458 wm and cast

[charger 1]

So I know that bullets that fill the throat fly good. How the heck is that accomplished with the 458 wm funnel throat???? I was hoping to shoot ranchdog's group buy 460 425 gr. any thoughts?

[Larry Gibson]

Charger1

Funnel throat? I've not heard that one before, do you mean free-bore?

Larry Gibson

[charger 1]

Charger1

Funnel throat? I've not heard that one before, do you mean free-bore?

Larry Gibson

No I know what free bore is. In 458 wm's they hack the first 3/8" or so or rifling to a taper, because of how the 458 was originally(and poorly intended) to shoot some boolits as long as the case nearly

[Bass Ackward]

So I know that bullets that fill the throat fly good. How the heck is that accomplished with the 458 wm funnel throat???? I was hoping to shoot ranchdog's group buy 460 425 gr. any thoughts?


You should be able to "IF" your barrel can handle LLA. My suspecion is that you will need to stomp that bullet or hold it down around 1300 fps or less. If the Alox won't permit the HV, then you are on your own. I can't shoot LLA over 1400 fps in anything I own.

[charger 1]

You should be able to "IF" your barrel can handle LLA. My suspecion is that you will need to stomp that bullet or hold it down around 1300 fps or less. If the Alox won't permit the HV, then you are on your own. I can't shoot LLA over 1400 fps in anything I own.

Actually even though it has lots of small lube grooves,I was goin to try my favorite>lyman super moly. God I love that stuff

[waksupi]

I just ran a few rounds through my .458 WM. 6.5 gr. 4198, plus 60 gr. WC 872, behind the 560 Postell, gave me a group of 3.5 inches at a hundred yards. And, about as much recoil as I cared for!
Also tried 6.5 gr. 4198, with 77 gr. WC 872, behind the 405 gr. HP. The bullet was barely in the case. Accuracy was around thirty inches, or so. Don't believe I'll try that one again.

[Char-Gar]

Terms often get mixed up and/or change meaning with use over the years. In classic terms;

A barrel/chamber with freebore has the rifling removed in front of the chamber for a distance long enough for the bullet to clear the case neck before it contacts the rifling. I know it is popular these days, even among gunsmiths to refer to any throat as freebore. It is a waste of time, to try and tell these folks different.

To my memory the only true freebore was used by some Germans before WWII experimenting with hyper velocity rifles.

Some barrels have a "long throat", the rifling is absent in from of the chamber for a longer than normal distance. Most often his is done to accomidate a heavy bullet or a bullet seated out.

It used to be a common practice to long throat the 257 Roberts so the bullet could be seated out and leave room in the case of more powder. A Roberts so altered was often refered to as the 257 Maximum Roberts.

Weatherby used a long throat and called it freebore, but it really was not. It was supposed to reduce pressure, which it did, but it required more powder to give the same velocity as the same rifle with a standard throat. Mostly hype. Weatherby just loaded his round to gawd awful pressures and used lots and lots of powder in big cases.

Ruger uses a long throat in it's single shots and called it a "ball seat". Singles shots have no caming power on the bolt and even slightly longer seated bullets can cause rounds to fail to chamber.

Rifles for dangerous game often have long throats. With a pissed off Buff coming at your full tilt is not a time to find out your rounds are .006 to long to chamber easy. The concern is reliability and not accuracy.

What your are refering to as a throat funnel is just a form of long throating, so the 458 will be reliable under all conditions with all weights of bullets.

I would think seating and fitting of the bullet is the same as any other. Probably have to seat the bullets way out of maximum accuracy.

[felix]

Freebore should be labeled Freegroove instead. Anyway, freebore plus leade is equal to throat specifications. Freebore is always intended to be the same diameter as the groove dimension. Some BR guns are set up this way on purpose for the longer, full diameter boolits when case necks are short. A good solution for cast especially for the true alignment of a softer boolit. Downside is the growth of the freebore section in length, much quicker than if the throat had no freebore at all. Compare SAMMI specs for the 243 versus the 244, and you will see the latter's intentional freebore of some length. ... felix

[charger 1]

Terms often get mixed up and/or change meaning with use over the years. In classic terms;

A barrel/chamber with freebore has the rifling removed in front of the chamber for a distance long enough for the bullet to clear the case neck before it contacts the rifling. I know it is popular these days, even among gunsmiths to refer to any throat as freebore. It is a waste of time, to try and tell these folks different.

To my memory the only true freebore was used by some Germans before WWII experimenting with hyper velocity rifles.

Some barrels have a "long throat", the rifling is absent in from of the chamber for a longer than normal distance. Most often his is done to accomidate a heavy bullet or a bullet seated out.

It used to be a common practice to long throat the 257 Roberts so the bullet could be seated out and leave room in the case of more powder. A Roberts so altered was often refered to as the 257 Maximum Roberts.

Weatherby used a long throat and called it freebore, but it really was not. It was supposed to reduce pressure, which it did, but it required more powder to give the same velocity as the same rifle with a standard throat. Mostly hype. Weatherby just loaded his round to gawd awful pressures and used lots and lots of powder in big cases.

Ruger uses a long throat in it's single shots and called it a "ball seat". Singles shots have no caming power on the bolt and even slightly longer seated bullets can cause rounds to fail to chamber.

Rifles for dangerous game often have long throats. With a pissed off Buff coming at your full tilt is not a time to find out your rounds are .006 to long to chamber easy. The concern is reliability and not accuracy.

What your are refering to as a throat funnel is just a form of long throating, so the 458 will be reliable under all conditions with all weights of bullets.

I would think seating and fitting of the bullet is the same as any other. Probably have to seat the bullets way out of maximum accuracy.



Take a peek up the chamber of a win mag with bolt out then up the chamber of any other 45 cal magnum. All others throated or not end normally. The wm ends with about 3/8" of tapered rifling

[Char-Gar]

Charger... I didn't say the Winchester didn't have a throat different from others. I just said it was a "form of long throating".

You can cut the end of the rifling square, with a small taper or with much taper. It all depends on the reamer you use. Felix will check this out, but this taper/bevel on the end of the rifling is the leade.

I have a rifle with a throat like you mentoned. It is an original Sharps Borchard with an Axel Peterson barrel in 38-55. The rifle was built in Denver in the 1880s. The taper or funnel of the rifling end was done to make breech seating of the bullet easier. It is a cast bullet shooting jessie. I would think your rifle's long thoat style would be more of a help than a hinderance to cast bullet shooting, but I am only guessing.

I don't have a variety of bolt action 45 rifles to look at, at hand, at this moment, but I don't doubt your word that Winchester's long throating is different from others. There is more than one way to skin a cat.

In your case, this cone throat enables some slip and slide in the seating depth of the bullet..again to give a safety margin for dangerous game use.

[felix]

Musta' been 30 years or more ago where I read where some mechanical engineering outfit, under contract from some Indy racing team, tried various valve seating configurations. The conclusion was that the more rounded forms (i.e., more angles) were mo'betta' for maintaining compression, provided the valve train could compensate for the wear from gas erosion. Therefore, there is nothing wrong with having more than one leade form except for the time of cutting the chamber correctly. It is more practical to have one long angle, and allowing the boolit to seat itself positively with as much contact with the leade as possible. This technique requires a truncated cone boolit configuration. ... felix

[floodgate]

Chargar:

I believe the proprietary Weatherby magnums were designed and loaded, and their rifles chambered, for a substantial amount of freebore - in the specific sense you stated. I know the .358 Norma Magnum (and, presumably, the .308 NM) was intended to have a substantial freebore; mine was originally chambered with a relatively short leade, and I had pressure problems with factory ammunition until we had the freebore opened out.

floodgate

[Char-Gar]

Floodgate.. In 1960 I was a kid of 18 and my pocket full of money earned working on a shrimp boat that summer for a crazy Cajun. I also learned to play Booray, that summer as well. Anyway, I had a local gunsmith build me a 300 Weatherby based on a series 400 FN Mauser action and a Douglas "Timken" steel barrel. The stock was georgous walnut from Fajen with a Kollmorgen 6X Bearcub scope in Buehler mounts. It was a classy rig for the day.

We choose a standard throat instead of the Weatherby "freebore". It was commonly held the Weatherby chamber/throat gave up some accuracy over the standard version.

I also ordered four boxes of factory Weatherby ammo for cases. Long story short the first round blew the primer out of the case, and we had to use a wood mallet to open the bolt and the headstamp was almost gone. Uhhh..could we call that high pressure?

We double checked the chamber and it was in spec. I have no idea what pressures that ammo generated, but it must have been a blue whislter. The same ammo shot in a "real Weatherby" didn't do what mine did.

In those days, Weatherby published data on their rounds so you could duplicate their factory stuff. I was using good old Duport IMR 4350 and had to drop the Weatherby data by four or five grains to make it work. Even then, things were pretty hot. How does 84/4350/125 Sierra sound? You should see what that does to a coyote!

Fast forward a few years and I was in San Antonio at a range and a fellow was there with an early portable chronography. I had the Weatherby, and some of my wimp loads. I can't find the actual numbers now, but my downloaded stuff produced the full factory velocity in my standard throat as the factory Weatherby did with factory ammo in their "freebore" rifles.

I have been scratching my head ever since. You freebore a rifle to reduce pressure, so you can use more powder. When you do you also loose velocity. Sorta like the dog chasing his tail.

I started shooting and handloading in the late 50's. Those were pretty giddy ways for Wildcating and high pressure loading. Freeboring was more of a thing in those day. I wonder how we all survived with all our eyes and fingers considering some of the really dumb things we did with rifles and gunpowder.

I don 't have all of the math and technical skills you guys have.. but my limited experience from behind a gun butt, tends to indicate the long throating/freebore stuff isn't all it is cracked up to be.

But hey, I am the guy with a "D" in HS Freshman math, two "Ds" in Geometry and it took three trys to earn a C- in Alegbra so I could graduate. I am not much of a technical guy and not equipped to argue the fine points of theory and higher math with folks. But I do love the smell of powder smoke have have "smelt" my full share.

[Char-Gar]

Musta' been 30 years or more ago where I read where some mechanical engineering outfit, under contract from some Indy racing team, tried various valve seating configurations. The conclusion was that the more rounded forms (i.e., more angles) were mo'betta' for maintaining compression, provided the valve train could compensate for the wear from gas erosion. Therefore, there is nothing wrong with having more than one leade form except for the time of cutting the chamber correctly. It is more practical to have one long angle, and allowing the boolit to seat itself positively with as much contact with the leade as possible. This technique requires a truncated cone boolit configuration. ... felix
Humm..Interesting.. I wonder if that was some of the thinking behind Roy Weatherby eyeballs when he designed his cases with a "double radius" shoulder. Mo betta to hold the pressure in the case whilst the slow powder burned. I don't think it worked any better than a standard shoulder, but I have always wondered where he came up with the notion.

[felix]

He started out using the Ackley design. I also wonder if he was asked to change the shape, or did so because he could slow the powder some, thereby getting more average energy, by making rounded angles. So having rounded corners on the same hard angle, he could have a unique trademark, and keep the max pressure identical to that of the same case volume while wearing a normal 30-06 neck. The sharper the neck angle, the faster the powder burns. ... felix

[swheeler]

During the 1940's, Ralph Waldo Miller, a Southern California gunsmith, tried blowing out(fireforming)300 H&H Magnum cases to give a straight body, greater powder capacity, and a curiously shaped shoulder called venturi. This was called the .300 Miller Freebore, because Miller invented it and used long throats on his chambers to cut down on pressure. The cartridge was taken over by an astute promoter named E. Baden Powell, who called it the .300PMVF, which stood for Powell-Miller-Venturi-Freebore. Powell and Miller developed a whole string of cartridges using the venturi shoulder, and marvelous things were claimed for them.
About the end of WWII , Roy E. Weatherby, an insurance salesman and rifle lover, got interested in the PMVF series of cartridges. Instead of using the CONCAVE PMVF radius, he used the CONVEX Weatherby radius, which is the trademark of his cartridges.
Taken from" Complete Reloading Guide" J&R Traister

Although I believe Roys first cartridge, the 220 Weath Rocket(1942?) was an improved 220 Swift with a sharp, 33 deg shoulder. Scot

[Bullshop]

Any of yall remember the Herters double 30degree sholder of the Herters ram mags? They used to claim higher velocity equal to Weatherby but in standerd length cases. I have the fourth edition 1976 Herters load manual and they realy ham it up on thier design. You would think that by now every rifle chamber would use the Herters ram mag double sholder.
Yea I know but its fun to read!
BIC/BS

[Larry Gibson]

No I know what free bore is. In 458 wm's they hack the first 3/8" or so or rifling to a taper, because of how the 458 was originally(and poorly intended) to shoot some boolits as long as the case nearly

If you cast the bullets hard (15+ BHN) then I don't think you'll have a problem with that type throat up through 1500-1600 fps. I recently purchased some commercial hard cast PB 45-70 bullets from Midway that weigh 413 gr. In my 450-400-70 Siamese Mauser (really a 45-70 that is throated very long fro 400 gr Barnes to be seated to Mag length). I got really good accuracy (2 MOA if I remember right) at 1547 fps with 43 gr of milsurp 4895. The 45 gr load went to 6+ MOA. Thus I think you should do alright with your .458.

Larry Gibson

[9.3X62AL]

My CZ-550 in 9.3 x 62 has about .300" of freebore that transitions into a pretty gentle leade. Freebore/throat diameter is almost .367", while groove is dead-on .366". Using the MM 270 grain cast critters, they do very good work from this somewhat "Weatherbied" pattern--the ogive blends into the leade, the throat is filled with full-caliber drive band shank, and the boolit base is even with the bottom of the case neck. In this instance, things worked out well--a boolit that takes up no powder space in the case--fits the throat--is of the proper overall loaded length--and matches the barrel's twist rate.

With NosPart 286 grainers, there is a pretty good run at the rifling with a full caliber of seating depth, which could conceivably allow for a little more coal to stoke the boiler. 2450 FPS provides sufficient backward impulse to confirm primer ignition for me, and at that velocity (56.0 x IMR 4320) the primers still have a nice edge radius. Groups at 100 yards run 1.25" to 1.5". What's not to like?