Magnum primers in .303 OK?

[KDG]

Just primed 50 cases with magnum rifle primers before I noticed my mistake.
I think they should be ok but I'm planning on using up my H335 @ 37gn load and don't know if they would cause any problems with a faster powder.
Any thoughts or suggestions?

Cheers!

 

[PsyEx]

Faster powders will increase pressure in the chamber. I would decrease your Usual load a bit if it is near the upper limit with that powder. Magnums prefer that slow powder. In all honesty I have never had a situation like this.

 

[ben hunchak]

The manufacturer recommends Mag. primers for use with the ball powders ie: H-335, otherwise you would have been wise to fire them off and then deprime. IMHO

 

[Freyr_255]

From what I've read drop the charge by 5% to be safe. Primer brand and type play a roll in pressures obtained and generally speaking magnum primers will increase chamber pressures slightly.

If you're not already running at maximum pressures you're probably fine, but these rounds will most likely shoot a bit hotter.

 

[KDG]

Thanks for the replies everyone.
Min load spec is 36gn.- max is 39.5, I should be ok @ 37gn. I'll fire a couple tomorrow and check for over pressure signs.

Cheers!

 

[mbogo3]

I use magnum primers in almost everything and have for 30+ years.As a lot of gun writers do also...................Harold

 

[Boomer]

I use magnum primers year round in everything other than match ammo. When I lived down south I would only use magnum primers for ball powder, extruded loads over 50 grs, or when the temperature dropped below 0 F. Compared to all that, just using magnum primers universally seems simpler. When I load ammo, I'm never sure of the time of year when I'll shoot it, and logistically it makes more sense for me just to buy a large number of primers at a time. For target shooting things are a bit different though. I don't play that game when its really cold, and the least amount of primer violence which reliably ignites the powder generally produces the best accuracy.

 

[zuke]

Yep your OK!

 

[hakx]

I interchange them (mag / standard) all the time. I don't have the luxury of huge sporting good chains in my neck of woods, and sometimes have to settle with whats available.