DaggaRon

Neck:

As far as neck problems go I reckon they were cause by both the 375 H&H and 300 Win mag and not by 378s, 458s and 460s.

The 378s and 460s etc simply limit the number of shots you fire. Whereas the 300 Win and 375 H&h let you rest rifle loosley and fire lots of shots. Although it is has become quite apparent that a substantial party of my neck problems were lifestyle based and which is why I have been a able to get a real good improvement.

460 Wby:

Ron, I have seen a few 460s chronographed with that load and around 2500 seems to be the number. I think Mitch gets the same velocity as well. I think Weatherbys are quite consistent from rifle to rifle in terms of load/velocity and I believe this is due to the very long freebore. In my opinion the very long freebore tends to cancel other chamber variations asuch as leade angle etc.

I have owned two 378s and chronographed two others and they were also very similar and like the 460 the 378 has huge freebore.

As to rifles for the 460, I think Weatherby calibres belong in Weatherby rifles. Personally I find the idea of a Weatherby calibre (especially those based on the 378 case)chambered in a CZ rifle to be as offensive as having a 375 H&H or 416 Rigby chambered on a Made in Japan Mark V Weatherby

Note: If ever I should come to own a rifle in 416 Rigby I can absolutely guarantee you that such a purhcase will not increasee the list of Weatherby rifles I have owned

Mike

Ackley is about 7% more capacity than Lott.
It doesn't have 7% more velocity at same pressure
levels.The formula I mention refers to figuring
gains, and applying is to WUSSAMS etc,comparing to each other has no bearing unless you take one and lenghthen it out.Like comparing a short
WUSSAMS to a long RUMMY and you will see the gain
is like the 1/4 factor you mention, just because
the shoulder design cuts efficiency, and the effiency of gain.You talked about 458--338--338/375. If you compare the energy
out of each one who is ahead. The 458 with no more powder than others,About the same or less.Why is that.Well there is no neck to work against,as the bigger bore matches charges diameter.And I was getting the 2600 from 24 in barrel, with soft brass.No sticking.I could get more but cases are soft.You were getting pressure signs you said, at 2600 , 23 inch effective barrel,with the best brass in the world.It is the shoulder that is the difference.I takes some energy to work against that.How fast will 500ASq
put a 500 gr bullet, where almost all shoulder is gone and powder charge diameter is close to bore size.About 2800 with 26 in barrel.A-Sq will get a
700 gr to 2400 fps.Next step; will 50 bmg with almost twice the powder shooting that 700 gr
bullet get twice the energy of
ASq, No only about 55 % more(about 1/4 more velocity),Why. well the shoulder takes up some of the energy you added.You don't have the effiency of the charge diameter , being the same as bullet diameter, in getting the increase.

Again I got the same in 458 HE straight case, with
soft brass(Probably 10,000 psi less than 460 runs), compared to 460 Wea with best brass.It is because of the straight case.Ed.

Ackley is about 7% more capacity than Lott.
It doesn't have 7% more velocity at same pressure
levels.

A 7% increase in case capacity will at best be a 1.75% increase in velocity. That comes out to be true as a 1.75% increase is about 40 to 50 f/s. Again, further proof that that percentage increase in case capacity if divided by 4 will be the potential increase in velocity.

"You talked about 458--338--338/375. If you compare the energy
out of each one who is ahead. The 458 with no more powder than others"

Ed,

Remember you were the person that mentioned "expansion ratio" a post or three and/or six ago.

Are you aware that if a 264 Winchester has a barrel long enough so that the volume of the barrel in front of the mouth of the case is the same as the volume of the barrel in front of the mouth of a 338 Winchester case with a 24 inch barrel, then ignoring friction, the kinetic enegy will be the same.

Work is done by gas expanding.

Let us say that we settle on a 26 inch barrel and we have two barrels that are .264 groove diameter.

One barrel is chambered for the 264 Winchester. The case is 2.5" long so the gas has 23.5" of barrel volume to expand.

The other barrel is chambered for a parallel case of the same capacity. Such as case might average .270" internal diameter. Say .280" plus a bit near the base and of course .264" at the neck end. Such a case will need to be about 3 times longer than the 264 Winchester case so as to have the same case capacity.

That will mean the case is 7.5" long. That is 5 inches longer than the 264 Winchester. That means there will be 5 inches less barrel volume.

So with a 26 inch barrel the 264 Winchester has 23.5" of barrel for gas to expand. The straight case with the same capacity as the 264 Winchester will have only 18.5" of barrel for the gas to expand.

23.5/18.5 = 1.27.....Thus the 264 Winchester has an expansion ratio that is 27% greater than a straight case with the same case capacity and when used in barrels of the same length.

Please Note: If the work is not done by the gas expanding....then.....Apollo 11 is a hoax

Mike

[ 03-24-2003, 13:17: Message edited by: Mike375 ]

The Ackley in all loadings I have seen is about
a 100 to 130 fps faster, about 5%,And actual loads are about 10% more powder.The 7% was case
increase, but subtracting bullet space, you can
most loadings show 10% more powder.

The example of 338-458 is my point,and you mention it,where ex-ratio is better when powdercharge matches diameter of bullet, so more
work on the bullet gets done.And less on the chamber.If I was developing a long skinny case
to push a bullet, with same volumne as short bottleneck case, you would add enough barrel to
make ex-ratio the same allowing for case being
longer,Thats what I did for mine.

You are right expanding gases must do work.And in
comparing 460 to 458HE a little work in 460 was expended compressing gases 10,000 psi more,
expanding chamber and brass, creating more heat,
fighting friction to get gases through funnel;
all because it had to work against shoulder, thus leaving a little less energy to work on base of bullet.Some more energy was expanding and heating.Not a lot.Not enough that necked cases
will go out of style.In my 458 the brass was soft so I couldn't run the 10,000 psi more.And the extra 10,000 psi doesn't translate into all velocity gains, it just shows where some of the energy is used. USED UP IN THE CHAMBER MORE, AS OPPOSED
T0 BULLET BASE WITH MORE AREA UNDER THE CURVE IN
MY CASE BECAUSE OF RIGHT POWDER AND SHAPE OF CASE.Getting more work done on bullet, a little less on chamber, because
the diameter of charge is same as bullet diameter.
And less work on brass in chamber means brass
lasts longer.Most important.

When it comes to cartridge changes there are physical limits, like your example with 264, as
a case that long and skinny would be hard to build gun for, manufacture case,etc.But with my case
it only added 3/4 inch to loaded length compared to loaded length of cases 2.8 inches long.Perfect for #1.And long bolts actions are comong.Again with my soft brass I did as good or better than 460, because my case shape matched
th powder better.Just good circumstances.Ed.

Ed,

So if we have a 460 Weatherby with a 26 inch barrel and your 458 calibre in a 26 inch barrel...what will be the velocity differences with 500 grain Hornadies.

Mike

Mike-About 30- 50 fps.Not enough to put Wea out of business.I would like to see you takt one of
your 460s and replace the 23 inch and dekicker
junk, with say a 28 in heavy tube.And you will see
big gains in velocity, and less recoil.That can get you combination to make better use of other powders.Ed

Still at it, eh? On to ... Oblivion.

Mike375,
A mark V with vertical stack drop box it is, for sylishness sake. Sort of like a Cadillac with tail fins, eh? It would certainly feed most flawlessly, better than a .425 WR.

The CZ deserves a Rigby. Agreed.

DaggaRon

It is a pity that Weatherby do not offer the 378, 416 or 460 in the Synthetic model as that rifle is only about 60% of the price of a Deluxe.

A 416 Wby in that price range would make an interesting alternative to the CZ in 416 Rigby. I reckon Wby would sell a lot of 378s if chambered in the Synthetic model.

In terms of the ownership stakes one plus the 416 Wby in a Mark V has over the CZ 416 Rigby is the Weatherby is the real thing.

Mike

Well, you fellas have made your points, and, it seems like a clash of the titans of sorts. I had, after reading some articles, don't know how old they are, come to the conclusion that .460 Wby was the peak of factory loads. It may have been at some point, but it isn't now, and Mr. Hubel's stuff proves that in spades! Thanks for everything guys, you've been a real help.

On toward Oblivion with this thread!

Mike375,
The cheap plastic stock on the Mark V Synthetic will not handle much of a barrel contour, due to the forend profile/contour.

I do have a take-off 378 Wby barrel that will work in it however. This would be a switch barrel of sorts, from 30-378 to 378 Weatherby Magnum.

The 378 barrel has express sights and a barrel recoil lug, but it is only 22" long, cut down from the 26" factory barrel. I bought it for a song from a guy who couldn't hear too well, kept saying "Huh?" during the transaction, and he had his right arm in a sling. The 30-378 barrel is 28 or 29 inches long with the Accubrake-earsplitter.

Has anybody tried a 500 grain Matchking in either of these Flaminspoutns?