Wanting .458 win mag chronograph results of factory

[Nhoro]

I am planning to do a short article/video on loading for and shooting with the 458wm. I think the results will interest a few people.

That will be very interesting. In the end, I have ordered a CZ 550 in 458 win mag. I can get it reamed to Lott if I find that necessary. Currently win mag ammo factory is roughly $12 cheaper than Lott and $22
cheaper than 416 rigby PER ROUND.. Essentially I can shoot 2 or 3x as many rounds per year of win mag. I look forward to your article/video, maybe you could link to it in this thread ? Many reloaders in Southern Africa cant access the right powder to get the velocity up and so seat the bullet out a little to create more powder capacity. SAAMI specs show that the Lott and win mag chambers are different shapes as well as different lengths and that you can seat the bullet out further in a Win mag.

 

[Daga Boy]

Yes, you seat the bullets further out. How far you can go depends on mag length, chamber and bullet. In a CZ550 magnum you should get to about 6mm short of a Lott; however only with longish bullets otherwise you wont have enough left in the case. You need to keep about 1 calibre in the case (say 11-12mm but you can go a bit shorter with light bullets). At max length you will experience feeding problems with blunter bullets so you will either need to shorten the load until it feeds properly or have some work done on the rails and feed ramp. Pointed bullets like the Barnes or Swifts can generally be pretty loaded long without encountering problems. Also look at using monometals like the Barnes or Peregrine in 450gr rather than 500gr.
You should get decent velocities with S321. About 2200fps with 500gr FMJ's but I have yet to chrono.
I have spoken to the guy at Peegrine. He also uses a .458WM and reports V0's of 2300fps with 74gr S321 using a 450gr bullet. (That's rocking).
A friend of mine who does some control shooting uses only a .458 loaded with 450gr Barnes bullets. He assures me that the bullets go pretty much right through an elephant.
Note: You may have to get some work done anyway unless you are lucky as new CZ's frequently wont feed well.

 

[Nhoro]

Thanks Daga boy. Unfortunately, most rifles need a little work, especially with flat meplat bullets. I was at the Zim hunters and guides shooting exams. About 16- 18 people did the practise and there were probably 13 mis feed problems. Various manufacturers. I personally had problems with Ruger 20 years ago. It needed work to feed anything with a meplat. It looks like I can get Hornady factory ammo so will start with that and use reloads for practise. The CZ gives me the option to go Lott or Rigby if I really have a problem. That is interesting about the 450 gr bullets, I mean how much penetration is enough ? I figure frontal brain shot on an elephant would be my worst case scenario. A texas heart shot should not ever be needed while guiding. I think the 458 win mag is perfectly capable of putting down any animal as long as I do my part but perhaps if I were expecting shots on rapidly departing ele's as a hunter, I would think differently.

 

[Daga Boy]

Sorry, correction re COL.
Your mag will take a full length Lott cartridge; but it will not chamber, leaving about 6mm sticking out. This is due the case mouth contacting the end of the chamber.
However if you experiment with bullet seating using a standard 458WM case you should get around 88-89mm COL with a typical 500gr FMJ bullet. This is 4-5mm longer than standard and only 2-3mm off the Lott COL. Actual max COL for a given projectile will depend on your chamber. The capacity increase is significant.
If you use a pointed projectile of sufficient weight then you might end up at 90 or even 91 COL, which is very close to a Lott

 

[Daga Boy]

My rifle is in for repair as the stock cracked big time on my last hunt. (not uncommon with synthetics)
Once it is functional again I will do some testing and publish the results.
I suspect they will show that there is no point in converting to a Lott if one is hand loading.

 

[Daga Boy]

The problems associated with 458Wm are only true of rounds loaded to fit standard / short actions.
See attached pic of 458 dummy rounds with 458 Lott round for comparison. All of these feed perfectly in my Brno.
Plenty V and no pressure issue .

 

[Daga Boy]

Bullets are 500gr Hornady, 480gr Hornady DGS, 450gr Peregrine, 450gr Swift, 400gr Swift. Apart from the 450 and 400gr Swifts all rounds are approx 5mm longer than normal

 

[Nhoro]

Bullets are 500gr Hornady, 480gr Hornady DGS, 450gr Peregrine, 450gr Swift, 400gr Swift. Apart from the 450 and 400gr Swifts all rounds are approx 5mm longer than normal

Thanks Daga Boy. I see that the two round nose solids at the bottom have the canelure seated far out. How did you ensure that the bullets don't move under recoil ? I have seen people using monolithic solids with gas checks so that they can form a firm crimp into one of the gas checks.

 

[IvW]

The problems associated with 458Wm are only true of rounds loaded to fit standard / short actions.
See attached pic of 458 dummy rounds with 458 Lott round for comparison. All of these feed perfectly in my Brno.
Plenty V and no pressure issue .

View attachment 243081

I fail to understand why people try and make a certain caliber what it cannot be.

Seating bullets so far forward to try and compensate for lack of case capacity in order to achieve something that a cartridge cannot do is just asking for trouble. If the thing cannot achieve the velocity with the standard weight bullet of 500 grns then find a caliber that can.

Wait for one of those forward out of canilure seated bullets to set back in the case while in the mag under recoil and see how you gonna sort out any arising issues when the rifle fails as a result.

Reducing bullet weight to achieve the same is just as ridiculous. Rather step down in caliber.

458 WM is a poor choice as a DG back up rifle period.

 

[Daga Boy]

I am not saying its a perfect calibre, but if you have one (as I have had for 20 years) you can optimize its performance.
Exactly how much will depend on your rifle, but with a magnum length action you can get around 10-12% increase in powder capacity with the bullet in place (pre-seating capacity is meaningless) - so your effective load with a 500 gr bullet will be roughly the same as a Lott. (In my CZ the finished 500gr Hornday FMJ COL is a tad over 90mm, so less than 2mm short of a Lott). Note that this type of loading only works with longish bullets as you want to leave a minimum of 10mm and preferably a full calibre (say 12mm) in the neck.
For crimping I swage a groove at the desired position using a Lee factory crimp. You can also use other devices for this purpose - or you can cut a groove using a lathe if using a monolithic.
On the banded bullets (which are now much more popular than standard jacketed rounds with most hunters) and actually better for this type of loading you can just choose an appropriate groove.
Although I haven't had any set back problems I am also considering cementing the bullets in place (as was/is done with some factory loads).
As for the use of lighter bullets, it all depends what you are seeking to achieve. I know one PH who only uses 400gr Swifts in his 458 - but then he is not shooting elephants. 450gr monometals (Barnes, Peregrines, etc) are currently very popular and all reports I have heard have been good. Its worth bearing in mind in this context that 480 and 465 gr bullets were standard in the 450 Nitro.
Where the lighter bullets really come in is that they make the rifle more versatile - i.e. you can use it for shooting plains game. Higher velocity loads are also much better than slow, heavy bullets on cats.
One final thing: I am not recommending a .458WM as a dedicated elephant hunting rifle. In fact its not my first choice as a hunting rifle for anything. However the point is that you can quite easily improve the cartridge's performance to equal or even surpass that of a 450 Nitro - which was the original objective. I would also far sooner have any 458 calibre rifle than any 375 in a charge situation.

 

[IvW]

I am not saying its a perfect calibre, but if you have one (as I have had for 20 years) you can optimize its performance.
Exactly how much will depend on your rifle, but with a magnum length action you can get around 10-12% increase in powder capacity with the bullet in place (pre-seating capacity is meaningless) - so your effective load with a 500 gr bullet will be roughly the same as a Lott. (In my CZ the finished 500gr Hornday FMJ COL is a tad over 90mm, so less than 2mm short of a Lott). Note that this type of loading only works with longish bullets as you want to leave a minimum of 10mm and preferably a full calibre (say 12mm) in the neck.
For crimping I swage a groove at the desired position using a Lee factory crimp. You can also use other devices for this purpose - or you can cut a groove using a lathe if using a monolithic.
On the banded bullets (which are now much more popular than standard jacketed rounds with most hunters) and actually better for this type of loading you can just choose an appropriate groove.
Although I haven't had any set back problems I am also considering cementing the bullets in place (as was/is done with some factory loads).
As for the use of lighter bullets, it all depends what you are seeking to achieve. I know one PH who only uses 400gr Swifts in his 458 - but then he is not shooting elephants. 450gr monometals (Barnes, Peregrines, etc) are currently very popular and all reports I have heard have been good. Its worth bearing in mind in this context that 480 and 465 gr bullets were standard in the 450 Nitro.
Where the lighter bullets really come in is that they make the rifle more versatile - i.e. you can use it for shooting plains game. Higher velocity loads are also much better than slow, heavy bullets on cats.
One final thing: I am not recommending a .458WM as a dedicated elephant hunting rifle. In fact its not my first choice as a hunting rifle for anything. However the point is that you can quite easily improve the cartridge's performance to equal or even surpass that of a 450 Nitro - which was the original objective. I would also far sooner have any 458 calibre rifle than any 375 in a charge situation.

Or just rechamber to 458 Lott and skip all the jargon and risks involved in trying to achieve what the cartridge cannot do.

 

[Daga Boy]

I wont argue with that.
Save maybe for 2 things:
The first is that you will gain very little from a Lott vs long loading a 458 WM when using 450-500gr monometals as actual propellant capacity will be about the same. (This isn't true with conventional bullets, where the Lott is simply a much better, less complicated option)
The second is that that if you are going to re-chamber then the 450 Rigby has quite a lot offer over the Lott. In fact its a difficult cartridge to beat and its a fairly straightforward conversion from .458 in BRNO602 /CZ550 long. You do drop from 5 to 3 in the mag, but how often does one actually shoot 4 shots between reloads?
For those with standard length actions the .458 Sabi is not far behind.
As I said, I don't actually favour the .458WM as a hunting rifle.
But now we are way off the original topic.

 

[ikeda]

So unless I missed something NO ONE has bothered to actually chronograph current fresh factory .458 mag. ammo?

 

[Daga Boy]

I haven't and don't plan to, but people I know who have done so assure me that the Hornady superformance stated V0's are exactly as claimed - i.e. 2150fps with a 500gr bullet out of a 24" barrel.
This is consistent with published handloading data for Varget, Hodgdon H335 and H4895 using a standard COL of 3,310" so I cant see any reason to doubt the veracity.
Note that V0's will vary from brand to brand and that many factory loads do in fact fall short of these figures.
PMP for instance claims 2067 with a 475gr solid. This again is probably right as a max/slightly over-max load of Somchem S321 yields around 2000fps out of a 24-25" barrel. This is simply because S321 is not as well suited to the .458WM case as those referred to above - which is why PMP uses a 475gr bullet rather than a 500gr one.

 

[Timbo]

traveld not so less through Wild- Africa.
Never heard sad things about the 458 Win.Mag. from the hunters there.
The only Tony Arino, he is living in the past.
The effect from the cartridge for 50 years is not to compare as it is today.
Slowly or not,on DG its doing the job on a wonderful way.
Foxi

Though I greatly respect IvW's long experience as a PH,and knowledge of DG firearms, I must agree that the 458WM has come a long way since the caking issues that dogged it 50yrs ago. Today, for a client, I see no problem with the calibre as long as it's reloaded sensibly: the load I use (not compressed) is with 500gr Woodleighs. To date, all the game I've taken with it have been pole-axed. I spoke to a Zimbabwean PH in Zambia last September, and in his experience he positively raved over the performance of 480gr projectiles in the 458 Win Mag. I haven't used this bullet weight, so can't comment. But I've found Woodleigh 500gr RNSN or FMJs work beautifully when loaded within specs.

True it's not a 458 Lott, and there are a lott (sic) of more powerful cartridges to choose from. But in a short action, time has proven the 458 Win Mag is plenty enough for DG.

I bought my 458 before the Lott was commercially available, and because of licensing here it would be extremely difficult to upgrade to the Lott. But that said, I'm very happy with the performance of my 458 Win Mag - and to date, none of the game I've taken with it have complained.

 

[Lance Hopper]

Well, I am Happy to report that I can answer ,Mostley, the OP's question about ACTUAL mv of 458 factory ammo. I say mostly because the ammo is no newer than the 90's, I think. It is winchester 510gr. 458 Win. mag in the white box with orange, red and black logo and letters. The rifle was a Heym 88B double. The throat in this gun is long enough that if you dropped the bullets into the barrels and then inserted the brass, the gun would still close and not seat the bullets into the brass.

So, the right barrel went 2049 fps and the left 2052 fps. The chronograph was an Oehler 35p. Elevation of about 350 ft. and a temperature of about 90 degrees. I would have to believe that ammo produced in the 2000's and in a bolt gun with a standard chamber you would easily be 50-100 fps faster. If I can put my hands on that combination I will do my best to get you those numbers. I hope this helps to at least answer some of what you originally asked!

 

[PeteG]

This is the thread I should’ve posted my chrony readings to... ‍
Ah well!
From the cogswell and Harrison 458wm, we got Winchester super X factory 510gr softs running at 2,060fps.
Hornady 500gr solids at 2,070fps.
480gr Peregrine copper solids at 2,150fps.

 

[Nhoro]

Thanks you gentlemen for your chrono results. It seems that 458 factory ammo has been making 2050 to 2150 for about the last 25-30 years at least. And Lance Hopper, your results also show that older ammois not clumping or deteriorating. It seems that the actual facts of the matter are quite different to the legends.

 

[PeteG]

Thanks you gentlemen for your chrono results. It seems that 458 factory ammo has been making 2050 to 2150 for about the last 25-30 years at least. And Lance Hopper, your results also show that older ammois not clumping or deteriorating. It seems that the actual facts of the matter are quite different to the legends.

My results showed with a 23” barrel. It would be interesting if anyone had a 25” to test. Like the current cz’s. Might show closer to 2100 more consistently.

 

[Nhoro]

I have a CZ 550 with 25 " barrel. Unfortunately I am currently using Peregrine 450 gr at 2250 fps so dont have data on factory ammo. 2 others at my range are using 480 gr hornady solids handloaded with Somchem powder at 2150 fps.(Someone will be along shortly to say it cannot be done but I trust those guys) I also got first hand reports from a guide who did 5 elephant on problem animal control inthe last few years. He said no problems with penetration with frontal brain shots on big bulls. Anyone I can find that has used the calibre on elephant say it does the job. This thread proves that very few people have any facts to back up there prejudice against the calibre. Thanks for actually providing velocities.