.458 Win. Mag.

[cottonmouth]

I have a box of 420 grain Cast Performance bullets with a gas check and need some data. I tried 65 grains of IMR 3031 but this load shot around a 3-1/2 inch 100 yard group. I have shot a 350 grain Speer Hot Core soft point on top of 75 grains of 3031 and it did just over an inch @ 100 yards which is just fine for me. The rifle is a No.1 Ruger by the way. I thought about backing the load down to 60 grains and see if the 420's would shoot any better, any sugestions?

J.B.

 

[Grumulkin]

You need to start at the lower charges recommended by your reloading manual and work the load up in increments. You will probably find that the groups start wide, get smaller and then with higher loads start to widen again. The preferred load is where the groups are the smallest. It should go without saying that you check for pressure signs with each load increase and don't exceed recommended maximum loads.

In a case the size of a 458 Win. Mag., you should not reduce charges below that recommended in the manual or you may get hang fires.

 

[db_tanker]

grumulkin speaks true...

I don't have a 458...but the 45-70 presents a similar problem with a large case cap and certain powders...

3031 is a good choice but you should also possibly look for loads using RL-7 and AA-5744, both somewhat bulky stick powders...also IMR-4198 might be worth a try.

I use all these in my 45-70 and have had good luck with all.

D

 

[Jim Watson]

.458 Win Mag has a long chamber throat to give the 500 gr FMJ a running start. This does not make it a great cast bullet rifle. You can probably adjust things and do better than 3 1/2" but you may not do a lot better.
Look in a Lyman manual for cast bullet load data.

 

[cottonmouth]

.458

Thanks for the input, I need to invest in more loading manuals.

J.B.

 

[Murphster]

Try this:

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=504354

Pretty much all the data in one book.