458 Win Mag vs 458 Lott....The facts

[TOBY458]

I read a lot of debates on this subject, so I thought I'd share some findings with you, based on what my loading manuals have to say.
I hear the Lott is way better than the WM because of the 300fps advantage.
My findings show only a max of 143fps difference with top loads in each. And most average loads show less than 100fps difference.

The other argument is the Lott doesn't have the problem of compressed loads.
Take a look at the load densities. They are almost identical in this department with top loads.

Here's what my manuals have to say.

As you can see, not a huge difference in velocity between the two. The gap begins to widen a little more with Barnes mono metal bullets. Also note the very similar load densities. The Lott takes quite a bit more powder (more recoil) to attain only a small real world advantage.


Top loads for WM vs top loads for Lott.

Nosler 500gr. Partition
WM 2092fps 68gr H335 LD 108%.
Lott 2209fps 79gr RL15 LD 109%
115fps difference.

Swift 500gr A Frame
WM 2116fps 69gr H335 LD 110%
Lott 2233fps 80gr IMR4064 LD 105%
117fps difference.

Swift 450gr A Frame
WM 2292fps 77gr H4895 LD 105%
Lott 2378fps 84gr H4895 LD 103%
86fps difference.

Barnes 500gr TSX
WM 2040fps 67gr TAC LD 105%
Lott 2183fps 76.5gr TAC LD 103%
143fps difference.

Barnes 450gr TSX
WM 2242fps 73.5gr TAC LD 105%
Lott 2366fps 81.5gr TAC LD 101%
124fps difference.

 

[Don458]

Here is the data I have been following take in mind that this is not a Compressed load ! I have tested this in 90 degree weather with no problems. 2160 fps av with 500 gr horn jrn

 

[Don458]

H335 is the go to powder for the 458wm

 

[TOBY458]

View attachment 287586 Here is the data I have been following take in mind that this is not a Compressed load ! I have tested this in 90 degree weather with no problems. 2160 fps av with 500 gr horn jrn

Looks like a good load. I wonder how the newer bonded Hornady bullets perform on game?

 

[HWL]

I calculated this load with QuickLoad….

It developes 78607 psi……..and 2311 fps….. 24" barrel

Not sure I want to have this in hot temperatures, Africa has to offer.


HWL

 

[Don458]

I calculated this load with QuickLoad….

It developes 78607 psi……..and 2311 fps….. 24" barrel

Not sure I want to have this in hot temperatures, Africa has to offer.


HWL

How can this be ? Chronograph shows 2150 -2160 fps constantly. I am not arguing i am asking. ? I have fired approximately 200+ of theses load with no pressure problems or signs .And no extraction problems whatsoever. I also have a 450gr barnes solid load with re 7 that avg 2260 fps . Area i shoot is a sand pit , probably not on the levels of Africa but on a 90 +degree day it is brutal. I always try to imitate situations I may be shooting in .

 

[TOBY458]

I wonder why evertime rifle pressure gets mentioned, outdoor temperature is mentioned as well. With today's powder, there isn't much to worry about in regards to ambient temperature. Also, if you're hunting in SA, the temp is usually very mild. I'm sure it gets scorching hot in some parts of Africa during summer, but how much hotter does it get there than it does in some parts of the USA?

 

[Don458]

I guess it’s been pounded in our heads for so long . I am also getting use to a kind of temperature that I may encounter, if I ever get over there (which looks pretty good now) I would not want my physical condition hinder me so I practice in extremes, also raising heart rates . But again my question about velocity? How can it be ??

 

[Don458]

I guess it’s been pounded in our heads for so long . I am also getting use to a kind of temperature that I may encounter, if I ever get over there (which looks pretty good now) I would not want my physical condition hinder me so I practice in extremes, also raising heart rates . But again my question about velocity? How can it be ??

How can i get this chrono readings consistently

 

[HWL]

How can this be ?

I have absolutely no idea…..

The only message one can have is to be very carefully…

Do you have any chance to check the load in a pressure barrel?


HWL

 

[Dr Ray]

Is that right? 78697 psi??
Seems mighty high to me!

 

[PeteG]

@spike.t can I shoot your 458lott through my chronograph and check the actual speed for comparison?

 

[spike.t]

@spike.t can I shoot your 458lott through my chronograph and check the actual speed for comparison?

Mmm..... Any excuse to shoot it.....

 

[TOBY458]

How can this be ? Chronograph shows 2150 -2160 fps constantly. I am not arguing i am asking. ? I have fired approximately 200+ of theses load with no pressure problems or signs .And no extraction problems whatsoever. I also have a 450gr barnes solid load with re 7 that avg 2260 fps . Area i shoot is a sand pit , probably not on the levels of Africa but on a 90 +degree day it is brutal. I always try to imitate situations I may be shooting in .

If you look at the loads I listed, 75.5 gr of H335 is quite a bit more powder than the Swift or Nosler take for their 500gr max loads, and those loads are already running 110% LD. How deep do you seat your bullets?

 

[ldmay375]

Toby, from the manuals and reading that I have done, 100-150fps difference is what I would expect. That is with standard cartridge lengths and factory barrel chambers/throats.
I have a 458 Win and a Lott. The Winchester is in an Interarms and the the Lott in a CZ that has had some work by AHR. Both set in the safe, perhaps if they were stainless I would have more interest. I prefer the more compact package of the 458 Winchester.
I suppose it boils down to if one wants that extra 100-150 fps. Or wants the Lott for Winchester velocities at slightly less load densities.
My intent was to shoot 400 grain monolithic bullets in both for here in Alaska. I wanted the extra 100 fps. I lost interest after using the 416 Ruger with 350 grain TSX.
I look at the Lott compared to the Winchester as I do the 340 Weatherby compared to the 338 Winchester. I think the average fps difference is about the same 100-150 fps. There is a difference, but does it matter for my use.

I read a lot of debates on this subject, so I thought I'd share some findings with you, based on what my loading manuals have to say.
I hear the Lott is way better than the WM because of the 300fps advantage.
My findings show only a max of 143fps difference with top loads in each. And most average loads show less than 100fps difference.

The other argument is the Lott doesn't have the problem of compressed loads.
Take a look at the load densities. They are almost identical in this department with top loads.

Here's what my manuals have to say.

As you can see, not a huge difference in velocity between the two. The gap begins to widen a little more with Barnes mono metal bullets. Also note the very similar load densities. The Lott takes quite a bit more powder (more recoil) to attain only a small real world advantage.


Top loads for WM vs top loads for Lott.

Nosler 500gr. Partition
WM 2092fps 68gr H335 LD 108%.
Lott 2209fps 79gr RL15 LD 109%
115fps difference.

Swift 500gr A Frame
WM 2116fps 69gr H335 LD 110%
Lott 2233fps 80gr IMR4064 LD 105%
117fps difference.

Swift 450gr A Frame
WM 2292fps 77gr H4895 LD 105%
Lott 2378fps 84gr H4895 LD 103%
86fps difference.

Barnes 500gr TSX
WM 2040fps 67gr TAC LD 105%
Lott 2183fps 76.5gr TAC LD 103%
143fps difference.

Barnes 450gr TSX
WM 2242fps 73.5gr TAC LD 105%
Lott 2366fps 81.5gr TAC LD 101%
124fps difference.

 

[Red Leg]

Do not worry about African heat anymore than you do Texas or Arizona heat. It is a vestigial concern from the time when Brit’s took cordite loads to Africa.

 

[Shootist43]

Just for giggles I ran the following through my QuickLoad program. 458 WM w/a 24" barrel using a 500 gr Swift A Frame and 69 Grs. of H335 powder: 97.4% LD, 75,329 PSI (P-Max is 62,366), 2211 FPS. Something seems to be amuck here guys. Toby's question re. seating depth need to be considered.

 

[Ridgewalker]

Not sure how valid QuickLoads is vs real world testing. IE, my 375 H&H 250 gr load is a couple of grains below Barnes manual max. According to QuickLoads it is way over max pressure. It has never shown any of the standard over pressure indications and I have shot it near 30F and 95F extremes. Of course every rifle is a bit different dimensionally as well as structurally.

 

[Don458]

If you look at the loads I listed, 75.5 gr of H335 is quite a bit more powder than the Swift or Nosler take for their 500gr max loads, and those loads are already running 110% LD. How deep do you seat your bullets?

For the Hornady 500 gr rn interlock COL is 3.318” which feeds great in my rifle I am using 76.5 grs of H335 I probably can seat out to 3.340” as stated in manual , but this is working fine . I don’t believe that the quick load data is correct as this is a verified load from Hornady

 

[Shootist43]

QuickLoad has its' limitations for sure. For some calibers and powders it is spot on, for others maybe not as good.