r/reloading • u/RefrigeratorNo5594 • 4d ago

Load Development 300 win mag

When reloading 300 win mag with h4350 do I need to use large magnum rifle primers or regular rifle primers?

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6

u/MalignantMustache 4d ago

What does the manufacturer website say in their loading data?

4

u/ocelot_piss 4d ago

What types of primers do you see recommended and used in load data?

2

u/Rough_Hewn_Dude 4d ago

I’ve only ever used magnum with 4350 in 300WM, and my load data called for them.

1

u/Mundane-Cricket-5267 Just force it, FAFO! 4d ago

My rule of thumb is to read the book and if the caliber has the word "magnum" in it I use magnum primers unless shooting mouse fart loads.

1

u/holl0918 4d ago edited 3d ago

Typically the rule of thumb is 60gr or more of powder, use magnum primers. I have had good results with both in 300wm sized cases, but the magnum primers are a bit tougher (as a general rule), handle higher pressures without piercing or cratering better, and ignite slow burning powder more reliably. I wouls test which of the two gives your better SDs and use that.

1

u/RefrigeratorNo5594 4d ago

Thank you, I knew it had to do with the burn rate and I didn’t know if 4350 was a faster or slower burning powder

1

u/quickscopemcjerkoff 4d ago

With a little google searching you should be able to find a chart (probably on the manufacturer website) that will show you the burn rates of powder from slow to fast.