300 Winchester Mag / Reloader 19 W/ Mag Primers

Danny,

Welcome to the forum. I have a question for you, though. Why would you not use a magnum primer with RL19 in a 300 WM? With the longer powder column of the cartridge and the somewhat greater volume, the cartridge benefits from the primer with higher brisance, which indicates magnum primers. Especially if one anticipates hunting in cooler weather, the magnum primer would be strongly advised to ensure full ignition of the charge.
 
I always use magnum primers in a .300 Win Mag. I use either CCI or Federal 215 primers on all loads for this cartridge. My best 300WM elk load has a hat full of 4831, fired by a 215, and pushing a Partition 180 out of a 26" Douglas barrel.
 
Thanks for your replys to this topic guys. It is very much appreciated.

DrMike, I don't have any problems in using magnum primers for the 300 Winchester Magnum, or even other calibers with large columns. I was getting ready to reload a batch of brass using Nosler 180 grain bullets, and I wanted to make sure it was safe using magnum primers with Reloader 19 powder.

Titleist. It sounds like you've definately got the optimum load for this cartridge, and I'm going to give this load a try too. Regarding the powder, are you suggesting H4831 or the IMR 4831? I am assuming these have very similar burning rates? However, Lee Loader Co. recommends that you don't use "Federal" brand primers, as they say those primers can be a big safety concern. Unfortunately, they don't go into any details very much abaout "why" this is?
 
The Fereral 215 is a little bit hotter than the CCI 250. In this case the 215 gave a smaller range of velocity difference than the 250 when fired over the chronograph. In some loads the 250 might be the winner, but my barrel likes this particular combo best. The factory tube I had on this rifle (before the Douglas) was 24" and had a slight preference for the CCI 250 primer. All barrels are different. I don't switch primers on a load unless I back off of the powder charge and work back up. If you had a max charge fired by a 250, you might get too much pressure if you fired the same load with a 215. There is nothing wrong with either the CCI or the Federal primers, but they are slightly different.

The same goes with powder. The burn rate of H 4831 is slightly slower than IMR 4831.

I never tell anyone on public forums what the max charge is on my loads, as their max load may be different. This load for my .300 WM uses IMR 4831. My rifle got good velocity with RL 19 also, but the velocity deviation was larger and the groups were also a bit larger than the IMR 4831 loads. Again, all barrels are different.
 
The 215 M is the only primer I use in all my magnums. That is all I run and get pretty good results. They are a hot primer as opposed to the CCI stuff which I only use for pistol.
 
Danny,

In general, you can use a magnum primer on any rifle load. It will increase pressure, which would mean that you want to drop back and work up the load to avoid pressure problems. It is a good rule to use the primer recommended in the recipe provided by the manufacturers of propellants and bullets. They will have conducted the appropriate pressure tests. I use a lot of magnum primers from each of the major manufacturers (R9.5M, WLRM, CCI250 and F215); any will work in your 300 WM. Just be certain to work up your load from a safe minimum.
 
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