So does a 460 Wthby or 450 AR give you the ability to shoot factory ammo in a pinch? It seems like the Lott is the best compromise of all... 458 Win mag factory ammo in a pinch, or load up to Lott levels... can you shoot 460 Wthby in a Lott chamber? or 450AR in a Lott chamber? It seem to me that if you need more than 458 Lott ballistics, should you be looking for more than a 458 caliber... yes/no?

This 375H&H believer wants to know.....

Jack Lott was trying to give his wildcat a boost by allowing rifles chambered for it to also shoot the WM. Fifty years later, that is NOT much of a consideration. Ammunition does not get lost that often anymore, IMHO. The longer chamber would likely drop WM velocities to about 45-70 levels, and Lord knows where the POI would shift to. Factory Lott velocities are a bit optimistic to boot. You have to load your own to get the factory MV. I have a 450 Dakota in a CZ that I load to a chrono'ed 2400fps, about true factory velocity for the Dakota. My load develops less that 48K Psi if pressure is a concern. The Lott is a great cartridge at 2350fps or so with 500gr bullets.

Your logic would follow with "I rechambered my 375H&H to 375 Wbee so I could shoot both in a pinch.".

Rich
CZ's and DRSS

460 Wthby is a factory round.
458 AR is a "wildcat", so there is no readily avialable factory ammo, but there are a few places that will load it for you. In other words, you can't go to your average gunshop and find 458 AR ammo.
You cannot shoot any other caliber in a 460 or 458 AR. The Lott is pretty unique in that area, the only other big game cartridge that comes to mind is the 375 Weatherby and the 375 H&H. You can shoot the H&H in the Weatherby chamber, but not the other way around. Once you shoot the H&H in the Weatherby chamber, it is fire formed to 375 Weatherby and can no longer be used in the H&H chamber..sort of confusing, I know.

If you look at a reloading manual like Hornady and others you will see the dimensions the cartridge cases. Or search on Google etc. I think Wikipeadia has the dimensions

Once you see the case dimensions then all the answers to your question or similar questions will appear.

For the 450 AR check the case dimemsions of the 300 Remingtong Ultra Mag (300 RUM) or 7mm, 338 or 375 RUM as the 450 AR is based on a shortened version of the RUM case.

Here are the dimensions

http://www.stevespages.com/page8d.htm

Apart from the 45 calibres if you check 375 H&H and 375 Wby then congomike's post will be clearer.

quote:

Originally posted by congomike:
460 Wthby is a factory round.
458 AR is a "wildcat", so there is no readily avialable factory ammo, but there are a few places that will load it for you. In other words, you can't go to your average gunshop and find 458 AR ammo.
You cannot shoot any other caliber in a 460 or 458 AR. The Lott is pretty unique in that area, the only other big game cartridge that comes to mind is the 375 Weatherby and the 375 H&H. You can shoot the H&H in the Weatherby chamber, but not the other way around. Once you shoot the H&H in the Weatherby chamber, it is fire formed to 375 Weatherby and can no longer be used in the H&H chamber..sort of confusing, I know.

In my Lott with 23" barrel velocities of several brands of factory 458 Win ammo only ran 20 to 35 fps less then in a 24" barreled 458 Win. About what you would expect with 1" less barrel length.

465H&H

it's good to know you do not lose much velocity. How was poi changed?

Rich

PS: I ahve shot 465's Lott on an old model 70. Beautiful rifle, and very accurate.

quote:

Originally posted by 465H&H:
In my Lott with 23" barrel velocities of several brands of factory 458 Win ammo only ran 20 to 35 fps less then in a 24" barreled 458 Win. About what you would expect with 1" less barrel length.

465H&H

Not surprising when you consider that the SAAMI Lott has such a short throat, compared to the SAAMI/CIP WinMag.

Even adding the .300" extra travel of the WinMag in the Lott chamber, it is still a much shorter jump to fully engraved by the Lott rifling:

.347" + .300" = .647" for the Lott

vs.

1.056" for the WinMag

My standard .458 WinMag 500-grain handloads do about 2150 fps whether from Lott or WinMag chamber. All 24" barrels.

My standard .458 Lott handloads do about 2250 fps in 24" barrel.

If I am getting 100 fps less in a straight-combed, neutral-pitched rifle, then the .458 WinMag is usually only about 2" lower at 100 yards.

Of course, a rifle with some drop and pitch might lob the slower bullet higher by a couple of inches at 100 yards.

POI differences are not great, and can go either way.

It will do in a pinch.
Just like .375 H&H ammo in a .375 Wby chamber.



Posted Sep 5, 8:31 PM Hide Post
I have acquired a copy of Dave Kiff's
The Gunsmiths Book Of Chamber Prints
Pacific Tool & Gauge, Revised 7/2006

It has the SAAMI spec throat for the .458 Lott.
It has the SAAMI spec throat for the .458 Winchester Magnum.

SAAMI .458 Lott chamber throat:

Chamber diameter at case mouth = .483"
45-degree step down to freebore diameter runs 0.012" in length
parallel-sided freebore diameter = .459"
parallel-sided freebore length = .178"
distance from chamber case mouth to end of parallell-sided freebore = 0.190"
throat leade angle = 2 degrees
length of taper from .459" to .448" = 0.15749"
(So let's say 0.157" run of leade to bore/land diameter.)
"Groove Size" = 0.4585"
"Bore Size" = "0.45" (Or is it .448"?)
Total bullet travel in throat from chamber case mouth to fully engaged by lands:
0.190" + 0.157" = 0.347"

The total bullet travel from case mouth to full bearing lands with the .458 Win. Mag. (SAAMI and CIP are same)
and the CIP .458 Lott (same as CIP .458 Win. Mag.):
1.0562" (according to Dave Kiff drawing)
round to 1.056"

Quite a difference between the two .458 Lott throat lengths:

CIP = 1.056"

SAAMI = 0.347"

Isn't the 460WBY a 458 shooter. But it is a lot faster then the 458 Lott.

Weatherby uses the same diam. bullet but faster, the case is considerably fatter. The Lott case is .513 at the belt, The Weatherby is .582