Home Forums Hunting & Shooting Express Rifles and Big Bores Only The great 458 Winchester. Everyone should own one at least once

I have a Lottite calling me "darling" over at AH forum,
so I am having some fun with the facts over there:

hoytcanon,

No need for you to call me darling for your own pleasure, I am not into that kind of stuff.
You may call me "Sir" or just "hey you" will do.

When CIP first homologated the .458 Lott pretender, they tacked the full SAAMI .458 WinMag throat
onto the chamber for 2.800" brass.
For some reason that did not last long after the SAAMI short-throated version came out.
CIP changed to match SAAMI.

SAAMI short throat .458 Lott allowed pressures and velocities to get up to 62,500 psi and 2250 fps with a 500-grain bullet and 3.600" COL.
SAAMI .458 WinMag was doing 60,000 psi and 2200 fps with same 500-grain bullet and 3.340" COL.
That was with same powders (minimal or no compression) in same barrel length of 24". Sure, the SAAMI .458 Lott twist was 1:10"
(an obvious sign of Art Alphin's A-Square shenannigans as a member of SAAMI)
while the SAAMI .458 WinMag has a twist of 1:14".
But that twist difference is insignificant.
Going from 1:14" to 1:7" has been found to cause less than one-half of one percent difference in velocity and pressure by military artillery studies.
Faster twist theoretically may increase pressure and decrease velocity,
I have .458 rifles of both 1:10" and 1:14" and no discernible effects.
I save the 1:18" and 1:20" rifles for being gentler on cast bullets.

If you use the original CIP long-throated .458 Lott in a bolt action rifle meant for 3.6" COL,
you are wasting effective case capacity of the long throat, and at same time imposing the pressure lowering effects of same throat.
You end up with a slow rifle.
Your supposed 2300 fps 500-grainer will not break 2200 fps MV.
I had one of those once, an early CZ 550 Magnum .458 Lott chambered at the factory with the earliest CIP reamer. Shot 500-grainers at about 2150 fps instead of the factory standard of 2250 fps.

It is really silly to take a 2.5" case meant for use in a 3.4" magazine length
then add 0.3" to brass length yet add only 0.2" to magazine length.
Use a 2.8" case in a 3.6" magazine. Ha ha.

The old standard bullet nose projections have to be shortened, bullets made more blunt, or the bullets seated more deeply, or drastically lightened by overall shortening of bullet,
or the brass trimmed short.
It is what it is, maybe some of it not a bad thing.

If you want to use a long-throated .458 Lott, you have to use a single shot to get full benefit.
And then you will probably have to change the powders, use more of a slower powder, get even greater recoil than what is generated by merely increasing bullet MV.

I think the optimum would be a 2.7" case in 3.6" magazine,
like the 2.5" case in a 3.4" magazine.
But even the 2.5"-cased SAAMI .458 WinMag can be loaded in the CZ 550 Magnum or Ruger No. 1
to a COL of 3.780" or 3.760" with a 500-grain TSX crimped in the 5th/last cannelure/groove on that bullet. Individual lots of that bullet have varied by about 0.020" in overall bullet length over the years.
2342 fps with that bullet was my top load in a SAAMI .458 Winchester Magnum chamber with 24-7/8" barrel length, CZ barrel on a Pre-'64 M70 .30-06 action.

The shorter 500-grain TBSS at 3.58" COL does +2400 fps in a 24" barreled Ruger No. 1, factory barrel.
That is a non-SAAMI handload called the .458 WM+ in a SAAMI .458 WinMag chamber.

.458 WinMag rifles X 6 and a 7th in the works
.458 B&M with throat lengthened = .458 B&M+ X 1
.458 Watts Express (.458 WM rechambered for 2.8" brass) X 1
.450 Barnes Supreme (like a .450 Ackley Magnum from the 1950s) X 1
.458/.416 Ruger wildcat X 1
.45-70 Elko Magnum (.45-100-2.6" Sharps with SAAMI .458 WinMag full throat tacked on) X 2
.450 NE 3-1/4" (rechambered .458 Lott stainless/laminate Ruger No. 1-H) X 1
.458/.338 Lapua Magnum (.460 Weatherby barrel set back and rechambered) X 1
.450 Dakota SIG Arms Magnum Mauser 98, Mauser Banner, Prechtl action X 1

The wood on the last one is too pretty to abuse, so I limit it to .458 WM+ equivalent loads.
It weighs 9.5 pounds unloaded, no scope, express sights only.
I have .458 WinMags that are field ready with scope, ammo, and sling that weigh less and are shorter in length.

That may be why I am working on my seventh SAAMI-chambered .458 Winchester Magnum that shoots .458 WM+ handloads,
or the standard Hornady factory ammo , 500-gr DGX-Bonded and DGS, that does 2140 fps from a 24" barrel.
My favorite handload is 400-gr to 404-gr bullet at +2500 fps and 3.38" COL.
Mild for 23" or 24" or 25" barrel lengths in SAAMI-chambered .458 WinMag.
My 7th .458 WinMag will have a 20" barrel to prove the load can be hotted up to 2500 fps in that barrel length: .458 WM+