large rifle primers for magnum

[Come and take it.]

I bought a .300 Winchester magnum and have all the components I need except for the magnum primers of which I can find none anywhere.

I do however have a decent supply of both large rifle and large rifle benchrest primers.

Can I use large rifle primers?

My powders are win supreme 780, imr4064, imr4350.

 

[Ifishsum]

Use the standard large rifle primers. It's the powder itself that generally dictates the primer type, not being a magnum cartridge. Generally speaking, magnum primers are often suggested for ball type powder because it can be harder to ignite in cold temps. It's not a necessity though, and for the stick powders like 4064 and 4350 there is probably no benefit at all to using magnum primers.

 

[kraigwy]

My 300 WM is a target rifle so I use match primers in it, HOWEVER, I use 4064 in my 375 H&H with standard large rifle primers.

Don't know why they shouldn't work in a 300 WM using 4064.

 

[jmr40]

You can use LR primers for now with no dangerous side effects. I'd start with what you have, but still be on the lookout for magnum primers. When you do get some you'll need to adjust your loads. You'll probably see a little more speed with the same powder charges and maybe a little better accuracy.

Accuracy may, or may not be optimum, but until you get some magnum primers to compare you won't know. It is true that powder type plays a part, but so does case capacity. The more powder in the case, the greater the need for magnum primers. Most reloaders suggest magnum primers with any charge of over 60 gr of powder, even less with ball powders, or in cold weather.

A lot of shooters report better accuracy with magnum primers in standard loads such as 308. I've tried magnum primers with both 308 and 30-06. If there is any difference I'm not good enough to notice it on my targets, but it didn't hurt either.

 

[Come and take it.]

I have a couple of friends that might have some so I might not have to compromise just yet. But glad to know I can use large rifle with the stick powder if I need to.

The 780 is a rounded stick powder so it is a lot like ball. I will probably need to use magnum primers with that I suppose.

 

[10 Spot Terminator]

The case in point for the magnum primers is primarily directed at performance in colder weather using powders that tend to be somewhat temperature sensitive where a hotter spark can tend to benefit. Load data for such calibres as the 300 Winny are directed at hunting rifle performance and not so much as target rifles. Using powders such as those listed by Hodgdon as EXTREME powders reduce the temperature syndrome and would be more user friendly with standard primers. Load adjustments will need to be made in most cases to compensate but will work fine .

 

[CharlieDeltaJuliet]

I use H1000 with my 300WM and 215 match magnum primers, but I totally get the non magnum with powders like 4064.

 

[Mike / Tx]

Usually I will try out a magnum primer when my loads get into the 70 - 75 grain per charge weights. Sometimes they work better sometimes not. Neither however, have ever had an issue lighting off the medium to slower powders I normally use. If I go with the slowest, like H-100 or a similar burn rate I will usually use the mags

With ball types in the past I have gone by the rule to use them as they were usually recommended. Even with some of the loading manuals listing mag primers in loads, I have found better accuracy and consistency with standards over mags with most loads. I do however use mostly Winchester, and CCI-BR2's. If using the magnums I use the Fed 215 GM's exclusively.

 

[reynolds357]

LR will work fine with all three. Hodgdon actually calls for LR primers for Supreme 780 in the .300 Win mag.