458 win mag 250gr Hornady mono flex H4895 load data

[Mountaineer]

Has anyone loaded their 458 win mag with 250 grain hornady Monoflex bullets using H4895. I’m looking for the max load, but will load down from there to get a load that is light enough for my daughter to shoot. Thanks

 

[Hunter4752001]

I would have thought that H4895 wasn't suitable for a projectile that light in the 458 WM. In fact I'm not sure you'll find much data for anything that light. H4198 seems to be more appropriate to light projectiles in 458 WM. The Hornady 10th edition manual lists a max load of 50.3gr of H4198 behind a 300gr HP with a vel of 2100fps. I think this load is limited due to the design specification of the projectile. I've used much hotter loads with a 300gr monometal projectile.

An alternative approach may be to research some Ruger level loads for the 45-70 and work up from there.

 

[Mountaineer]

Thanks!

 

[Fryeguy]

Be careful loading light with h4895 in straight wall cartridges. I tried it with my 9.3x74r, light 232 bullets and the minimum charge from a 250 grain bullet I had found. I would get hang-fires. Too much case capacity, and it wasn’t filling case enough in front of primer. I suspect it might be same in the 458 . Better off using existing data and using lightest load in manual for that particular bullet,

 

[michael458]

I would have thought that H4895 wasn't suitable for a projectile that light in the 458 WM. In fact I'm not sure you'll find much data for anything that light. H4198 seems to be more appropriate to light projectiles in 458 WM.

Correct on all counts............ H4895 is too slow for light bullets in 458 Winchester. H4198 is the best, followed by RL 7 and IMR 4198.

This is 458 Winchester Data I did in 2013 and 2022 with the 250 CEB Socom Raptor. Keep in mind, 2013 data was done with 24 inch barrel, 2022 data done with 20 inch barrel.

Also, the 250 Hornady will come apart at these velocities, it needs to be kept BELOW 2400 fps at the muzzle. And much better if you are around 2200-2300 fps. For this I always found IMR 4198 perfect for light loads, in most all big bore rifles. As @Hunter4752001 suggests, 50/IMR 4198 would be a good start to look for this lower velocity with this particular bullet and go from there. You need not worry about fillers or anything else with IMR 4198 and these lighter loads.