load development for 300 winmag

[hotlens357]

I am relatively new to reloading magnum rifle callibres.
I have a Howa 300 winmag and all the reloading gear to get started. unlike handguns, magnum rifles need more accuracy with developing a good load.
brass : winchester
bullets : hornady 180g interlock
primers : winchester
powder : somchem s385

where do i start with a good powder charge ? the somchem chart suggests powder weights suitable for PMP brass, any recommendations where i should start when using winchester brass ?

 

[biggdawg]

I am relatively new to reloading magnum rifle callibres.
I have a Howa 300 winmag and all the reloading gear to get started. unlike handguns, magnum rifles need more accuracy with developing a good load.
brass : winchester
bullets : hornady 180g interlock
primers : winchester
powder : somchem s385

where do i start with a good powder charge ? the somchem chart suggests powder weights suitable for PMP brass, any recommendations where i should start when using winchester brass ?

The same start load will work with winchester brass. Winchester brass has good capacity.

not familiar with that particular powder though.

 

[hvychev77]

I'm not familiar with that powder either. For my 300, I prefer H4831sc. I'll load 72 grains under 180 grain Nosler Accubond with a magnum primer. I generally get just around 2900 fps with this and it is extremely accurate. I use Norma brass for this rifle as well. Either way, start slow and get yourself some good scales and several reloading manuals.

 

[FEENIX]

Welcome to LRH and enjoy!

I agree with previous posts. I too am not familiar with S385 but it is a tad faster than H4831 (Powder Burn Rate Comparison Chart @ www.reloadersnest.com).

My Hornady handbook 9th edition shows 74.3 H4831 max for the 178-180 grain bullets with 2900 FPS out of 25" 1:10 barrel, Hornady/Frontier case, and WLRM primer. You can also cross reference it with Search | SOMCHEM; it shows 73.5 of S385 max for the 180 PMP SP.

Good luck and happy safe shooting and hunting.

 

[hotlens357]

thx for all the feedback guys

i got loads of help from my fellow hunters and also referenced the charts on somchem website

loaded a range of charges and off to the range for testing tomoro

 

[Lefty7mmstw]

Good luck on your 300win. The hornady bullets will put a smile on your face when you put them through a critter. We've shot dozens of whitetail and mule deer with the 165 and 180 grain 30 cal. hornady bullets, and they will put the hurt on anything you hit well. They are usually good for a one shot kill and you can usually hear the hit for confirmation unlike some bullets. A bit slower powder, somewhere around rl22 or 7828 may yield a bit more velocity, but the 4831 burn rate will do well also.

 

[Lone Hunter]

In the .300 WM I use IMR 4350 with a 180 Hornady Interlock. Magnum primer. Shoots pretty good. Been thinking about H4831sc for it but I don't use it much anymore(300 wm)I do use H4831sc in my .25-06 and have very good results.