Primers for 300 WSM

[Franco]

I am a relatively experienced reloader but just starting to load 300 WSM and see some conflict in the manuals relative to primers. My Nosler guide lists WLRM as the primer used for all of the listed loads but Speer says to use CCI 200 (Large Rifle) unless the powder indicates a mag primer, in which case you use CCI 250 (Large Rifle Magnum). Very few of the powders listed in Speer indicate use of a magnum primer and most of the powders listed in both guides are pretty much the same. I normally use CCI primers and I will be loading 180 gr Nosler Accubond w/ IMR 4831. Any suggestions as to primers? Thanks in advance.

 

[JimKirk]

I think that you'll find that either will work well in your cartridge... I don't reload for a 300 WSM, but I do for the 270 WSM. I've used both with good results and found very little difference between them. If I was hunting in cold weather I would use magnum primers for sure, also if you are using any ball type powders. With IMR 4831 either will work. If you are at a maximum load and swap primers(standard to magnum), I would reduce(slightly) the charge and work my back up. If you go from magnum to standard, I would not worry about it.

Jimmy K

 

[loadedround]

Franco:
The easy answer to your question is to load say 20 cartridges, 10 each with each primer and shoot for group while watching for any pressure signs. Let your rifle make the decision for you. Remember all rifles will shoot differently.

 

[mhat]

I load the 300wsm, I use only large magnum primers. That's from the 110 gr. varmit load to my 180 gr. hunting load, with very good results across the board.

 

[NCsmitty]

www.hodgdon.com lists Win WLRM for all their loads in the 300 WSM.

I think that you have gotten good info from the other posters, and my take is to use magnum primers with ball powder, and standard primers in extruded powder loads, pretty much like JimKirk mentioned.

That said, if you have a supply of magnum primers, then using a start load of IMR4831 with magnum primers and working up from there, should be fine.

You can also split the workup like loadedround suggested, and determine which works best for you.
You have lots of options, and you and your rifle can make the final decision.



NCsmitty

 

[FROGO207]

I load my 300 WSM using magnum primers as I think that most of my shooting will be when it is cold and want reliable ignition every time. I have been doing this for three years or so now and am happy with the results so far.

 

[hoghunting]

My best accuracy and performance in the 300 WSM come from using WLRM and RL-19.

 

[Franco]

Thanks all. This is helpful. I think that I'll buy some WLRM primers rather than CCI 250s so that I'm consistent with your experiences and with 2 out of 3 of my load manuals. I wasn't so worried about accuracy relative to primers but more about excessive pressures. However, I'm going to load in the lower/mid range of the load books so I should be ok in that regard. Very interesting comment about temperature too -- I hadn't thought about that and most of my hunting is in Nov/Dec (i.e. friggin cold out). Thanks again.

 

[JimKirk]

Has anyone else noticed that Winchester primers have softer cups than other brands? I mean ... that a normally safe load will have somewhat "more flattened" (not flat) primers with Winchester. I even noticed that factory Winchester ammo will have a "more flattened" look than say Remington or some of the others.

I like Winchester primers and have had good results with them!

Jimmy K