I´d like to know if there is someone here who know about the dimensions of the 460 G&A. Some people say that it has to small shoulder, how high is the shoulder?
When I´m looking to reloading data for 450 Vincent I think that they must have overloaded that cartridge becourse it have allmost the same velocity as 460 Weatherby.

I think that 460 G&A would feed better than 458 Lott or 458 WM, but maybe there is to small shoulder on it. In some country you must have the right headstamp on the cartridge, how to do when you have a 460 G&A or 458 Ultra Cat with 404 Jeffery or 300 Rem Ultra Mag as headstamp?

Maybe 458 Lott would be the best choice.

Anyone who like to help me with this questions?

Best regards
Karl

The Big Bore Forum would probably be the place you'd get the best answers.

Moved to Big Bores from Big Game Hunting. PM sent to Kalle.

Cheers,
Canuck

Of the options you discussed, the .458 Lott is by far the best choice for many reasons.

Because of the headstamp issue, and the possible shoulder issue, I can't see any reason to do a wildcat 45, as there are many excellent factory rounds available. I'm personally fond of the 458 Lott, but agree that it isn't the ideal case design, but very practicle.

If you want a bigger case, then I'd say look at the 450 Rigby or 460 Weatherby. They are bigger still than the 460 G&A, and are factory rounds.

Since you can do a 460 Wby on a low price CZ or a low priced and used 30/378 Wby Synthetic there is no point in the 460 G&A. Years ago there was a point to the 460 G&A when a 460 Wby meant either having to buy a 460 Wby Deluxe or a complex and expensive conversion of a P14 or some Magnum Mauser action.

If you have an action like a Model 70 that you want to use or have to use then I think the 458 Lott will be an easier way to go.

With the 460 G&A the head space issue has maninly centred around the problems if that calibre (or a 458 Ultra) was done as a factory round because of the loose dimensions on factory ammo. That is supposed to be the reason that the 450 Dakota is a 416 Rigby Improved necked up as opposed to the blown out 404 Jeffery which forms the 416 Dakota. But for a reloader things will be different. Although if loaded with 500 grain bullets and a round was slammed into the chamber a few times head space might grow.

You could perhaps get head stamped brass from Quality Cartidge.

Mike

quote:

Originally posted by Kalle:
I´d like to know if there is someone here who know about the dimensions of the 460 G&A. Some people say that it has to small shoulder, how high is the shoulder?
When I´m looking to reloading data for 450 Vincent I think that they must have overloaded that cartridge becourse it have allmost the same velocity as 460 Weatherby.

I think that 460 G&A would feed better than 458 Lott or 458 WM, but maybe there is to small shoulder on it. In some country you must have the right headstamp on the cartridge, how to do when you have a 460 G&A or 458 Ultra Cat with 404 Jeffery or 300 Rem Ultra Mag as headstamp?

Maybe 458 Lott would be the best choice.

Anyone who like to help me with this questions?

Best regards
Karl

Here are some specs from a Dave Manson Reamer drawing that another forum member has:

Rimless, shouldered, with neck, 460 G&A:

minimum chamber length = 2.875"
base diameter = .549"
base plus rim to shoulder = 2.2048"
shoulder diameter = .535"
shoulder angle (each side) = 15 degrees
axial/centerline run of shoulder = .131"
neck diameter = .488"
neck length = .539"
freebore length = .150"
freebore diameter = .459"
leade angle of throat = 1 degree 30 minutes
pilot diameter = .449"

Tolerances for the reamer:
diameters:
+.001"
-.000"

lengths:
+.005"
-.000"

angles:
+/- 10 minutes

The shoulder step per side is (.535"-.488")/2 = .0235" = .024"

That is twice the thickness of an H&H belt, but instead of the 90 degree angle of the belt, it is a 15 degree shoulder.

It will work when fire formed to your rifle chamber, but no commercial ammo maker would attempt to load factory ammo for it.

You can go here to find the Clymer reamer drawing for the 460 G&A and compare it to Manson's:

http://www.clymertool.com/cgi-bin/reamer.cgi

select rifles, rimless, and scroll to 460G&A.

I have reconsidered this folks.

It is total bull hockey that the 460 G&A cannot be commercially loaded. They just don't want to do it for bean counter reasons.

Total BS.

The G&A and Vincent .458's based on .404 Jeffery cases have a totally adequate shoulder.

I am learning.

Something between the Lott and the 460 does make sense, as there is a big jump in case capacity there. The Vincent Short is truely a sleeper, and the loads and velocityies published on this site are reasonable...not hot. If you use RUM brass, you can use a std mag action and save by not having to change the bolt face. Since it will be a custom chamber, the shoulder is fine, just as RIP sad.

RIP,

I have interviewed two manufacturers (one USA and one European) who declined to go to production with .460 G&A projects. Same reason cited by both: too much wiggle room between the spec range for factory rifles and factory ammunition.

Not a problem for the handloader.

jim

Jim,
How in the world do they get by with ever having factory loaded for the 10.75x68mm in days of yore when the ability to meet tolerances was more questionable?

They just don't want to do something they see no adequate market for. Money always dictates. Sales would not cover startup costs.

Consider the 10.75x68mm Mauser:

Shoulder diameter = .4803"
Neck diameter = .4531"

shoulder step per side = .0136"
shoulder angle = 27 degrees 57 min. 29 sec.

This is barely more bump at the shoulder than an H&H belt, and the angle at each side is about 28 degrees.

Only half the shoulder of the .460 G&A but 13 degrees more angle.

The 10.75x68mm Mauser was factory loaded.

Was it discontinued due to poor function or too many misfires?

Ron,

A couple of points, if I may

Firstly, the belt with is not valid. If you wish to prove that it is very easy. Make some shim from a coke tin and put it on the bolt facew it both a belted case and also a rimless case like the 270, 30/06 etc. You will find when you have too much shim the belted case will stop you closing the bolt like you have hit a wall. With the 270 or 30/06 you will have enough camming power to chamber the case and in fact be sizing it to a small degree.

On the issue of bean counters one piece of evidence against that is the 450 Dakota. One would thing the most economical way for Dakota would have been to neck up their 416....especially since they do not claim 2610 f/s with 500 grainers to knock the 460 Wby off its perch.

In the case of the 10.75x68mm Mauser there are two things that might provide the answer. Firstly, back in those days you never had all the legal action etc. Secondly, I think the 10.75x68mm Mauser was never loaded with bullets heavier than 350 grains (347 grains??) and as such the loaded round would not have the same momentum as when loaded with a 500 grain bullet. I thinking here in terms of very rapid bolt closing and this being done several times on the same round many times.

Mike

I did acknowledge the 90 degree brick wall of the belt.

The comparison to the belt is just for mental imagery purposes.

I think you are straining credibility with mention of the momentum difference of 347 grains versus 500 grains as the driving force for sizing down the shoulder in chambering.

My 45 Lapua (.027" step and 20 degrees per side) has little more shoulder than the .460 G&A (.024" step and 15 degrees per side). This is because of the retained Rigby body taper versus the minimal taper of the .404 Jeffery based .460 G&A.

There is a world of adequate shoulder in the 45 Lapua. So is there in the .460 G&A.

But your 45 Lapua is not a factory round.

John S had a 460 G&A and he told me that he sometimes had some headspace issues with. I think the poster Andy that does all the bullet tests moved from a 460 G&A to another version with sharper shoulder.

And again, I think the 10.75 X 68 must also be viewed from the point of view of legal/lawyers etc as compared to today.

Mike

O.K. Mike, I guess lapua is the only brass with a maker to be trusted with such a shoulder. I wonder who the companies were who turned down the .460 G&A, eh, Jim?