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

[Riflecrank]

@Riflecrank what powder and barrel length are you using to achieve 2980 fps?

H4198, 300-grainers, 24" barrel.
The load odonata quoted was from Sir Bob in Ontario. I have duplicated his data.
You can top 3000 fps with the 250-gr GMX from Hornady with H4198 or AA-5744.
That monometal bullet with a plastic tip is tough enough to take it.
Velocities around 2700 to 2800 fps are more sensible since the higher velocity loads only get you about a 50-yard advantage.
Those low BC bullets lose velocity so quickly when started off that fast.

 

[intj]

Is this one of those threads where someone tries to say a 458 Win Mag is better than a 458 Lott because while 458 WM owners are smart enough to seat their bullets longer, Lott owners aren't smart enough to throat their Lotts to take advantage of the 3.850 mag length of a CZ Magnum?



Given these are both pretty straight walled cases, bullet seating depth significantly affects case capacity. So obviously, there is a certain magazine length that will yield the same case capacity in both cartridges. However, when the magazine is long enough, like with a CZ or an M-70 with a Wyatt's box, the Lott definitely has more available case capacity when throated long enough.

You don't even have to have a lathe at home like I do to throat a Lott. You can do it by hand......

 

[CZDiesel]

I have always conceded that the 458 Lott is a more powerful cartridge! But for what? For who?
My 22” 458WM will toss a 500gr round at 2150 to 2170 ftps, so as a client do I need more? I’d argue NO! At over 5200ftlbs of energy and a sectional density of 334 I’m gonna pretty much hammer anything in front of me!
Buuuuuut if I were a PH where I might and probably will be put in the position of cleaning up a mess, well then the added extra juice is worth the squeeze…

 

[Rule 303]

I have always conceded that the 458 Lott is a more powerful cartridge! But for what? For who?
My 22” 458WM will toss a 500gr round at 2150 to 2170 ftps, so as a client do I need more? I’d argue NO! At over 5200ftlbs of energy and a sectional density of 334 I’m gonna pretty much hammer anything in front of me!
Buuuuuut if I were a PH where I might and probably will be put in the position of cleaning up a mess, well then the added extra juice is worth the squeeze…

Lets be honest. If the 458 Win was released years later when there were better powders available then the 458 Lott would most likely not see the light of day.

Having said that bear in mind that a 458 RUM may have turned up, just because they could and the 450Rigby would most certainly have come on the scene. Now if you want extra horse power, and I do not think it would be needed, that would be the way to go.

Not trying to hi jack the thread gents so lets stay on topic.

 

[Riflecrank]

Yep, you have to rechamber a SAAMI .458 Lott with a longer throat to make it capable of what a SAAMI .458 WinMag chamber can do in a CZ 550 Magnum.
I have a CZ 550 Magnum with a SAAMI .458 WinMag chamber and can load it to longer COL than a SAAMI .458 Lott can accept.
Keep in mind that when CZ first stared chambering the old original CIP .458 Lott homologation,
they used the same throat as on a SAAMI/CIP 458 WinMag, so there was way too much throat for a 3.8" mag box. Eventually CIP and CZ rvised to current SAAMI .458 Lott.
Here is what I can run through the magazine of the CZ 550 Magnum .458 WinMag, using a longer call than will chamber in a SAAMI .458 Lott, with 500-gr TSX Long Tom bullets.
Feeds great in the .458 WinMag CZ 550 Magnum:

All the COL's above work in a SAAMI .458 WinMag, with the 500-gr TSX, just barely.
COL of 3.780" is going to jam in the throat of a SAAMI.458 Lott, unless you fix it by using a SAAMI .458 WinMag reamer.
Yes, easily done by hand. Even a caveman can do it.
Unfortunately I have two rifles that started life as .458 WinMags but got re-chambered to .458 Lott and .458/.416 Ruger-Winchester-Throated.
So I have one .458 Lott Special. How silly of me.

You have to trim the 2.800" case extra short to make that 500-gr TSX fit into SAAMI restrictions for a .458 Lott.
At deepest seating of the 500-gr TSX bullet in a .458 Lott:

2.800" brass length + 0.830" nose projection = 3.630" COL. Uh oh.

 

[Riflecrank]

 

[Riflecrank]

 

[intj]

Yep, you have to rechamber a SAAMI .458 Lott with a longer throat to make it capable of what a SAAMI .458 WinMag chamber can do in a CZ 550 Magnum.
I have a CZ 550 Magnum with a SAAMI .458 WinMag chamber and can load it to longer COL than a SAAMI .458 Lott can accept.
Keep in mind that when CZ first stared chambering the old original CIP .458 Lott homologation,
they used the same throat as on a SAAMI/CIP 458 WinMag, so there was way too much throat for a 3.8" mag box. Eventually CIP and CZ rvised to current SAAMI .458 Lott.
Here is what I can run through the magazine of the CZ 550 Magnum .458 WinMag, using a longer call than will chamber in a SAAMI .458 Lott, with 500-gr TSX Long Tom bullets.
Feeds great in the .458 WinMag CZ 550 Magnum:

View attachment 648753

View attachment 648754





View attachment 648777
All the COL's above work in a SAAMI .458 WinMag, with the 500-gr TSX, just barely.
COL of 3.780" is going to jam in the throat of a SAAMI.458 Lott, unless you fix it by using a SAAMI .458 WinMag reamer.
Yes, easily done by hand. Even a caveman can do it.
Unfortunately I have two rifles that started life as .458 WinMags but got re-chambered to .458 Lott and .458/.416 Ruger-Winchester-Throated.
So I have one .458 Lott Special. How silly of me.

Yes, any of those options are exceedingly simple. Hand throat an existing 458 Lott, bring it over to my house and we will throat it in the lathe, or just use a Lott reamer with the freebore you want. Also, rechambering a SAMMI 458 Win works well too.

We do this type of stuff everyday in
our ship and I also do it at home. Though for my Lott I am borrowing a properly throated Lott reamer.

I don't think everyone understands just how much short seating can affect case capacity. The 458 Win Mag / 458 Lott throating show this well. As does a long throated 300 WSM. A 300 WSM with a long throat and then a +P or Bore Rider can get you 2900 fps with a Berger 215 in a 22-24" barrel.

 

[Riflecrank]