Range Report...458 WinMag-(low & slow)

[Guido4198]

I've been looking for a low & slow "Big soft bullet load" for my .458 WinMag.
Here's what I came up with today at therange. There's a coupla things here that kinda suprised me. Tell me what you think..OK??
These were all fired from my Dangerous Game Rifle. With full house 500 gn. solids it's done well on Elephant and Buff. A Remington .458 Win mag built on what was originally a LH 7mm Mag. 21" Douglas bbl. The slug is an NEI "Badger-Browning", plain base design, cast in 30:1 alloy that scales out 492gn. Sized .459, NRA-Alox lube.
There were all loaded with Win. LR mag. primers. Shot from a rest @ 50 yds.
No "leading issues" observed with any of these loads.

Load 1: 40 gn. IMR 4198- ave. M.V.: 1505 fps. Es:71
Didn't group very well, couple of inches. Otherwise no problems.

Load 2: 45gn. IMR 4198- ave. M.V.: 1666 fps. Es: 5
As above, no problems, but no improvement in group size.

Load 3: 50 gn. IMR 4895, M.V. ave: 1377 fps. Es: 16
This gave by far the best group, 5 rds. with all holes touching.
Sort of the classic,"one big ragged hole"

Load 4: 50 gn. IMR 4895 w/ approx. 2gn. poly-fil. M.V. ave : 1596 fps. Es: 30
Groups opened up a bit from the load without polyfil. I was particularly suprised that the Es increased, and also suprised by the dramatic increase in M.V.

Comments welcome...........
Cheers,
Don

[Chuck 100 yd]

I would guess that the filler is acting as a gasket to seal the bore/bullet giving higher velocity and sometimes it works better than others giving the velocity spread.:confused:

[drinks]

Guido;
Try the Lee 459-405 HB cast of straight ww's, air cooled, with a good lube.
I suggest starting with 25gr 4198 and going up as much as you want, if leading starts, either add 1oz chilled shot per 5lb of wws and water drop or change to 4895 at 40 gr and see if the leading stops, also try the waterdropped with 4895.
Keep the chamber pressure below the yield strength of the alloy and you should be home free.

[Bullshop]

I think that a hollow base boolit and a quick twist 458 is prolly not a good match up. I might be wrond but thats my guess.
BIC/BS