Does anyone have a recommendation for a load for a 458 win mag using a 300 or 350 grain barnes x (or any other premium bullet). I want to use it on a spring brown bear hunt. I just need 2500 fps or so....but am mainly interested in accuracy out to 150 yds. This will be out of a 22" pre 64 winchester barrel. Thanks.

I am using the 350gr Hornady bullet with 70gr of Norma N-200 which gives a velocity of 2525f/s. When I started looking for loads to my 458Win, I mailed Norma and was given 73,5gr as maximum load with 350gr Bullets. I tried up to maximum loads without any sign og high pressure. I got best precsionon using only 70gr ~(three shoots within an 1") so I stopped there
PerN

Palmer
With a 350gr bullet start with 70gr. of IMR 3031, to a max of 75gr.
With a 400gr. start with 67gr. of IMR 3031 to a max of 72gr.
This info is from the Barnes Manual No3.
When I had my 458 I used 70gr of IMR 3031 with 350 and 400gr. bullets.
I do not think I would wand to hunt bear with a 300gr. bullet, even a Barnes X.

70 to 72 grs of IMR 3031 and the Hornady 350 gr bullet is an excellent reduced load.Accuracy falls off a little with loads above that (in my rifle).I was using std Win LR primers also ,not mag primers.

Don't have my manual here, but I just happened to reload some this weekend. All the info you need is in the Barnes manual. I believe the load I tried was 68 gr of Reloader 7 with the 300 gr X. Max was listed as 69, but the 68 seemed pretty mild in my rifle. This was listed as the preferred powder in the manual, as it is for almost all 458 loadings.

By the way, the performance you listed is not a particularly reduced load in a 458 with a 21" or 22" barrel.. It is equal to or somewhat ahead of most starting loads. With the near max load, I got 2460 out of a 21" barrel. I think the max will be something below 2600. Don't count on the long barreled numbers shown in the manuals for a short barreled rifle
One thing I did notice is that the 300 X was hard to load because the bullet fit was so loose in the case. I think if you are going to load these short 300 and 350 bullets, you need to not bell the case mouth as much. I have never had this problem with the Hornady hollow points before. Also, after crimping, the bullets were still pretty loose (they would rotate). I think a decrease in belling would cure this. Crimping was also tough due to the powder charge not filling the case. If my rifle can handle an increased charge, I believe reloading will be easier.

Thanks to everyone for the loads. Now it is time to start trying them!