I was reading my Ken Waters Pet Loads today for the 458win.mag. and Mr.Waters gave these results/pet loads for the 400grian speer FN bullet which iam intersting in loading in the 458 for deer/bear/boar/varmints/etc,.The Powder is imr-3031 and iam asking ...do these loads sound reasonable/safe pressure wise in the 458wm at the reduced loads he offers.Keep in mind The Max load listed for the imr-3031 for the 45-70 Ruger number #1 is 55.gr. for 2,053fps.Ken also recommends these loads for the 458 win mag.
1.Imr-3031 56.0gr.-1564 fps=Reduced Pet Load
2.Imr-3031 60.0gr.-1766 fps=Reduced Pet Load
3.Imr-3031 64.0gr.-1943 fps
4.Imr-3031 68.0gr.-2041 fps
5.Imr-3031 70.0gr.-2071 fps
6.Imr-3031 71.0gr.-2108 fps

Does this 56.0gr.& 60.0gr.reduced loads look like it will be fool proof safe in the 458 with the 400gr.speer bullet & imr-3031 or could i get hangfires??I have no experiance with this powder ...but trust Ken Waters to be a expert on reloading..I plan on useing the cci 250 magnum primer or the winchester WLRM and i also have some federal 215 match Primers..What would you recommend for a reduced starting load & would you take this powder charge down that low in the 458 case?Iam thinking somewhere between 60. & 68.gr. I will find a sweet spot?Iam already getting 1445 with the 30gr.sr4759 load so the 56.0gr.load should have a safe pressure on the low end of this scale of IMR-3031 charges?Am i reading this right?I want to cook it a little faster ,but work up and see how it groups at different charges,seems like a lot of times the lower charges will be the most accurate/but not always...Thanks for any help or ideas

The 56 grain load is about a 25% reduction from the max 71 grainer. 3031 is a medium-burning powder, so I'd expect that it would still be safe. Though, I'd expect pressures to be a bit on the low side.

I wouldn't expect hangfires with these.

I personally prefer IMR 4895 in the .458 Win to 3031.