[Dean44]

I am looking for the best powder for tried and true accuracy with 180 grain bullets and 300 WSM.

The rifle is a new Winchester Model 70 FW. Factory 180 Grain Winchester ammo groups less than 1" at 100 yards - consistantly. I then loaded some 180 grain ballistic tips with Magpro and groups opened to 2 inches.

I though it better to ask for your experience rather than buy a bunch of different powders at $25 a pound.

Thanks for your help!!

Dean44

 

[TMan]

I think you might find that another brand of bullet, or a slight change in charge weight would fix your accuracy problem. So be sure to try that first. If I were making a bet, and had to get it on the first pass, I'd pull out a can of H/IMR-4831. Not anything to do with the WSM specifically, but in 40 years of filling all sorts of overbore cases, the 4831's have never been poor in the accuracy department, and often as not, they are tops.

For the most part, I'd try a different bullet. For whatever reason, some rifles just don't like some bullets. I have a tack driver Whelen that shoots, Hornady, Speer, and Sierra bullets, over three different powders, to under an inch. I could not find a single powder, primer combination that would shoot Nosler Partitions into less than 2.5-3". My .243 MKII doesn't like Speer bullets, but shoots Sierra and Hornady bullets of the same weight just fine.

Why? I haven't a clue.

 

[2Bits]

I too will tell you that H-4831 and IMR-4831 have been taking care of the .300 caliber rifles for many decades now. However, you can give Viht N550 a try, according to Noslers new manual, they favor that at 61 grains MAX for a velocity of 2976fps. Please do start at least 5 grains LOWER for starting out ok.

 

[FFguide]

300 WSM and 180 gr. bullet

Dean 44....I am new to this forum, but not new to reloading or hunting....still a lot to learn. This is what I use for my Winchester Model 70 in 300 WSM...H4350 with a Speer 180 Grand Slam, 3/4" groups @ 100yards, deadly on elk and deer. Also this year I have been experimenting with Hornady 180 Gr. SST loaded with H4350. Very accurate. Again 3/4" groups. I have not harvested any wildlife yet because I am impressed with the terminial performance of the Grand Slam...Additionally I load the Grand Slam for my wife in her Model 70 30-06.....Hope this helps.

 

[old roper]

I am looking for the best powder for tried and true accuracy with 180 grain bullets and 300 WSM.

The rifle is a new Winchester Model 70 FW. Factory 180 Grain Winchester ammo groups less than 1" at 100 yards - consistantly. I then loaded some 180 grain ballistic tips with Magpro and groups opened to 2 inches.

I though it better to ask for your experience rather than buy a bunch of different powders at $25 a pound.

Thanks for your help!!

Dean44

Lots of good powder for the 300WSM and I cann't say much for Mag-Pro and afew other powders that I've tried. In the 270WSM and 300WSM I'm changing over to R-17 and I've had good luck with H-4350,IMR-4007ssc, N-550/165 was so-so.

I think it was around 2002 when I first started loading for the 300WSM and I think must of picked up about 10 different powders and then I added afew over the years.

I think the powders out of Hodgdon manual are alittle better than whats in the Nolser manual as most of their data is out of a custom barrel 26" long which most 300WSM don't have.

I wish I could tell you for certain R-17 work in your rifle you might want to try some other site and post your question might be surprise what you find.

Well good luck

 

[William A. Reed]

Found this round to be a bit finicky in the M70. Found 180 gr. Sierra spitzer and a heavy charge of H4831sc using WW brass and magnum primers gives excellent accuracy. Have not chronographed to date as this is a very recent undertaking.