If I understand correctly, a straight walled case will last longer then a case with a shoulder?

Perhaps this is due to the extra stress that occurs each time you full length resize, as well
the pressure exerted when firing?

Great point. Another plus for those old brits and their straight, or slightly tapered cartridges.

IIUC, Mr. Hubel you don't ever have to full length resize your brass, only trim it?
S

Mike-I didn't have to run the same pressure to
get the same velocity as the 460 with 500 gr..I am talking about peak pressure which is the biggest factor in case stretching..The pressure spike is lower,and gets to peak a little slower.
but the area under the pressure curve is larger.
And I had soft brass that wouldn't go much over 50k.When I used stick powders,
the brass only went 14-17 reloads.It is just
something that works out with ball.

Socrates-thats correct.And I full length resize,
but I set up the resize die to only be .004
smaller than the base size of the brass.That cuts down the reworking of the brass.And no shoulder to
work saves wear and tear.I have received 458 Win
resize dies that were .010 under base size.I honed
them out when I was reloading 458Win.Made that brass last a hundred times.I have seen other
resize dies for H&H cartridges the same way.To
much working the brass.I trim very little in that the chamber is .050 longer than brass size so
it has room to stretch and we are able to shoot more times between trims.Ed.

Are you saying that if I rechambered a 458 Lott to 450 Ackley I would be unable top get the same velocity. In addition loads that were maximum in the 458 Lott would beome excessive pressure in the 450 Ackley.

Mike

Mike- you should get a little more with Ackley as
it has about 10% more volumne to hold extra powder.Whether you will get 10% more I don't
know.Being the Ackley shoulder is not as big as the Weatherby, or in other words not as different in shape from the Lott, I don't know if a max load of fastest powder usable would go into an Ackley and work if Ackley was shorter to have same volumne.But the Ackley case has more volumne for expansion room so it should work...When I tried the 3 inch length in my wildcat
brass development process I got about same performance as Ackley, but not as good as Weatherby, so I went as long as brass let me.Ed.

Your showing 3200 in your cartridge for 400 grains and 3000 in the 460 and with both cases being the same capacity. How you get 3000 from the 460 with 400s I don't know but would like to know the load.

But assuming you are getting 3000 from the 460 and 3200 from your calibre, that is a 6.5% increase in velocity. As a general rule you will get a percentage increase in velocity equal to 1/4 of the percentage increase in case capacity. So in this case the straight case is giving the same velocity as a bottleneck case with a capacity 25% greater than the straight case.

Thus a 458 Lott should be quicker than a 450 Ackley and approximately equal to the 460 G&G.

It should also mean that a 458 is as fast as a 450 Ackley or 460 G&A Short.

Mike

Oh well, I'll pass on the current squabble, Mike375 and hubel458.

Good choice for something to top the 460 Wby: 500 A-Square or any of the other copycat rounds that followed John Buhmiller's wildcat of the 378 Wby case necked up to .510", including my own .510 JAB. Just get a 500 A-2

Or, if you prefer suspenders instead of belts, go with the 470 Mbogo. Hopefully it will be a factory cartridge someday. It has class. Thanks again Dave Estergaard.

Mike-If the right powder can be found for Weatherby it should get about 3000 with long barrel.I have been taught that for each percent
of load increase you should get half percent of
velocity increase.So a Wea case with 120 gr and mine with 135 gr is about 12%, by half gives 6%
increase in velocity.And a 12% increase in
energy as energy follows load size in a direct
relationship.You can't get decent velocities from
Wea, Lott, Ackley, Win. or mine with the short barrel nuts on the loose with their hacksaws.Ed .

I remembered reading an article on the Buhmiller big bores, so I dug it out of the bookshelf. The 2000 Gun Digest printed Bob Bell's article Buhmiller's Big Boomers, based on a collection of John Buhmiller's letters -- "Uncle John" died in '75. The writings covered the shooting of some 235 "big critters" that JB took hunting on his own mostly in Tanzania.

He used the .375 H&H and.458 Win Mag, and wildcats he made up on the cylindrical Norma H&H brass (.416, .458, .470, .510), and on the .378 Weatherby (again .416,.458, .470, .510). He also made some of the bullets, including cup-point solids.

jim dodd

Ed,
How much would you charge to rebarrel a Ruger #1 and chamber to your cartridge using a Douglas barrel,30 inches in length?I'm kind of intregded (sp?).

Out of a 13 pound rifle,with a KDF brake,recoil shouldn't be much more than a regular old 458 Winchester.

Brian.

Ed,

No it is 1/4. That will result in about a 1/2 increase in energy.

I seem to remember you saying earlier that you case was 3 grains bigger than the 460 case. As i remember your case was 3.45" long. That is .95" longer than the .458. If we assume an average of .463 inner diameter in thatb extra .95" of case then that section would hold 40 grains of water. So your case should hold 40 grains more water than the .458 Winchester. I am assuming that your case has the same head/base diameter as the 458 Win

Mike

[ 03-23-2003, 05:03: Message edited by: Mike375 ]

Brian-That is what we like hear is folks interested.I am not a FFL gunsmith, I just do my own.Don't like the bureaucrap.But there are many
on here,the best in the world.They will help you.
Any reading this please give a general idea of costs.Whichever gunsmith gets reamer first,
after brass is done may get a few to do.
As soon as run of brass is done and load tested
to make sure the chambers are right,I have reamer
manufacturer all set to make them.Same for dies.
If you weight gun and use 30 inch barrel,which
is length I recommend,with good pad you won't need brake. If you want to have brake with that
barrel and weight it will be like a 338.I am
going to post this on my thread about making run of brass also.Ed.

Mike- You can't have it both ways,It is a half
a percent gain in velocity for each percent of
powder added.In your own words in discussing the
Lott, when I stated the Lott had 90% of Wea
velocity you said tha energy was 80%,Thats correct.If Lott holds about 95 gr and Wea holds
about 118gr thats a quarter more and that is the
energy difference between the two also.Lott 6000 ft lbs--Wea 7500 ft lbs.And a velocity difference between the two of half of
one quarter or one eighth.Lott 2350-Wea 2650.
My case is bigger on the base so the it will
have more gain than that.More than 50 gr.Ed.

Ed,

I am not having it both ways. Increase case capacity by say 24% and you get 6% increase in velocity. Increase in energy will be about 12% or half the percentage increase in powder. For examplpe if we increase 3000 f/s by 6% to 3180 then energy is increased by 3180/3000 and the resyult squared.

My understanding of your reference to the Lott being 90% of the 460 was in terms of the velocity. So energy would be 2700/3000 with result squared which is 81%.

The extra .3" case lenght over the 458 for the Lott would add about 12 grains of powder. Witha 500 grain Hornady dropped into a fired case it will about reach the cannelure when a 458 has around 70 grains of 4064 or 4350 in it. A Lott would be about 82 grains. A 460 is around 115 grains. That isa bout a 40% increase in capacity so velocity increase shoud be around 10%. I think most would agree that 2300 is about the number for the Lott and 2550 for the 460. That would be a 10.8% increase in velocity and 22.9% increase in energy.

It is starting to sound like you are working on energy increases from calculations for your calibre and forgetting that energy increases as the square of the velocity.

Mike

Ed,
Uh,you could do the work for me for free,and I could be paying you for say,watching paint dry.

I really think a muzzle break (or brake,however you want to spell it)is an essential item on anything with a substantial (over 416 Remington level)recoil that will be used to engage long range targets (both paper and four legged)from improvised field positions.

A Barnes X 350,400 or 450 grain X bullet at those speeds would shoot REALLY flat.Combined with an accurate rifle of suitable weight with a KDF brake and a Leupold scope with target turret,you could lob them WAY out there.Heck,with a Leupold M8 4x with target turret and 500s at 2000 FPS,you can get to 500 yards.Crank that up 900 FPS and you should get to 800 at least,even more so with a lighter weight,spitzer bullet of good BC.

What do you think brass is going to run for?If it's the same or less than Weatherby 460s,I am seriously interested in building one on a Ruger #1,as is a friend of mine from Mississippi.

Brian.

Brian-Brass is 3 bucks each. That pays for tooling
punchs at Horneber plant, the manufacturing,the
shipping from EU, and import duties.Am working to get committment for 3000.Have 600 so far.I will
supply reamer to the smith you choose and he can
send it back or buy it to do more.Ed.

That's not too bad of price considering BELL 45 Basic is $2 a peice.

There's a 'smith in Oregon who works almost exclusively on single shots.I'll have to ask his opinion on it.Last I checked,his prices were far more than reasonable.

Brian.

Mike-In my 458Win I used 80 + gr of ball powder.The Lott will use 90 to 95 gr of ball powder.Weatherby will use about 118.Thse are loads
in books and mags.All ball to compare same density powder.Wea is 1/4 more ball powder.
So Lott is about 2350 fps and Weatherby is
2600 plus, about 1/8 more.This with long barrels
as ball needs long barrels.You mentioned in other thread you couldn't find improvement with ball over stick, but you also said you were using short barrels.Big bores don't get what is advertized with hacksaws on the loose.And as I
said earlier if right ball powder was around you could put 130 grains in Weatherby and get that
2700 figure.If I did a Col Jeff on my barrel
I WOULD NOT GET 2700, with 500 gr.Ed.

Ed,

You are using loads in that post rather case capacity. Keep it consistent. A 460 holds a lot more than 118 grains of Win 760

In 375 I have used 24 inch and 26 inch. But irrespective of barrel length my argument is about your wildcat getting so much extra velocity than the 460 "because the case is straight" but the 458 Win and 458 Lott failing to so when compared to bottle necks.

By the what is the head diameter of your case.....just in front of the belt.

Mike

I am consistant in that I compared actual loads of one powder, and proves that a percent of
added powder gives about half percent of velocity increase.And I said the weatherby can hold more ball powder, probably 130 grains.But with ww-760
130 grains in Wea is too fast, but full loads of
same in my cartridge is perfect,THUS MY CARTRIDGE IS IS BETTER TO LOAD FOR.That is why I think straight case is better, and it has no neck to work when resizing.The Lott can't quite match Weatherby, because Wea has much more capacity, where mine has same capacity.But Lott gets good results for its size.In this instance straight
case(mine) works with powders available for
max results and Weatherby doesn't. My case is
.527 ahead of belt.As I said all along straight case allows faster ball powder to be used than
in same size bottle neck cases, thus getting more velocity.Just a system that uses present circumstances to work;better powder for mine than is around for Wea.Ed.

Ed,

But I said percentage velocity increase is 1/4 of percentage increase in case capacity. If wish to compare two calibres with one calibre using an unsuitable powder....then good for you

When the 458 Lott is loaded with ball powder its velocity is right in line with what one would expect....as compared to the 460. In fact if what you said was right about ball powder then the 458 Lott would indicate that the parallel case drops velocity. Reason being that the 10% extra velocity the 460 affords over the 458 Lott is with the 460 using single base stick powder...IMR 4350...and the 10% increase is right in line with the increase in case capacity that the 460 has over the 458 Lott.

I agree that some calibre suffer from available powders being either too fast or too slow for them. However a 460 will develop ejector marks with a compressed load of IMR 4350.

Mike

Some calibers don't have right combinations--
But the straight cases do prove their slight superiority, in that they give 1/2 percent of
velocity increase for each percent of powder added.Here is proof,I loaded 458 Win with 81 gr
of 760,got around 2100 fps.Lott loads in book
are 95 gr of 760, giving about 2370 fps.My 458
with 135 gr of 760 gives 2800 fps.These are all compressed loads so they represent actual powder capacity, below 500 gr bullet.

Going from Win to my 458 is adding 54 gr more
powder, or 2/3 more over the 81 gr,AND VEL IS UP
ONE THIRD,2100 to 2800. That proves theory.

Going from Lott to my 458 is adding 40 gr about
40%, AND VEL IS UP ALMOST 20%. Proved again.

All straight cases.

If bottleneck cases only gain 1/4 to 1/3 of a
percent in VEL for each percent of increase......
........................

Ed,

You seem to be having roule coming to grips with the difference between case capacity and loads used.

In my last 460 I think 104 grains of 4064 did 2460 f/s with 500 Hornady and around 2400 plus with about 98 grains of an Australian powder that is about the equivalent of 3031. Hodgdon do not sell this powder. I say "around" and "about" because I can't remember the exact load.

So that is 3 grains more than your 458 Lott load and slighly more velocity.

Based on the increases you claim for your calibre as compared to the 460, then a 458 Lott should outperform a 460 G&A or 458 RUM. Think about it for a moment. You say your calibre has the same case capactity as the 460 and does an extra 200 f/s. In fact the 458 Lott should be about 100 f/s faster than the 460 G&A or 458 RUM on that basis.

Mike

My case only does 200 fps more than 460, because
I have right powder and expansion ratio.If
Wea had right powder and same expansion ratio,
it would only be about 30 fps behind mine.

Think of what I just said--"expansion ratio".
If I did a Col Jeff on my barrel, cutting to
21 inches I would make 2630 with ball powders.

The Lott will be about the same as the G&A and
RUM with right powder and expansion ratio,
considering they have about 15% more capacity,
if they have a bad expansion ratio.Which adding
powder capacity does if you don't add barrel length.If you have right barrel on Lott and
chopped off barrel on the others, yes it might get
a 100 more.But not because others are bad neccessarily, they like Wea are different
and in most uses are set up with bad expansion ratios.

There is formula for calculating velocities, that
incorporates expansion ratio and pressure used.
And that formula shows that velocity gain is
a half percent for each percent of powder gain.
And another formula comparing gains for
increasing powder capacity uses the half percent gain per one percent of powder added,
MINUS losses for the difference charge is
larger in dia compared to bullet dia.So it is possible that with powder charge a lot larger in diameter than bore that gains will only be a quarter as you mentioned before.

Brian who asked about putting my cartridge in
a Ruger #1, said he was using what barrel???
Think expansion ratio, and you have my cartridge.

Mike375,
You are making sense to me. Your rules of thumb regarding case capacity increase and bore size increase are good guides to the expected ballistic results, IMHO. This assumes sane working pressures and no over compacted loads or slight of hand, or excessively long barrels with one and not the other, etc.

I think Ed has a great toy here, but of what practical use?

Isn't the 450 NE No.2 3-1/2" long and with a greater case capacity than the .458 HE? It is loaded to low pressures in a rimmed case more suitable for doubles or single shots, if hunting is the purpose.

If a big-banger-bench-toy is the game, then why not go with something like a 500 A-Square, or a 50 BMG, or a .585 Nyati or a 577 Tyrannosaur?

I imagine that if Ed is getting the velocities he claims then he must have some very high pressures, and I don't see how he can reload the brass "forever."

I do understand that the purpose of the toy is to please the owner. That is fine. I have my own self indulgance in the .510 JAB, and I am quite happy to have the only rifle so engraved in existance.

The 3" .458 Express whatever would be more interesting to me as it can work through a reasonable bolt action repeater for both hunting and big-banger-bench-toy purposes.

Just my 2 cents, chinked into the pot, not a real stir, just a ripple in the soup.

PS: I just couldn't bite my tongue any longer!

[ 03-24-2003, 00:58: Message edited by: DaggaRon ]

My case only does 200 fps more than 460, because I have right powder and expansion ratio.If
Wea had right powder and same expansion ratio,
it would only be about 30 fps behind mine.

You said your case is the same capacity as the 460. Since your case is longer that will mean with equal barrel lenghths the 460 has higher expansion ration than your calibre.

I assume the basis for your claim that your calibre is 200 f/s faster than the 460 is not based on your calibre being chronographed out of a longer barrel. But then again since you say your calibre has a better expansion ration this could only be the case if you are using a much longer barrel since the capaciity of your calibre is the same as the 460.

As to powder, I have already pointed out that a 460 with 500 grain bullets will show ejector marks with a compressed load of IMR 4350. Compressed loads of Reloader 19 will also develop maximum pressure.

If Win 760 powder is the key to success then the 30/06 should be at 300 Win velocities with bullets in the 150 grain area. The 22/250 should be as fast or faster than the 220 Swift or 22/243.

Mike

DaggaRon

I certainly have no argument against "toys". How could I as a former spotlight shooter of roos with not one 460 but two 460s

But I still prefer the idea of toys and duscussion of toys not to result in a suspension of physics

Mike

Ron-No I am not getting high pressures,My brass is soft, not weak, but soft.Ross who I got most
of my cases from couldn't make them work for his wildcat experiments at all.I don't have an outlandish barrel ala Ole John, but 30 in, longer
than what most guys have on big bores.And as for practical use it will be perfect in #1s.And the 450 NE is a great cartridge I built this from, and it gave me idea of what to do,450 NE is great for single shot, but to hotrod it a little like I do mine won't work as 4 of the 5 cases
I checked in cartridge development were too thin
in the base for more than the old load levels.
The one I found is .240 thick like modern cases,
so it can go up.And non of the 540 #2 NE that I checked 6 years ago had thick enough bases or
my wildcat would be bigger.That is why we are getting run of brass made mainly for #1s, to load up with no danger of
blown out bases, and if committment is large enough we will do some with rim.And my case can reload 500 gr loads about 14- 17 times now,
and 350 gr loads a 100 times.If I work harden
brass with lighter loads then I can get more
reloads with 500 gr than 14- 17.Hornebers brass will be better.Ed.

Good points again, Mike. I am no physicist, but I do like to think that I too am in touch with reality. Let us at least play fair with the 460 Wby if comparing it to something else.

I do see the beauty of the vertical stack 460 Wby pushfeed. The custom shop at Weatherby is offering a drop box that extends this to more than two down now. Three down, I think, in a vertical stack and just replace the current floorplate and box on the Mark V with your screwdrivers. Fool proof feeding.

Alas, I have changed my mind, back to the CZ 550 Magnum, however. Love those CZ's. They grow on you.

Ed,
Have at it. I just don't get it. I would rather put a stainless McGowen barrel onto a CZ 550 to build a 460 Wby. Maybe a Mark V with one in the chamber and a vertical stack of three down would be interesting too. Just one of those gunnut things, to each his own.

Ron,

I think there is no doubt that the CZ in 416 Rigby is the best and easiest way into a big banger. Although the Mark V Synthetics in 30/378 and 338/378 are reasonably cheap but at minimum need a rebarrel if a "big bore big case" is desired as opposed to just a big case.

I had to suspend a few of my plans due to neck problems. Richard Corbin was king enough to put bullet making gear in 416 on hold for me. However, with some diet changes and and some other changes my neck is starting to feel quite good. Having a test run at the range next weekend. By the way the doctor said to me that my neck was like a rifle with some throat erosion, crappy bedding, crappy scope and shit ammo. He said I can fix the scope, bedding and ammo problems and then for practical purposes the rifle will shoot OK but it should be shot all of the time with a hot barrel

Mike

Mike-I have 30 in barrel, not 22 in barrel the
hacksaw nuts have operated on.And expansion ratio
is the ratio of powder chamber volumne below bullet,plus barrel volumne to the chamber volumne.
So if Weatherby has same volumne as mine then to have same exp-ratio it has to have same barrel length. Powder chamber size is what matters, when
figuring exp-ratio.If my barrel was 22 inch like
all the rest I couldn't keep up with them,with some of the stick powders out there as my chamber
don't work at optimum with those powders.And the stick powders that I would have to use on short barrels to get same velocity would be the type that gets to higher peak pressure faster and my brass life would be down a long ways.Which is not what I designed the thing to do.

The powder chamber dia in relation to the bore diameter also determines the amount of percent of gain in capacity is able to increase velocity.
On the magnitude of the diameter difference cubed,
times the half percent gain in vel formula.
So it is possible that one percent gain in capacity will only give 1/4 percent vel gain, if
powder charge is much larger dia than bore.

And as for whether other small caibers work good with ball powder, what is done on 458 is not a good comparison.And I never said anything like that...Ed.

Ron as I said before, I am single shot nut, and am economical wanting brass to last forever,
in the least expensive rifle to get setup in.
That is a #1 with my reamer run into one with
458 chamber.All the guys around here that will be
setting up #1s will never get to Africa, will use
350 gr for deer and target shooting, will get brass for 3 bucks each or less if it gets going,
and reload and shoot forever.Brass costs for
3 cents per firing...8 lb jugs of surplus powder.
350 gr bullets.A tremendous amount of economical shooting.Ed.

Mike,
I am just getting over a pain in my shoulder, minor rotator cuff strain, suffered from, of all things, the butt of a .375 RUM with Remington factory loads. Nothing else has ever hurt me. The rifle was the 23" barreled CZ that would do close to 2800 fps with the factory 300 grain Swifts.

I think pressures were high in the tight custom chambering. The stock is a straight back classic walnut, the pad a Decelerator.

I think I just held the gun wrong in some careless offhand shooting and it bit me just right, one shot did it, offhand. However, this does make me feel that excessive pressure loads kick harder, whatever the formula recoil numbers say. I will handload this rifle.

The factory rifle with 26" barrel shooting the same ammo just over 2800 fps seemed to kick less even though it weighed about 1.5 lbs. less. My physics escapes me again!

Well, mate, keep a stiff upper lip, and don't use too much gun. I know my limitations too.

Ron-Found your description of recoil from short to longer barrel matches what I have said about
my cartridge,IE you big have powder charge barrel
length is needed.Felt recoil is related to the
exceleration of bullet and powder, and the pressure of gases at muzzle.Jet effect.So long
barrel may have 7000 psi at muzzle, short can be
15,000 psi gase pressure.Ed.

So if Weatherby has same volumne as mine then to have same exp-ratio it has to have same barrel length. Powder chamber size is what matters, when
figuring exp-ratio

Not so. If case capacity of 460 and your calibre are the same, then the 460 will have the greatest expansion ratio in barrels of equal length. Reason is simple, your calibre for a given barrel length has less barrel in front of the case than does the 460.

In general terms you appear to be promoting your calibre on increased velocity over the 460 but with the same case capacity as the 460 and achieving your results by using a 30 inch barrel on your calibre Vs 22 inch barrel on the 460.

Mike

[ 03-24-2003, 03:22: Message edited by: Mike375 ]

Mike-I just said mine was better than neighbor's
Weatherby, That is way it is set up.Why would anyone want to burn powder loads bigger than
what 458 Win holds in 21-22 inch barrels.No matter what brand.And especially
I don't like short barrels for asthetic reasons, and recoil reasons.Seem screwball to burn big
charge-- cut off barrel-- hang on a muzzle brake,
gun as long as it was before cut off-----while
losing velocity and going deaf.

The Weatherby we compared to had 24 inch barrel.We only compared because fella said no homebuilt long sraight cartridge could beat his snob Weatherby, no matter what
we did.He believes the big shoulder gun mag
stuff.But that costs money if you shoot a lot, with cases going to hell in 5-10 rounds or less,
unless you load cart. to less than non magnum
velocities, that you bought magnum to make look bad.Competition you know.And even in same length
barrel I can still do as good or better, because
the 760 powder is just right, even with my soft brass.Ed

Ed,

I have no argument that your calibre in say a 30 inch barrel Ruger Number 1 is going to show very good results as compared to a 460 Wby in 22 or 24 inch barrel.

However, economics or rifle availability/cost is a separate issue to ballistics.

I disagree on case if full loads are used since that will be case life ending due to loose primer pockets.

If brass if full sized and if moderate loads are used and if there is a lengthy period of time** (maybe a month or more) between shots, then based on my experience with 458s I would agree case life will be longer with the straight case.

** Case life is always much longer if there is not much time between each shot. In fact if you go to the extreme of loading once case over an over at the range you will rarely see a case loss due to splits. But use the same loading and same sizing but fire the case one every 3 months and the results will be different.

While your cases are quite expensive that is OK since 460 cases are very expensive. If you are using single shot like Ruger then you can have the 460 capacity in a straight case and have extra case life if moderate loads are used.

But again that is all separate to the ballistics issue.

In my opinion your argument on ballistics being better for your case than the 460 is similar to someone arguing that the 35 Whelen generates better ballistics than the similar case capacity 350 Rem Mag. That is true bit it is because Rem 700s in 35 Whelen have 22 inch barrels and the Rem 600s in 350 Rem Mag has 18 inch barrels.

Mike

I went through the waiting between shots bit,
in over 40 years of reloading.And the full length
resizing with dies as they usually come was working my 458 Win brass over .010 so it was
.006 to .008 under specs after reloaded,I honed them out so that they only worked brass .003
and brass was right on when reloaded and the
problem you mentioned never showed up.There are ways to get around problems.I set my wildcat dies up the same way, and the ones made for any who do my case will be the same.With Horneber good brass
all will be told that for brass to last they can
not load so high that reasonable resizing does
not do the job.And 3 bucks isn't bad, because most will shoot lighter bullets and brass will last 100rounds,Thats 3 cents a shot.And if it takes off price may go down.Neighbor reloading had neck splits on his 460.As well as loose pockets.Never had neck splits on mine.Mine at loads that worked for soft brass just stretched
gradually and got thin just ahead of belt.

Now the 760 still gives me a slight edge as on the 24 in barrel, that we tested first,135 gr gave me 2600 fps.Usually Wea needs 26 in barrel to do that. Have you ever tried 760, and is your
460 a 26 inch barrel.The formula for figuring
velocity and velocity gains as percentage of powder in the chamber under bullet is increased
shows that any time the powder charge diameter is
larger than bullet diameter some effiency of
the percentage added is lost (thats the 1/4 gain
versus the 1 % added you mentioned),
due to shouldered vs straight case, with same
expansion ratio.Because some energy is used up getting past shoulder, stretching chamber and brass more, creating more heat,compared to straight case.IN comparing gains of my straight case 458 HE over the 458 Win
straight case the gain in powder was 2/3 and velocity was 1/3 for a half percent vel increase
per 1 percent powder increase, with same ex-ratio.. Ed.

Both 460s I owned had the Pendledekicker. The barrels were 26 inches including the Pendleton. As I remember the Pendleton commenced at about 23 inches or so wherin it opens into a big chamber. Thus my barrels would have been a real 23.5" to 24"

115 grain of IMR 4350 did right on 2500 f/s with 500 grain Hornadies. Pressure signs occured at just over 2600 f/s.

I had a locally made neck sizing straight line tool for the 460 and case life with 115 grains of 4350 was just this side of forever.

I also used 115 grains of 760 and results were about the same except that accuracy was a bit more conisyent with 4350 and blast was less with 4350.

By the way, your argument on the straight case been better for velocity should mean that the 270 WSM should be way down on velocity a it has a very large sharp shoulder. Also, the 458 Winchester gives less velocity that is predicted from 338 Win and 338/375 velocities. This allowing for the 458 case being slightly smaller than the either the 338 Win or 338 necked up to 375.

Also 450 Ackley is faster than the Lott. Given the very small difference in case capacity between the Lott and Ackley should mean that if no shoulder promotes extra velocity then the Lott should be as fast or faster then the Ackley.

You have mentioned before that the Ackley has a small shoulder. However if size of the shoulder was an issue then the various WSMs, the 6mm/06, 25/06, 270 and 30/06 would show up differently in relation to each other.

In the real world cartridges with large shoulders such as 6mm/06 compared to 30/06 or 35 Whelen tend to develop more energy for their bore size than is predicted. However, there are two reasons for this occuring. Firstly in accurate rifles calibres with large case cpacities for the bore size tend to hold accuracy levels to higher pressure. Secondly, as you neck a case up to bigger calibres you tend to lose a bit of net case capacity because of bullet length.

Mike

Mike375,
The load you had for the 460 Weatherby is the same I settled on as best. 115 grains of IMR4350 with 500 grainers.

IIRC, I was getting 2500 fps from my Mark V with the dekicker (Pendelton or Pilkington?) and from a McGowen barreled BBK-02, about the same, as this barrel was also 26" with a counterbored last two inches that was ported by gunsmith drilled holes, on the sides only, though some of those holes were drilled through the barrel band front sight band.

The BBK-02 is now rebarreled to 470 Mbogo, but that McGowen barrel will become a 460 Weatherby again. The barrel was custom turned to leave a 5" long full diameter shank, so there is room to whack off the threads and rethread for another action. Minus about an inch for the threads and minus 2 inches for the porting (if bobbed), I will still have 23" of barrel to burn that 115 grains of IMR4350. I like barrels of 23" to 25" best, on any rifle. This barrel would shoot 1/2 MOA with the "Mike375 Load."

Why don't we change the subject to what action is best for my next 460 weatherby?:

1. A vertical stack dropbox Mark V (1 up and 3 down)

2. A CZ 550 Magnum (1 up and 3 down)

Everybody ought to have a 460 Wby, the undisputed King of the .458's. Load it right and it will perform. Belt no good? Horse feathers!

So now we know what happened to Mike's neck: The Mike375 Load in the paddocks at full bounce? Or was it some other kind of crash test?

Just trying to see if we can stretch this thread out to ... Oblivion.