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I have the finish reamer for the 458 Express on hand here for a someday after I get the thirteen dozen projects currently in the works finished up. Anybody ever really get their list done around here?

/

Alf,
Thank you very much. Great pictures and text.

Would you have any ft/lbs & fps on the Express?

Jerry

45Nut,

Thank you. Let us know how that project works out when you get to it. There's a saying in our maintenance shop at work..."Once you hit 40, all that stuff that you bought with intentions of doing should be thrown out. It'll never get done." Of course this is very, very annoying to the Mrs.

Jerry

Alf, I assume the 602 or CZ550 magazine is long enough to accommodate the 458 Express? Where does one get brass?

/

Alf,

The Lott cases I have are 2.80 inches long, not 2.85 like I said in my previous post. The OAL of one of the Lott cartridges is 3.63". It fits well within the 3.85" magazine box.

If the 3" case is really 3.0 inches, the 3" case and any normal bullet (in my example 3.852") will not fit in the 3.85" magazine box.

Obviously it can be made to work by trimming the cases back to the necessary length to get the case and whatever desired bullet into the magazine box.

My Lott loads were highly compressed to get the 2300 fps, and the 3" case would probably alleviate that but I doubt that it would have any noticable affect on pressure, for equal bullet velocities.

Hey, if the CZ's have a long throat, maybe guys have a 3" Express and don't know it.

I tried to 3" cases out of SA without success. Maybe that situation has changed. Until I see them at Cabelas the cases are more like maybe than reality.

I didn't realize that the Lott was a "problem" cartidge. I was under the impression that one could achieve 2300 fps with a 500 grn bullet quite easily without excessive pressure. Was I wrong?

No!

/

Will is quite right in that a 3.81 inch cartrridge OAL WILL NOT WORK IN A STD CZ550 mag. Period! The mag box can be enlarged by serious filing to 3.850 and that may be just enough to work.Maybe!!! Believe me the mag boxes I've personally modified will not exceed 3.850. The feed ramp WILL also have to be slightly modified to accomodate this length cartridge.This is exactly why the .600OK was held to 3.650 OAL and is problematic with woodleigh solids.-Rob

/

Alf,

Before you go off the deep end, for most 500 gr. bullets I figure the case is going to have to be trimmed back a few hundreds if the bullet is crimped in the cannalure and going to fit in the magazine. How about a "nominally" 3" case?

I been using H4895 working up loads to 2300 fps in my Lott and have yet to see any outward signs of pressure using the Barnes 500 grain TSX bullets. I still have some more testing to do but I do not see 2300 fps as a problem yet.

The load I took to Africa was a nominal 2250 fps with absolute no pressure signs and worked fantasic on the Buffs I shot. I am now seating my bullets out to 3.640. The CZ Lotts and I am told the 458 win. mag. have a significant amount of "freebore" which premits seating the bullets out further than factory loads. At this stage it seems that seating the bullets out to that length has made bullet seating easier and eliminated some powder compaction while improving accuracy...however still working on it.

/

Hello Big Bore Hunters,



Alf is absolutely correct in what he put up on the board. Why argue in the face of all the evidence. I will just make a few points as I know the 458 Express very well, and Prof. Koos Badenhorst is a personal friend of mine.



a)SABS testing shows undue high pressure with SA powders (S321)when one attempts to achieve 2,300 fps.



b)To achieve 2,300 fps with S321 means you have to go for a compressed load with a ball powder and the risk of caking is unacceptable in a DGR. Compressed loads should not be carried over to the next season, not even with extruded powders in MHO. Compressed loads are out with me.



c)A duplex load of S335/S365 (fast/medium slow)works just perfect to fill the case with a resultant low pressurre of just under 49,000 psi done at SABS with the CIP method of pressure. testing. The slow powder should be at the primer end to ensure a slow peak pressure curve, and then the fast powder can take over to accelerate the speed down the barrel to still achieve your desired velocity.



d)From a safety point of view in tropical climates of Africa the 458 Express is far better than the 485 Lott. However, CZ has adopted the 458 Lott as their DGR offering in line with Ruger to compete on an equal footing. My choice would be the 458 Express due to pressure considerations. (404 Jeff is may favourite for obvious reasons).



d)Prof Koos loads to 2,274 fps, which is as high as one wants to go and still be at a low pressure - any additional velocity is UTERRLY USELESS. All the old British big bores ran between 2,125 fps and 2,150 fps and was adequate, BUT the emphasis was always on low pressure and not on velocity - take note!



e)The 458 Lott should be loaded to 2,150 fps with SA powders to make it more safe, but I still don't like the pressure of around 60,000 psi. I will not go with a load between 62,500 to 66,500 psi.



f)In addition, a Lott should not be buildt on a std K98 action that has been modified (ie weakened), as the pressure and back thrust is too high for my comfort - the ZKK action is much more ideal (ie longer) and stronger (modern steel and tougher to counter lug setback). Long cartridges need long actions - that's why they were created in the first place.



Well that is it.

Facts from Truveloshooter, you can bet on that!

Not so fast.....



I don't know that compressed loads are bad, other than over the years the powder can cake. If you avoid that, I don't see the problem. When I was loading for the Lott, they were highly compressed (about 2 mm or about 0.1 inches), but never saw any signs of high pressure (admittedly, unscientific evidence).



I am curious as to how the pressures quoted were determined. I have seen discussions of the strain gage methods, but I doubt these are precise but rather approximate based upon assumed barrel mechamical properties and approximations of barrel dimensions.



In the scheme of pressure, I do not see the significance of the differences in pressure, such as the comment between 60,000 and 62,500 psi, unless near the yield strength of the barrel, bolt lugs, or whatever else might go boom!



The difference in case lengths might be 0.2" (3.0 compared to 2.8 inches, for the Lott cases I have) but the practical increase in the length of cases between the Lott and the Express is only 0.15", or less, in order for it to fit in the CZ magazine box. This would be enough to prevent having to "highly" compress the Lott loads I used. One could sneak around the compression problem by just not seating the bullets as deep and forgetting about crimpimg or cut a small crimpimg cannalure a 0.1" further down on the bullets used.



Assuming these extended bullets allow closing of the bolt, one could roll there own modified Express without worrying about finding cases or reamimg out their Lott chambers.



And as to what velocities are desired or necessary, these forums are full of those arguable statements!



Thanks for your input.

/

I did not understand the following lengths of the puts 458 Expresses of the cases is which these east the basis to form them

I did not understand the following lengths of the puts which following cases is bases it to form them?

458 Dakota
458 Watts
458 Lott

Alf,
the case capacities listed don't match anything I have seen. For example, a 458 win is a nominal 95gr empty, 75ish grain with a bullet... and the lott is 110ish empty and 88ish with a bullet (woodleigh soft)

assuming the same bullet, set out to 3.81" in a lott case (same internal effective capacity) that give us 97.7 gr of useable case...

about the same as the lott over the winmag (directionally 10-11 gr)

and the 458 AR is pretty close to splitting the 458lott to 457 express difference... and in a standard lenth action (92gr after bullet is in place)

Additionally, your picture of an express in your brno appears to be under .050" clearance, and as a DGR,could cause an internal mag jam. if your pictures are clear.

quote:

Originally posted by tera:
I did not understand the following lengths of the puts which following cases is bases it to form them?

458 Dakota
458 Watts
458 Lott

Tera,
order yourself a cartridges of the world book.

asking, REPEATEDLY of case lengths, when they are IN THE THREAD is getting rather annoying

J

Alf,
thanks for clearing that up.. my "point" (and it's really just camp fire talk) is that the capacities didn't line up with anything I had seen...

the point on the monos is VALID for all bullets.. they work great, but eat up tons of capacity

The 458 ackley (if made 3") would probably solve all this, as it has a neck "for sure" to provide extra tension...

jeffe

T/

Alf,

Thanks for reviving this topic. It is always a case of eating your cake or having it.

I suspect a big motivation for monometal bullets is that they are cheap to manufacture. The blunt noses reportedly give better penetration but coincidentally are cheaper to make! Jacketed bullets could have more than typically blunt noses if someone wanted to make them.

The 458 Lott vs. all the other 450's is just the choice between magazine capacity and bullet velocity. More velocity requires bigger cases and the trade-off is fewer rounds in the magazine.

The 500 gr. bullets at 2300 fps gives about 5800 ft-lbs of muzzle energy and is a thumper, especially the recoil. Anything greater than that eliminates 99.99% of hunters and gets one out into ether land.

I'm not opposed to experimentation but 500 gr at 2300 fps is just good enough, if not more so.

quote:

Originally posted by Will:
I suspect a big motivation for monometal bullets is that they are cheap to manufacture.

Will,
they aren't cheaper... by a long shot, due to cost and "denisty" of materials AND that cnc machinery is pretty spendy...

remember, a pound of copper is several TIMES (yesterday .. $2.22/lbs ve $0.56 (lead) -

and you have FAR more waste in cnc turning bullets than jackets and cores...


lastly .. one can buy an entire manual/semi automatice presses and trimmers and dies for the cost of one cnc lathe... and that lathe makes bullets one at a time.


jeffe

quote:

Originally posted by jeffeosso:
Alf,
the case capacities listed don't match anything I have seen. For example, a 458 win is a nominal 95gr empty, 75ish grain with a bullet... and the lott is 110ish empty and 88ish with a bullet (woodleigh soft)

assuming the same bullet, set out to 3.81" in a lott case (same internal effective capacity) that give us 97.7 gr of useable case...

about the same as the lott over the winmag (directionally 10-11 gr)

and the 458 AR is pretty close to splitting the 458lott to 457 express difference... and in a standard lenth action (92gr after bullet is in place)

Additionally, your picture of an express in your brno appears to be under .050" clearance, and as a DGR,could cause an internal mag jam. if your pictures are clear.

quote:

Originally posted by tera:
I did not understand the following lengths of the puts which following cases is bases it to form them?

458 Dakota
458 Watts
458 Lott

Tera,
order yourself a cartridges of the world book.

asking, REPEATEDLY of case lengths, when they are IN THE THREAD is getting rather annoying

tera

Les raison de la coller il ne doit pas vous fâcher car mon but est de tester de nouvelle cartouche car tout les calibre standard qui son représenter par la C.I.P ?

Au départ ces même standard son née comme des WILDCAT qui on été retravailler !

Est vous pouviez faire un petite compréhension en mettant des dimensions de la plupart des cas que vous former cela peut me donner les informations pour mois même est d’autre personne qui son enregistrer ou de passage .

Mon but n’est pas de perturber votre forum

We are almost 3 years on since the last post, does anyone have any new info or feedback on this cartridge?

Thanks