reduced loads for the 458 Winchester

[swifty]

Have any of you had experience using reduced velocity loads with cast bullets in the 458 Winchester?

I have a 375 H&H Magnum that I shoot cast gas checked lead bullets at velocities ranging from 1200 feet /sec to 1800 feet /sec.I have found an Interarms 458 for a good price and am tempted to try to get similar results with the 458.

Accurate powders makes the 5744 powder which is not position sensititve .

In the accurate Smokless Powders Loading Guide they list a load of 5744 for the 458 Winchester  with a 455 grain cast bullet with 44 grains of 5744
with an estimated velocity of about 1800 feet/sec. They also list a similar load for the 500 grain RN. These are starting loads.

My question is how accurately the big slugs shoot. Will these reduced loads burn all the powder cleanly?do you use any puff-lon or other fillers?

[unspellable]

I have not done much of this with my 458 yet.  There is no reason it shouldn't be quite accurate with reduced loads.  With the straight case and minimal powder space for type, it's a better cartridge design for reduced loads than many of the other big bores.

Any maximum load for the 45-70 in modern rifles will work as a reduced load in the 458.  Nitro for BP loads in the 45-70 may require fillers in the 458.

[captainkirk]

I have used IMR SR-4759 for reduced loads in the 458 WM with good results.  No fillers are needed even at low loading densities (25 grains with a 520 grain Lyman), the loads are mild and can be accurate if the bullets are good.  Of the bullets I have cast, the best ones would group into 1 1/2 or less at 100 yards with the 4759 loads.  I wrote to AA about XMP-5744 a while back, because the published loads seemed stiffer than I wanted to use, but I was interested in trying this powder.  Following is their reply:


Kirk,
You can reduce the load down as much you need with XMP5744.
However, even XMP 5744 will become inefficient at too low performance.
This means that you will observe  some level of unburnt powder.
You will have to experiment yourself, and optimize and compromise between
all factors
I am attaching the published information from our comprehensive no 2 guide
(392pages).
Note: It will be a .pdf file -- (Adobe-Acrobat) If you do not have it yet,
you can download Acrobat Reader 3 or later version (Available Free), from
the website www.adobe.com to view it
NB!!!! Always start at the minimum or "START" charge and gradually (2%
increments) work up towards the "Maximum load".
Regards
Johan Loubser
Ballistic Lab manager
Accurate Powders
McEwen Tennessee


Hope this helps

Kirk