Home Forums Reloading Big Game Rifles .300wsm reloading

How many of you guys neck size for the .300wsm, have you had any problems doing this? Also what are your thought of using a standard rifle primer with RL15, of for any .300wsm load for that matter?

Do you mean neck size only?

If so, you may have a problem when trying to feed the rounds going from the magazine to the chamber. The casing shoulder might hang up due to its 35 degree angle.

For my 300 WSM, I always full size my brass. Doing so will insure very good feeding and as such I`ve never had a problem with feeding while maintaining very good accuracy.

I have always used the large rifle mag primers. However, you can use the large rifle primers where it is listed. In my V Edition Sierra, the WLRM primer is the only listed primer for the 300 WSM. In my 49th Edition Lyman manual, only the WLRM primer is listed (WLR primer for cast bullets). In my `08 Hodgdon manual, only the WLRM primer is listed. And yet again, in the 6th Edition VihtaVouri manual, only the large rifle mag primer is listed.

So imo, its a good idea to stick with the type of primer that is listed in the majority of 300 WSM data.

I would have no objection to using the large rifle primers in loadings WHERE it is listed to do so.

Interestingly, in my `08 Hodgdon manual in an article by Layne Simpson entitled "How to Build Trouble Free Handloads," I read the following on pg 47; quote,,,,

"With few exceptions, I have never been able to detect any difference in performance of loads using standard and magnum primers when loading various stick powders in standard-size cartridges and firing them in ambient temperatures ranging from cool to hot. There are three occasions when I use magnum primers such as Remington 9 1/2M, Fed 215, CCI250, and Winchester WLRM exclusively. One is when reloading magnum cartridges of all calibers, and I believe this to be especially important when working with those with huge appetites of powder.

"I also use a magnum primer when loading ball or spherical powder in any cartridge that requires charges heavier than 40 grains. The heavy deterrent coating on some of those powders requires the prolonged heat delivered by a magnum primer for uniform ignition, and while some spherical propellants seem easier to ignite than others, I prefer to keep life simple by using magnum primers with all of them."

"Regardless of the type of powder, I use a magnum primer any time the temperature during a hunt is likely to drop lower than 32 degrees, simply because the lower the temperature, the more difficult it is for powder to ignite uniformly.",,,,,Unquote

If I were you, regardless of the powder or the charge (UNLESS OTHERWISE LISTED), stick with the large rifle magnum primers for the 300 WSM.

Neck sizing seldom works in any WSM because of the case shape. I have to set my dies so the press actually "cams over" to get easy feeding.

I neck size for my 300, 325 and 338 WSM's. Same with 338 Jamison which is almost the same. Never a problem, neck size four times, anneal and set back the shoulder .001" and start again. Neck sizing isn't going to affect cartridge going into chamber. If it hangs with neck sizing it will hang full sizing. WSM's don't need to be treated any differently than any other cartridge.

Exactly and you don't need mag primers either.

I shoot nothing but CCI BR2s in mine with RE17, H4350, and RE25. Most loads with all three powders are less the 3" at 300 using 185gr Bergers. RE17 is giving me the best groups and vel. I am getting right at 3000fps and 1.5-2" groups at 300 in a factory 26" Rem tube.

And I can't tell 10x fired WW cases from 1x. Trimmed them at 8x.

Thats cuz you're shooting that hammer forged foreign junk with a tight chamber....




Or did you trade that one to Swampman for a 700 too??