Even a couple or three grains more capacity would be welcomed. I had some great .458 Win loads that were so compressed that they pushed the bullets back out. The compression would get unreasonable just when things were getting interesting. Most published 458 loads for standard weight bullets could be translated as "All the blank powder you can get in the case and still barely seat the bullet". An easier solution than the .458 Improved would have been the .458/300 Win.
458 win mag improved
- Thread starter Royzo
- Start date
Check out the 450 Ackley. My favorite of the 45's. - dan
nowarningshot
CGN Ultra frequent flyer
Sounds like the OP is as unsure about the barrel as all of us. A logical first step would seem to make a cast of the chamber. See how it differs from a standard 458 WM, and go from there. When i think of this caliber, it seems a short range thumper for dangerous/large game. Not really sure what benefit a couple of grains gives you, when you consider probably having to fire form brass. Maybe if one casts there own the fire form loads would make a fun plinker, otherwise the use of expensive projectiles would offset any benefit.
Here's what a Google search produced, for reference.
.460 G&A, .458 Ruger, .458 Lott and .458 Win Mag
".458 WinMag: Pmax = 62366 psi
Overflow Case Capacity: 95.0grs; Usable Case Capacity: 65.4grs
65.1grs H335 = 2096fps, 4879ft-lbs @ 62224 psi – 100% powder burn
.458 Ruger: Pmax = 63004 psi
Overflow Case Capacity: 108.0grs; Usable Case Capacity: 75.1grs
71.6grs H335 = 2168fps, 5216ft-lbs @ 62216 psi – 100% powder burn
.458 Lott: Pmax = 62366 psi
Overflow Case Capacity: 110.0grs; Usable Case Capacity: 78.7grs
74.0grs H335 = 2187fps, 5312ft-lbs @ 62281 psi – 100% powder burn
This seems to be an easy 500gr. 2200 fps round from a 24 in. Bbl."
The 458 ruger numbers are pretty impressive... Kinda about what I thought...
Nearly the same as the 458 LOTT but with a shoulder in it ! RJ
Ardent
CGN Ultra frequent flyer
Henry Ford wasn't attempting a 2% improvement of anything, but rather a revolution.
For those who understand the (pop culture) context, "When in Rome..."
338 Imperial
CGN Regular
- Location
- Chetwynd BC
The 458 Ruger sure looks a lot like 458 Imperial mag , (404 beltless case ) ??
Shorter version I believe. - dan
Had a chamber cast done and found out that the "improved" was stamped on the barrel because it had been reemed out to accept 458 lott casings. I have been told that this may improve performance and easier reloading due to compressed loads in 458 win mag brass. Apparently it will still fire the win mag ammo safely, but I am guessing it would likely affect performance and accuracy.
Now to decide whether or not to put this beast back together or not. I really don't need a thumper like this but it would be interesting. Just a kid at heart!!!
Now to decide whether or not to put this beast back together or not. I really don't need a thumper like this but it would be interesting. Just a kid at heart!!!
The extra length gets Away from some of the compressed loads the win mag uses. Allows you more room for powder to so you can push a 500 gr bullet a little faster.
I load 72 gr H4895 under a 405 gr Remington flat nose bullet and get just over 2400 fps in my 458 wm. It's fairly soft shooting. Like a slug in a hunting12 ga shotgun. Kills things very well. I sight in for 100 yards and it drops about 4" at 200 yards
These bullets do come apart when hitting bear at 15' but the lead core still exits and wound channels are devastating. At 160 yards I got nearly 3' of penetration breaking 6" of spine and all the ribs on one side and breaking the front shoulder. Recovered weight was 369.5 gr. The bullet expanded to larger than a twoonie.
The big thumpers are fun and effective.
A 350 gr bullet at 2600 fps is no slouch either and shoots flat enough for most game
I load 72 gr H4895 under a 405 gr Remington flat nose bullet and get just over 2400 fps in my 458 wm. It's fairly soft shooting. Like a slug in a hunting12 ga shotgun. Kills things very well. I sight in for 100 yards and it drops about 4" at 200 yards
These bullets do come apart when hitting bear at 15' but the lead core still exits and wound channels are devastating. At 160 yards I got nearly 3' of penetration breaking 6" of spine and all the ribs on one side and breaking the front shoulder. Recovered weight was 369.5 gr. The bullet expanded to larger than a twoonie.
The big thumpers are fun and effective.
A 350 gr bullet at 2600 fps is no slouch either and shoots flat enough for most game
- Location
- Somewhere on the Hudson Bay Coast
A .458 Ultra (.460 G&A) is a major upgrade to the .458 Winchester, without using up as much magazine capacity as a .460 Weatherby; a Brno 602 without any modification comfortably holds 4 down, as is the case with my .375 Ultra, but this could be increased to 6 down if you wanted to spend the cost of another rifle on Blackburn bottom metal. My preference runs to bottleneck cartridges rather than tapered, but the advantage the .458 Ultra has over the Lott is admittedly minimal considering the cost involved.
BigUglyMan
CGN Ultra frequent flyer
- Location
- New Scotland
They're not that bad, honestly. I remember when I first bought my #1H. My buddy (since passed away) and I were out busting rocks on hillside about 100 yards away. Offhand, iron sights (big rocks...I'm not ninja!), didn't wear us out too badly. Now a load development session might not be as much fun...
