300 wsm with large rifle primer

fishlonely

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Hi guys, I could not find winchester large rifle magnum primer(WLRM) from local store so I tried large rifle primer (WLR). I will use this rifle for moose hunting so I only reload Hornady 180gr soft point. With 64gr H4350, I usually get 0.6 to 0.8MOA with 5 shots. I thought it's ok. So any friend here can tell me what kind of group I should expect if I use magnum primer? And any comment are welcomed. Thanks.

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I have no idea what a magnum primer would do for your groups....it may tighten them up with that charge, or because they burn hotter, may actually raise pressures enough to open up your group. I've been told by a few reloaders with more experience than I that they don't bother with magnum primers unless the charge weight is 70 gr.'s or higher. I use WLR for my .270 WSM and find they allow for good grouping. I've also heard a lot of guys say WLR primers are the hottest LR primer on the market....so if they're hotter than all the other's, and they work well in your rifle already, why change a good thing?

With lighter bullets, and subsiquently more powder, you may find the WLRM primers work better.
 
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Your barrel likes that velocity and bullet!, you could end up opening it up a bit with different pressure. A magnum primer will burn a bit hotter to a point that may up the pressure, and may or may not effect the groups somethng you will have to tell us with that gun.

I am going with Gatehouse, why bother, those are fantastic groups with a hunting bullet
 
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Don't bother using mag primers your group looks good. I would be happy to leave it right there.


Straight Shooting

Budweiser2
 
Hehe, good advice here, funny, but very true. Switching primers will either increase or decrease your groups. The only way to find out would be to try it. Unless moose are super tiny in Ontario, it won't matter a lick, if you shoot .6moa, or .5moa. I'd say that you have your moose load, times are good :) With groups such as those, as far as you are comfortable shooting, a moose should go down.
 
You don't need magnum primers just because of the name of the cartridge. Magnum primers burn a bit hotter for a bit longer than a standard primer. They are for lighting hard to ignite powders and cold weather shooting.
As mentioned, if you change any one component, you need to work the load up again. Mind you, I'd just sight in with the H4350 load and practice shooting, off hand, at a 9" pie plate at 100 yards. Check your sights just before you go hunting. The colder weather might open the groups up a tick. Not enough to worry about though. Bullwinkle is a big SOB.
 
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