Magnum or standard primer with extreme powders?

[crimsoncomet]

Hey guys,
A couple weeks back, I was asking about bullet selection for my 308 for a hunting trip this year. I am itching to start load development. I appreciate everyones advice on the bullet matter. The next question at hand is my primer selection.

I will be working up loads in my dad's 270 winchester with h4350 and 130g bullets, and varget in my 308 with 150g bullets. I decided to go with the extreme line of powders due to the colder temps in canada. These powders dont normally need a mag primers. But, seeing as the temperature might be around 0-30 degrees F or colder, I thought it may be a good idea to work the loads up with the mag primers. What do you all think?

 

[NCsmitty]

Using a mag primer will be fine if you start on the lower side and work up. Be aware that although the extreme powders are supposed to be unaffected by temp extremes, a load developed at 0 and below needs to be checked if shot when temps reach into the 80's and 90's. The worry of course will be an increase in pressure at the high temps in spite of factory claims. It can and does happen, and it's not related to a magnum primer.



NCsmitty

 

[ArchAngelCD]

I agree the Hodgdon Extreme powder line was developed to lessen the worries of it not igniting in the cold. For the most part a Magnum primer shouldn't be needed especially with the calibers you are using where the powder charges are well under 70gr of powder.

Like already said you can use a Magnum primer but follow all the usual loading rules when working up a new load. (not that Magnum primers are that much hotter)