.



Primers used were Federal 215M that I have had lying around for quite a while. I will test with some new production ones that I just got in on my next outing. I also have some Winchester WLRM primers to try out as well.

Speaking of primers, of course no flattening or cratering occurred with any round fired.

The Maz,

Edit:
I was typing below while you were posting above !
Will go back and study those tracings.


Hang in there with the Pressure Trace, for THE MISSION, buy a donkey.

Yes, pistol powders do indeed offer a wide range of possibilities, especially for jacketed bullets and reduced loads up to 40,000 psi or even higher.
But, I need to keep the pressure down to 32,000 psi neighborhood for cast bullet accuracy.

Higher start pressure and larger bore area are somewhat counteracting,
so it is still a mystery how to get QuickLOAD to model the .458 WIN throat.
Back to just picking "ballpark" powders and trying them in the gun.
Your pressure readings add greatly to the try.

Reduced loads:
Looks like AA-5744 with filler is still great,
under 60% fill with 543-grainer 3.340" COL (about 1500 fps MV),
over 60% fill with 407-grainer 3.260" COL (about 2000 fps MV).
That is aiming for pressures no more than 32,000 psi, for BHN 25 bullets.

AA-2495 without filler is still my pick for 32,000 psi cast bullet loads.

I have just recently "remembered" that internal ballistics is the most important limit on cast bullets,
keeping pressures below the yield of the alloy while it is in the barrel.
If you want soft-point-type expansion on impact, muzzle velocity is not so much an issue, especially way down range.
But if you want FN-solid-type non-expansion up close,
then is when velocity easily gets out of hand with cast bullets.

RIP - Indeed the pistol powders are great with the cast bullets. I do have a few rounds loaded with 405 grain cast over 13 grains of Red Dot that I made up back when trying to get a subsonic load. They ended up a hair over 1100 fps if I remember. I'll try to trace a few of those next time out.

Also, QL was way off modeling the torpedos. It predicted nearly 78k with that combo and measured was under 60k.

The Maz,

That is surely looking good for the .458 WIN(+)P as well as the SAAMI .458 Winchester Magnum.
Fits my guesstimations just fine.
Buy a donkey for supporting THE MISSION.
Your interpretation and analysis of the results is most excellent.
.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

The Maz,

A pressure trace on the 13 grains of Red Dot with 405-gr cast bullet would be most enlightening.
.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

quote:

Originally posted by The Maz:
... QL was way off modeling the torpedos. It predicted nearly 78k with that combo and measured was under 60k.

QuickLOAD allows no consideration for throat effects.
If you did load the torpedos to maximum possible COL in the short-throated .458 Lott,
pressures might have been a lott closer to 78,000 PSI.
Instead:

.458 WIN+P/LongCOL the pressure averaged for three shots:

55,790 PSI
528-grain Lehigh VLD bullet
2186 fps
1 fps extreme spread
77.0 grains of H335
F-215 primer
COL 4.22"

Hornady brass ?

BUY A DONKEY !

Above done with a SAAMI .458 Winchester Magnum Ruger No. 1-H "Tropical" rifle with COL being no issue,
unlike if it were a SAAMI .458 Lott.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

RIP,

The Lehighs were indeed in Hornady brass. The 480 and 500 Hornadys were in WW brass.

Also the Lehigh loads were measured with an Intellidropper that weighs each charge to under .1 grain variation, whereas the other older rounds were just dropped from a normal measure.

And at 5604 fpe these definitely get one's attention when unleashed downrange.

The Maz's work is wonderful validation of the old war horse. There is nothing better on the planet.
One planet, one rifle.

Alderella is excited about trying the 407-grain cast bullets with AA-2495, this week.
She got dressed up for the occasion coming up,
back in the HS Precision stock with masterful bedding by Rusty McGee.



She only worries that the leather slip-on LOP adjuster makes her butt look big.
I think her butt looks great, especially since the slip-on has an extra half-inch thickness of yoga mat rubber inside it.
Gives rifle a triple recoil pad of sorts.
The softer the cushion, the better the pushin' on the shoulder.

Here is some leather that makes a rifle ugly:



That is a Blaser R8 Success Leather.
That there is suitable for Lottites.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

quote:

Originally posted by RIP:

There is nothing better on the planet.
One planet, one rifle.

Holy shit !!!!!! Ron, the 375 H&H crowd will be calling for you to be banned

There will be no Cancel RIP movement!

I think RIP is just getting warmed up!

Bob
www.bigbores.ca

Yo, dudes!

The pressure data above are exhibiting secondary spike phenonmena.

https://www.shootingsoftware.com/barrel.htm

Now that I have developed a promising load with the Lehighs, it is time to give them a test for accuracy. Before I do that, it might be best to get the copper out of my rifling! She's around 100 rounds since the last cleaning, which is around my normal interval when shooting jacketed, copper, or brass bullets.

quote:

Originally posted by 416Tanzan:
Yo, dudes!

The pressure data above are exhibiting secondary spike phenonmena.

https://www.shootingsoftware.com/barrel.htm

416Tanzan

I noticed that as well, but am not terribly concerned yet about it, as the secondaries aren't that high with H335, and I am actually more concerned about the slower start of the curve.

I am actually surprised by the ones seen with the IMR-4895.

One nice thing about this testing is that we get to try well-known loads and find stuff like this that we would never, ever, see without it!

It may be interesting to shoot another series with different and/or newer production primers to see if the ignition delay can be reduced or eliminated. Weak primers can slow the effective burn rate of the charge, and as we see from the ones that slow-start, increase peak pressure by slowing the bullet's velocity right when it is being engraved into the rifling.

I also saw the same thing with some older Remington factory rounds loaded with 450 grain A-Frames at around 2167 fps. (I only captured one trace, as I was fighting an issue with the cable disconnecting under recoil).

416Tanzan,

Buy a donkey for that link: https://www.shootingsoftware.com/barrel.htm



The "Catch Up Theory"
We do not know if the above load suffered from an accelerated burn rate (problematic with some ball powders), but agree with ballistic engineers about the probable cause.

The area under the pressure curve directly relates to the energy imparted to the bullet. The rise to peak pressure engraves the bullet into the rifling and establishes its initial acceleration down the barrel. The highest rate of acceleration occurs just past the point of maximum pressure. As the bullet travels toward the muzzle, lower pressure coupled with bore friction allows the rate of acceleration (not speed) to fall.

If there is insufficient gas produced by the powder (burn rate too slow), pressure behind the bullet will drop excessively. Then, as the bullet's rate of acceleration falls due to bore friction, gases may "catch up" to the bullet before it exits the barrel and produce a secondary pressure event. In the above load we believe the heat generated from initial ignition coupled with a secondary pressure event increased the burn rate of residual ball powder to near detonation.

Note: Secondary pressures readings taken at the chamber are lower and of longer duration than the actual event due to compression of gasses behind the bullet and the time required for expansion and contraction of barrel steel. The above event may have spanned only .1 milliseconds of time but could have reached 150,000 PSI!

Ball powders do not create the phenomenon of secondary pressures but the resultant pressures can be more severe. Indeed, secondary pressures can even occur when using large extruded powder. When using ball powders it is simply more critical that a powder with the proper burn rate be used to avoid secondary pressures entirely.

In every instance when secondary pressures are detected they can be eliminated by using a faster power, heavier bullet or a bullet with more bore contact area. Normal "tweaking" of loads may change the peak of secondary pressures but will not eliminate the problem. Below is the list of factors we now know can cause secondary pressures.

1. Powder burn rate too slow for the bullet.
2. Bullet weight too light for the powder's burn rate.
3. Bullet bore contact area less than normal for the bullet weight
4. Barrel longer than normal
5. Bore severely worn or incorrectly lapped (loose/worn toward the muzzle)
6. Moly in bore or moly coated bullets that reduce bore friction

We are often asked when secondary pressures are too high. Obviously secondary pressures more than 25,000 or 30,000 PSI at the weakest part of a barrel represent a safety issue. On a more practical note, loads that exhibit secondary pressures often show significant variation in barrel timing (when the bullet exits at the muzzle). Even if the timing does not vary shot to shot, it certainly will when the temperature changes so these loads rarely shoot well. Our advice is simply to avoid all loads that produce secondary pressures and keep peak pressures where they are supposed to be, in the chamber. If you shoot factory ammo, try a different brand. If you reload, use a slightly faster powder or heavier bullet.

I am tasting no urine in my Cheerios right now.
.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

The Maz,

This is complicated, new to me.

Your secondary pressure waves are hardly horrendous,
but the point about trying a newer lot of your primer is interesting.
That will be a new one for me, never worried about aging primers losing their brissance.
Have you been using a tight crimp ?
That is also an aid to initiation.

I also wonder about the thermo ballistic independence of the Hodgdon Extreme extruded powders.
Would H4895 be any different than IMR-4895,
regarding the secondary wave ?

I predict 3 half-hour soaks with WIPE-OUT to get that much copper fouling out of your barrel.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

quote:

Originally posted by RIP:
416Tanzan,

Buy a donkey for that link: https://www.shootingsoftware.com/barrel.htm



The "Catch Up Theory"
We do not know if the above load suffered from an accelerated burn rate (problematic with some ball powders), but agree with ballistic engineers about the probable cause.

The area under the pressure curve directly relates to the energy imparted to the bullet. The rise to peak pressure engraves the bullet into the rifling and establishes its initial acceleration down the barrel. The highest rate of acceleration occurs just past the point of maximum pressure. As the bullet travels toward the muzzle, lower pressure coupled with bore friction allows the rate of acceleration (not speed) to fall.

If there is insufficient gas produced by the powder (burn rate too slow), pressure behind the bullet will drop excessively. Then, as the bullet's rate of acceleration falls due to bore friction, gases may "catch up" to the bullet before it exits the barrel and produce a secondary pressure event. In the above load we believe the heat generated from initial ignition coupled with a secondary pressure event increased the burn rate of residual ball powder to near detonation.

Note: Secondary pressures readings taken at the chamber are lower and of longer duration than the actual event due to compression of gasses behind the bullet and the time required for expansion and contraction of barrel steel. The above event may have spanned only .1 milliseconds of time but could have reached 150,000 PSI!

Ball powders do not create the phenomenon of secondary pressures but the resultant pressures can be more severe. Indeed, secondary pressures can even occur when using large extruded powder. When using ball powders it is simply more critical that a powder with the proper burn rate be used to avoid secondary pressures entirely.

In every instance when secondary pressures are detected they can be eliminated by using a faster power, heavier bullet or a bullet with more bore contact area. Normal "tweaking" of loads may change the peak of secondary pressures but will not eliminate the problem. Below is the list of factors we now know can cause secondary pressures.

1. Powder burn rate too slow for the bullet.
2. Bullet weight too light for the powder's burn rate.
3. Bullet bore contact area less than normal for the bullet weight
4. Barrel longer than normal
5. Bore severely worn or incorrectly lapped (loose/worn toward the muzzle)
6. Moly in bore or moly coated bullets that reduce bore friction

We are often asked when secondary pressures are too high. Obviously secondary pressures more than 25,000 or 30,000 PSI at the weakest part of a barrel represent a safety issue. On a more practical note, loads that exhibit secondary pressures often show significant variation in barrel timing (when the bullet exits at the muzzle). Even if the timing does not vary shot to shot, it certainly will when the temperature changes so these loads rarely shoot well. Our advice is simply to avoid all loads that produce secondary pressures and keep peak pressures where they are supposed to be, in the chamber. If you shoot factory ammo, try a different brand. If you reload, use a slightly faster powder or heavier bullet.

I am tasting no urine in my Cheerios right now.
.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

De nada, RIPo,

y cómpra GOYA

Extensive Pressure Trace work was done by Doc M at McCourry Institute of Ballistics near Conway, SC.
One of his loads for the SAAMI .458 Winchester Magnum caught my eye.
It was recorded on 11/27/2013 from the 24" barrel of a Winchester M70,
at his indoor range, presumed temperature ~ 70*F:

CEB 450-gr Safari Solid, brass FN
77.0 gr of AA-2230
F-215 primer
2-shot average of 2311 fps (2314, 2308, ES 6 fps)
Average pressure 59,453 PSI

Too bad that bullet with its funny bands cannot be loaded any longer than about 3.360" with 2.500" brass.
But Doc M's shortCOL .458 WIN load just about exactly duplicates the HEAD TRAUMA .458 Lott Load at 3.580" COL with the .458/ 450-gr Barnes Banded Solid.
The 3.340" SAAMI .458 WIN did it with 77.0 grains for 2311 fps.
The 3.580" SAAMI .458 Lott did it with 76.0 grains for 2310 fps.
I do believe the two different rifles had same 24" barrel length, 1:14" twist,
and velocities are instrumental at 5 yards,
until I am told otherwise.
Factory .458 WIN barrel.
Custom .458 Lott barrel.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

On another thread I quoted Ross Seyfried in a response to backup sharpsguy's comment on the handgun for elephant.
In RIFLE #204 (Nov-Dec 2002)
Ross Seyfried did a roll-out of the SAAMI .458 Lott. He said:

"... Selous killed many elephants and buffalo with his .461 Gibbs Metford rifle.
This used a 540- or 570-grain, slightly hardened, lead bullet with about 1250 fps velocity.
These would penetrate completely through most buffalo and to the far side of elephant.
The .475 revolver will exit both shoulders of a buffalo and has been known to make the frontal brain shots, penetrating into the neck, on big bull elephant.
This with 430-grain bullets and 1300 fps velocity."

And further along in extolling the virtues of the SAAMI .458 Lott, about Jack Lott, Seyfried said:

"He also knew that a more or less 500-grain bullet with 2,150 fps
(This is approximately the velocity of all the British medium-bore [.400 to .500] cartridges.)
was not only adequate but also stunningly effective against beasts large and small.
I can attest to that from my use of the British cordite rifles.
They pound buffalo mightily, and I myself have driven a 480-grain solid at 2,120 fps from my .450,
from the last rib on the left and through the collar bone on the right of a big bull elephant.
We do not need more!"

Then Seyfried reveals a severe lapse in understanding of SAAMI .458 chambers:

"Last but not least, was the ability of the .458 Lott to use factory .458 Winchester ammunition.
This is almost like .38 Specials in a .357 magnum.
The Lott chamber offers .300 inch freebore with the Winchester, which may actually lower the peak pressure.
The velocity is usually very close to what the same round does in a Winchester-length chamber.
So one can have his more powerful,
or even better, 2150 fps loads with low pressure and the ability to buy the most-common-big-bore-in-the-world shells to fit in the same rifle."

It is sad when one's hero is shown to have feet of clay.
Better to laugh than to cry.

Ross Seyfried did not realize that firing a .458 Winchester Magnum cartridge in a SAAMI .458 Lott chamber
subjects the cartridge to a shorter freebore than when it is fired in a SAAMI .458 Winchester Magnum.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

https://www.fieldandstream.com...ous-game-cartridges/

By David E. Petzal
July 10, 2020
David is a regular comedian at FIELD & STREAM, and he says:

3. The .458 Lott

Barnes Vor-TX Safari ammo in .458 Lott.

The .458 Winchester, which was supposed to be the ballistic equal of the .470 NE, was not.
Was too ! When properly loaded, the 1955-tested laboratory data showed over 2150 fps with 500-gr bullet at less than 53,000 CUP,
in a 25" barrel.
Factory .470 NE ammo usually does less than 2100 fps with 500-grainer in a 24" barrel.
In order to reduce the cartridge length, the Winchester engineers sacrificed powder capacity and instead of getting the 2,150 fps they wanted, the real-world muzzle velocity with a 500-grain bullet was often around 1,900 fps, which is a lot of horsepower to forfeit.
If true, that would have been in a 22" barrel with factory ammo sabotaged by the actions of someone with the mentality of a U.S. Dimwitcratic Party member.

Enter gun writer Jack Lott who, while hunting Cape buffalo with a .458 in Mozambique in 1959, received a stomping from a bull that was unimpressed with the Winchester round.
David forgot to mention that Jack's first shot was a gut shot and then all hell broke loose,
Wally Johnson emptied his .375 H&H and finally recovered Jack's tossed .458 WIN to finish off the many-times wounded cape buffalo.
Lott brooded on this for some time, and then began looking for a cartridge that would keep him out of the hospital.

Not finding what he wanted, he designed his own,
I.e., Jack rustled up James Watts' wildcat and changed its brand after shortening it by 0.050".
which was simply a .458 with a longer case and greater powder capacity that gave 200 to 300 fps more than the Winchester round and greatly increased its power.
Possible only when Jack rechambered a SAAMI .458 WIN.MAG. without setting the barrel back,
thus retaining all of the original .458 WIN throat length measured from breech face.

Introduced in 1970,
(the wildcat rustling occurred in 1971)
the .458 Lott propelled 500-grain bullets at an honest 2,300 fps.
(Only when it had an honest .458 WIN.MAG. throat if pressure was honestly less than 62,500 psi in the .458 Lott.)
It was, and is, a very effective cartridge—some say better than the .470 NE—and it is considerably cheaper than the heavy British rounds.
Those are all attributes of the SAAMI .458 Winchester Magnum at honest pressures less than 60,000 psi.
It has become popular with professional hunters as a stopping rifle for buffalo and elephant. (It’s too much gun for anything smaller.)
The .458 WIN was all of that too, long before the .458 Lott.
The Lott’s one handicap is its 70 foot-pounds of recoil. In 1992 I took a Lott to Zimbabwe and killed my best buffalo with it. The rifle bashed him absolutely flat, which does not happen very often, but it also caused the ring finger and little finger in my left hand to go numb.

When I got home I asked a doctor what I could do about this, and he said, “Sell the rifle.” So I did. The guy who bought it was just as impressed with the Lott as I was.

4. The .458 Winchester

Hornady Dangerous Game Series Superformance in .458 Winchester Magnum.

Despite its initial problems, the .458 quickly became hugely popular in Africa, due largely, I suspect, to the low cost of the Model 70 African rifle and the ammunition for it. The initial stigma of the underpowered ammo never really left the .458, however.
Obviously wrong. The stigma was not INITIAL or the .458 Winchester Magnum could not have developed such a following.
It came later with botched factory ammo. I blame the IQ of a Dimwitcrat.
I took one to Zambia, and slew a buffalo, and a hippo, and all manner of other game, and had no problems with it whatsoever, but the impression I have is that it’s lost a lot of its popularity to other cartridges.
And now it is on the rebound and it is the .458 Lott that is looking silly.

Notwithstanding, I know a number of professional hunters who have shot prodigious amounts of dangerous game with one, and will look at you strangely if you suggest that there might be something wrong with the .458.
That ".458" would be the .458 Winchester Magnum, for sure.
All others are pretenders.
.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

I consider the secondary spikes with H335 to be acceptable, especially now that it is that is about the only powder available.

just got off the phone with John at Hornaday yesterday and he told me the 458 Win Mag brass will go into production a little later this month. Yea Ha

quote:

Originally posted by The Maz:
First up, a "458 Win+P Torpedo" load with the 528 grain Lehigh Match Solid over 77 grains of H335 at a 4.22 inch COAL.



This load filled the case and the velocities were very consistent - within 1 fps as measured by the radar. Note that trace 1 has a slight ignition delay followed by somewhat higher pressure peak - it's almost certain that this bullet was pushed out of the case before the charge fully ignited and then was harder to engrave as it didn't get enough of a running start into the rifling.

A lighter charge of 76 grains had noticeably higher variation - 33 fps ES and 16 fps SD. It also looks like ignition was a little more difficult.

Comment above the second pressure trace said 76 grains H335 though the pressure trace itself is labeled with 74 grains of H335.
Typo on which one ?

Agree 77 grains H335 is a fantastic load.

I would also be tempted to see how much Hodgdon BENCHMARK (extruded powder) I could substitute for the H335 (spherical powder).
I would happily compress the BENCHMARK to about 2200 fps with the 528-gr Lehigh Torpedo.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

quote:

Originally posted by hydehunter:
just got off the phone with John at Hornaday yesterday and he told me the 458 Win Mag brass will go into production a little later this month. Yea Ha

Good news !
The resurgence in popularity of the .458 Winchester Magnum has increased demand for brass.
Old stock has been exhausted.
New production is coming.

.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

Another note on the pressure traces.

One shot (T3) in the first group had a THIRD pressure jump.
Did that result in a flyer? It wouldn't surprise me. Or was it just a data glitch?

Just thinking outloud and wondering if that isn't a reason why some powders "don't work" in some people's rifles or combos.

416Tanzan,

I don't think The Maz was shooting groups yet, just now learning how to get the apparatus to stay connected.
If there was only a 1 fps extreme spread on the 3 shots, I doubt he would have noticed any flyers yet.

You got me thinking too.

The slick brass bullet compared to regular jacketed has only about half the start pressure.
Reduce the bearing surface by 50% with grooves/bands and start pressure might be less than one-quarter of a usual start pressure,
and with a long non-bearing ogive reducing the bearing surface relative to that of a same weight jacketed bullet,
maybe way less than a quarter ?

That is like using moly coating on a too light bullet with a too slow powder.
Those are three known possible factors for a secondary pressure wave.
In this case all bound up in one slippery brass bullet that near instantaneously teleported itself down the barrel ahead of the burning powder and gas.

Now, please do not ask me to explain the 480-grain Hornady with IMR-4895.
I will have to blame some voodoo associated with IMR instead of H powders.


.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

THE MISSION is getting some of its material reworked on this thread:

http://forums.accuratereloadin...043/m/5341074452/p/7

This has inspired the idea of a heavy and slow FN solid buffalo/elephant penetrator or sleeker target nose,
and a fast and light "Express" bullet shooting to the same 100-yard POI with same sight settings.

Double-bullet Regulation in a single-barrel rifle.

George Gibbs did it very nicely as illustrated by the sights on Ross Seyfried's "Selous Rifle."
.461 Gibbs
570-gr/90-grBP~1250fps
and
360-gr/100-grBP~1600fps

Both bullets hit dead-on at 100 yards with same sight setting, fixed standing leaf.
Various folding leaves and ladder graduation for each bullet take over for longer ranges,
out to 500 yards for the light bullet,
800 yards for the heavy bullet.






.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

For THE MISSION:

Yep, Ross only got two things wrong in his professional gunwriter career.

1. He recommended that Hornady and Ruger should choose the .450/.400 Nitro Express Magnum 3.25" for factory production,
instead of the first-ever Nitro Express cartridge, the .400 S. Jeffery of 1897, later known as the .450/.400 Nitro Express 3".

2. He "denied" the .458 Winchester Magnum before the cock crowed three times.

Nevertheless, he is the Muhammad Ali of the latest four decades of gunwriters.

DOUBLE GUN & Single Shot JOURNAL is a great publication.
Here is the excerpt for review purposes from the Summer 2004 Edition.
It happens to contain some of Ross Seyfried's best work on pages 75-88,
which must be viewed in full context to be fully appreciated:
























.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

Onward to page 461, a new angle on the case length thing:

This is from an 1882 Gibbs catalog showing that the .461 Gibbs No. 1 was the LongCOL ancestor of the .458 WIN+P,
and the .461 Gibbs No. 2 was thought of as the better "Express" rifle,
better only with the light bullets, like the .458 Lott:
Similar conniption fits with brass and paper-patched bullets occurred in the various Sharps cartridges too,
during the decade before.





The British and Americans just kept leap-frogging each other until the final perfection of the concept in the .458 Winchester Magnum by the Americans.

.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

Two more replies and onward to page 209, so here is one borrowed from the 45-70 for elk and moose thread:

quote:

Originally posted by sharpsguy:
Seyfried has a way of making the old rifles come alive. More importantly, he convinces them to give up their secrets.

Yep, in most masterfully ways.

The 1995 G&A Jim Gosnell article did report this on Ross Seyfried:

"Ross Seyfried shot an Australian buffalo with a .475 Linebaugh.
He hit the animal in the rear hip with a cast 430-grain bullet traveling approximately 1,380 fps.
The bullet penetrated six feet into the buffalo and came to rest in the neck.
Along the way that bullet broke the rear hip and the front shoulder."

Seems to me that "right" and "left" would have been better than "rear" and "front" in describing the hip and shoulder locations relative to the body of the buffalo !

Anywho, Gosnell mentioned only this about the .458 Linebaugh in the 1995-published article:
"... a new caliber of his (John Linebaugh's) design based on the .45-70 case."
There is a tiny black&white image of an ornate pair of Linebaugh custom Ruger Bisleys captioned as .458 Linebaugh and .475 Linebaugh. That is all.

Another gem in the article was Gosnell's wet phone book testing of penetration depth:

.375 H&H Hornady 300-gr FMJ/solid at 2,550 fps: 40 inches
.500 Linebaugh 420-gr LBT/cast at 1,205 fps: 41 inches
.475 Linebaugh 420-gr LBT/cast at 1,378 fps: 47 inches

"Again, this was in fresh phone books."
(new batch for each shot, soaked overnight with water)
"Even though there was no expansion of the lead bullet, there was an impressive channel left in the wet phone books.
I repeated this test several times to verify the results."

And Jerry's "vaccination load" load with the BPCR .45-70, 492-gr FN/cast at about 1300 fps, might do even better than the .475 Linebaugh.
That means better than a .375 H&H.
The .45-70 BPCR lever action is a buffalo and elephant rifle !
****************************************************************************************************

Some .458 WIN(-)P loads with 543-grainer at 1300 fps and 407-grainer at 1800 fps might make a great combo,
hoping for double-bullet regulation to the sighting of a single barrel at 100 yards.

.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

quote:

Originally posted by RIP:

Comment above the second pressure trace said 76 grains H335 though the pressure trace itself is labeled with 74 grains of H335.
Typo on which one ?

Agree 77 grains H335 is a fantastic load.

I would also be tempted to see how much Hodgdon BENCHMARK (extruded powder) I could substitute for the H335 (spherical powder).
I would happily compress the BENCHMARK to about 2200 fps with the 528-gr Lehigh Torpedo.

.458 WINCHESTER MAGNUM PERFECTION

Non Illegitimi Carborundum

While entering the filename on the range, I was copy/pasting the name of the previous charge fired. The process of capturing data, arming the radar, and saving files and comments is a workflow where minor typos are easy to commit, but I did keep track of the data in other ways - mainly by watching the file timestamps and knowing which was shot when.

It looks like I will be staying mostly with H335 for the time being, as powder is hard as hens' teeth to find right now, and I have about 18 pounds of the stuff.

I finally got the rifling de-coppered. Let's just say I had to use multiple sessions with Sweets to get that out, but now the bore is looking pristine again.

A real accuracy test with the 77 grain H335 load is planned soon. My shoulder can take 10 rounds without recoil-reduction techniques that affect accuracy and impact point negatively in my opinion. More than that and groups go to hell in a handbasket as cumulative bruising starts to occur. I am also debating using a higher-power optic for that job instead of the 4x shotgun scope, though the risk of scope nose is kind of a turn-off.

quote:

Originally posted by RIP:
416Tanzan,

I don't think The Maz was shooting groups yet, just now learning how to get the apparatus to stay connected.
If there was only a 1 fps extreme spread on the 3 shots, I doubt he would have noticed any flyers yet.

You got me thinking too.

The slick brass bullet compared to regular jacketed has only about half the start pressure.
Reduce the bearing surface by 50% with grooves/bands and start pressure might be less than one-quarter of a usual start pressure,
and with a long non-bearing ogive reducing the bearing surface relative to that of a same weight jacketed bullet,
maybe way less than a quarter ?

That is like using moly coating on a too light bullet with a too slow powder.
Those are three known possible factors for a secondary pressure wave.
In this case all bound up in one slippery brass bullet that near instantaneously teleported itself down the barrel ahead of the burning powder and gas.

Now, please do not ask me to explain the 480-grain Hornady with IMR-4895.
I will have to blame some voodoo associated with IMR instead of H powders.


.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

I do buy in to the fact that the secondary spikes occur and are real, but don't really buy in to the pressure-wave theory. I chalk it up more to the way smokeless powder burns and heat transfer into the granules.

When smokeless powder burns, it actually first boils on the surface of the grain, which is called the "foam zone" and is about 10 micrometers thick. The foam slows heat transfer from going deeper for a few microseconds, with the rate of transfer dropping with the drop in pressure as the foam's microscopic bubbles actually can expand to a slightly larger size and conduct less heat.

The foam zone is surrounded by a thin fizz zone, where the powder's vaporized molecules decompose into smaller, very reactive species. That in turn is surrounded by a flame zone, where the heat is liberated, and some is transferred back to the granule.

In my personal theory, the pressure drops fast enough due to volume increasing a bit too rapidly that burning is momentarily overly slowed, but the heat is still penetrating the kernels and making new foam, which at a certain point fizzes at once, or at least very rapidly, and almost detonates.

It is actually, in my mind, similar to a slightly lean engine knocking where the flame front stalls but heat causes remote gas/air mixture to go off instantly instead of a steady burn.

And you got me to thinking Rip. I have often Observed that Barnes data often favors powders faster than other data does. Coincidence? Great thinking material indeed.

The Maz,

Are you a chemical engineer specializing in thermodynamics of propellant combustion ?
That is some mind expanding thoughts there for us duffers.
Keep at it, please.
Buy a donkey for supporting THE MISSION.

.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

Fury01,

I think the QuickLOADs for the FURY01 bullets will be found to overestimate both pressure and velocity in the long-throated .458 WIN,
if your powder lot is anything like my AA-2495 by the QuickLOAD accuracy of characterization.
In other words,
you might get velocities 100 fps slower and pressures 8000 psi lower than the QuickLOAD simulation.
Just my SWAG, safe for normal good practices at handloading.

A great day at the range was had by me yesterday.
I started low with the 407-gr Blue Bullet and 64.0 grains of AA-2495 (~90% fill) and topped out at 72.0 grains (~101% fill).

According to QuickLOAD, I was expecting 32,000 psi at midrange charge, with accuracy getting better as I approached that, then going south above that.
I was pleasantly surprised that accuracy just got steadily better with that BHN 25 bullet, all the way to maximum charge.
QuickLOAD suggested maximum pressure around 40,000 psi, but I think it was probably about 32,000 psi,
my goal for accuracy with BHN 25.
I happily settle for lower pressure with my cast bullet loads.

Maybe QuickLOAD is correct about the 101% fill,
and 100% propellant burn.
AA-2495 has proven itself to burn very well at relatively low pressure,
and it is just right for a full-case load, NO FILLER, with the Blue Bullet at 3.260" COL,
3-shot, one-hole group, with 1 fps extreme spread
for those 3 shots:
5-yard chrono: 2157, 2158, 2157 (estimated MV 2170 fps for BC = 0.300)
3-shot-one-hole at 50 yards: 0.73 MOA

.458 WINCHESTER MAGNUM PERFECTION
Non Illegitimi Carborundum

90% fill, for fouling and scope adjustment: