Replicating a factory load

[MT762]

I have never been able to achieve the velocity on the 300 WSM silveretips that the factory ammo can produce without overpressure issues and in all fairness, even the factory loads look over pressured to me. No idea what powder they are using in those loads.

Sometimes with factory WSM loads it seems like they are getting away with colder primers. I shoot a ton of WSM and over the years I have pulled factory ammo and reloaded it with my bullets and powder, but still using the factory primer and found that my own loads with identical cases and magnum primers pressured out way sooner. As best I could guess, some of the factory loads were using large rifle primers.

 

[MallardSX2]

Sometimes with factory WSM loads it seems like they are getting away with colder primers. I shoot a ton of WSM and over the years I have pulled factory ammo and reloaded it with my bullets and powder, but still using the factory primer and found that my own loads with identical cases and magnum primers pressured out way sooner. As best I could guess, some of the factory loads were using large rifle primers.

I am using Large Magnum Rifle primers in my loads. Maybe that is the case in my situation?

I am 250FPS slower using IMR 4064 on my 150 grain silvertip loads. Which is a HUGE loss of FPS in my opinion and I am borderline pressure issues.

Having said that, those factory silvertip 150's has FLAT primers on them. Know that. lol