Powder for 300 Win Mag?

AKolomiets · May 16, 2018, 12:40 PM

Which powders do the 300WM loaders out there use? Whats your accurate go-to? I’ll be loading my first batches in this caliber and looking for a good starting point for bullets in the ~200gn range

T. O'Heir · May 16, 2018, 03:29 PM

It's usually best to start with whatever powder was used for the accuracy load given in your manual. Not all manuals have that though. Lyman's does.
Know a guy who shot DCRA(our long range target shooting organization. Similar but not the same as the NRA) 1,000 yard Sniper with a custom built .300 Mag. No ideas what powder, but he used 190 grain match bullets. No hunting involved though.
H4831sc keeps coming up on other forums.

Dufus · May 16, 2018, 03:45 PM

H4831SC is always good in the 300 WM. Also RL26 is good and temp stabilized. Matter fact, both of these two are.

Some of the newer powders are supposedly good, but I have no experience with them.

Retumbo and H1000 are also good choices.

sako2 · May 16, 2018, 03:48 PM

I'm currently using rl23 for a 190gn accubound. was using imr7828ssc with a 180gn speer. Take a look at rl26. Both rl23 and rl26 have decopper fouling additive and temperature stabilizer. Developed the 190gn load in 30 degree weather and chronoed at 2917 and chroned 2917 in 80 degree weather.

**Unclenick** · May 16, 2018, 03:49 PM

If you are new to reloading, I'll point out that case capacity varies more among different brands of .300 Win Mag cases than any other, so you want to use the same brand of brass your load data uses if you can. Broadly, Remington and TulAmmo have the lowest capacity at about 88 grains of water. Norma has the highest, at about 95.5 grains capacity. It amounts to almost 5 grains difference in charge weight to reach the same pressure. Winchester is about 93.5 grains case water overflow capacity, IIRC, so about 3.5 grains more powder than Remington.

old roper · May 16, 2018, 06:13 PM

Alliant expanded their site for 300mag and added bullets/powder

http://www.alliantpowder.com/reloade...aspx?gtypeid=2

I didn't shoot 200gr in the 300mag used 180gr Partition with H-4831SC good elk bullets and load out of Nosler manual.

AKolomiets · May 17, 2018, 06:31 PM

Thanks guys. I picked up some H4381SC. I plan to start playing with the load around the 67 grains recommended by Hogdgon. Anyone out there have a good load set up with the Berger 210 VLD using H4381SC or Hybrid 100V?

old roper · May 17, 2018, 08:04 PM

AKolomiets, You should ask Nick he's got all the case capacity and that 210gr Berger is almost 1 1/2 long" and you can have compress load. He might have load for you.

Stats Shooter · May 17, 2018, 09:10 PM

I have tried just about every single powder in .300wm with 150 gr bullets up to 225 gr which I use for my F-Open. 300wm.

H1000 has by far the most consistent velocities for heavy bullets. Extreme spreads in the single digits. It's also very temp stable. Retumbo is too slow burning, can't get enough in the case and performance suffers. H4831 is a bit too hot IMHO. it will work fine but wasn't as consistent. RL 26 is decent but I didn't get the consistency I found with H1000 .

IIRC Norma brass held 95.5 gr water and Remington 88 gr. Federal was around 92 gr and win 94. This means the books will understate pressure in Remington brass and overstate it in Norma. Once fired brass may grow from datum to casehead by as much as 0.02" or approx 1% in volume base roughly on my observations.....which could require an additional 1/2 gr to achieve the same velocity with New vs 1x fired. I only size it back 0.002" but I do FL size.

I have 3 different . 300wm rifles and have helped develop loads for several others.

The Hornady eld-m I use is 1.63" long. but I seat it 0.38" beyond SAAMI (3.72" vs 3.34") however the barrel in my f-open rifle is throated for it. In my model 70 .300wm I switched from the 200 gr nosler AB to the partition of the same weight to give more case capacity near SAAMI OAL as I could not exceed 3.40 due to mag restrictions. If you are not able to seat long due to mag restrictions, I would stay with a bullet that doesn't exceed 1.4".....unless you have a big chamber AND use Norma brass while fire forming before final load development.

Watch run out when seating bullets, the short neck of the .300 wm coupled with long bullets makes a good seating die critical.

Roadkill2228 · May 19, 2018, 05:30 PM

The new enduron powders show great promise. 7977 and 8133 in particular. I like a full case of slow powder. For 200+ Weight bullets, 7828, rl22, 25, 23, 26, h1000, and such. Large cases like this do best when filled to capacity or close to it

Roadkill2228 · May 19, 2018, 05:33 PM

I’m planning on running 208 eld m bullets in my savage 111 long range hunter .300 win mag with imr 7977 as my first experiment (also planning on trying out h b n coating bullets)

May 16, 2018, 12:40 PM	#1
AKolomiets Member Join Date: May 13, 2018 Posts: 23	Powder for 300 Win Mag? Which powders do the 300WM loaders out there use? Whats your accurate go-to? I’ll be loading my first batches in this caliber and looking for a good starting point for bullets in the ~200gn range

May 16, 2018, 03:29 PM	#2
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	It's usually best to start with whatever powder was used for the accuracy load given in your manual. Not all manuals have that though. Lyman's does. Know a guy who shot DCRA(our long range target shooting organization. Similar but not the same as the NRA) 1,000 yard Sniper with a custom built .300 Mag. No ideas what powder, but he used 190 grain match bullets. No hunting involved though. H4831sc keeps coming up on other forums. __________________ Spelling and grammar count!

May 16, 2018, 03:49 PM	#5
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	If you are new to reloading, I'll point out that case capacity varies more among different brands of .300 Win Mag cases than any other, so you want to use the same brand of brass your load data uses if you can. Broadly, Remington and TulAmmo have the lowest capacity at about 88 grains of water. Norma has the highest, at about 95.5 grains capacity. It amounts to almost 5 grains difference in charge weight to reach the same pressure. Winchester is about 93.5 grains case water overflow capacity, IIRC, so about 3.5 grains more powder than Remington. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

May 16, 2018, 06:13 PM	#6
old roper Senior Member Join Date: June 11, 2007 Posts: 2,155	Alliant expanded their site for 300mag and added bullets/powder http://www.alliantpowder.com/reloade...aspx?gtypeid=2 I didn't shoot 200gr in the 300mag used 180gr Partition with H-4831SC good elk bullets and load out of Nosler manual. __________________ Semper Fi Vietnam 1965 VFW Life member NRA Life Member

May 17, 2018, 08:04 PM	#8
old roper Senior Member Join Date: June 11, 2007 Posts: 2,155	AKolomiets, You should ask Nick he's got all the case capacity and that 210gr Berger is almost 1 1/2 long" and you can have compress load. He might have load for you. __________________ Semper Fi Vietnam 1965 VFW Life member NRA Life Member

May 16, 2018, 03:45 PM	#3
Dufus Senior Member Join Date: December 10, 2014 Posts: 1,965	H4831SC is always good in the 300 WM. Also RL26 is good and temp stabilized. Matter fact, both of these two are. Some of the newer powders are supposedly good, but I have no experience with them. Retumbo and H1000 are also good choices.

May 16, 2018, 03:48 PM	#4
sako2 Senior Member Join Date: April 12, 2009 Posts: 741	I'm currently using rl23 for a 190gn accubound. was using imr7828ssc with a 180gn speer. Take a look at rl26. Both rl23 and rl26 have decopper fouling additive and temperature stabilizer. Developed the 190gn load in 30 degree weather and chronoed at 2917 and chroned 2917 in 80 degree weather.

May 17, 2018, 06:31 PM	#7
AKolomiets Member Join Date: May 13, 2018 Posts: 23	Thanks guys. I picked up some H4381SC. I plan to start playing with the load around the 67 grains recommended by Hogdgon. Anyone out there have a good load set up with the Berger 210 VLD using H4381SC or Hybrid 100V?

May 17, 2018, 09:10 PM	#9
Stats Shooter Senior Member Join Date: August 26, 2016 Location: North Dakota Posts: 1,636	I have tried just about every single powder in .300wm with 150 gr bullets up to 225 gr which I use for my F-Open. 300wm. H1000 has by far the most consistent velocities for heavy bullets. Extreme spreads in the single digits. It's also very temp stable. Retumbo is too slow burning, can't get enough in the case and performance suffers. H4831 is a bit too hot IMHO. it will work fine but wasn't as consistent. RL 26 is decent but I didn't get the consistency I found with H1000 . IIRC Norma brass held 95.5 gr water and Remington 88 gr. Federal was around 92 gr and win 94. This means the books will understate pressure in Remington brass and overstate it in Norma. Once fired brass may grow from datum to casehead by as much as 0.02" or approx 1% in volume base roughly on my observations.....which could require an additional 1/2 gr to achieve the same velocity with New vs 1x fired. I only size it back 0.002" but I do FL size. I have 3 different . 300wm rifles and have helped develop loads for several others. The Hornady eld-m I use is 1.63" long. but I seat it 0.38" beyond SAAMI (3.72" vs 3.34") however the barrel in my f-open rifle is throated for it. In my model 70 .300wm I switched from the 200 gr nosler AB to the partition of the same weight to give more case capacity near SAAMI OAL as I could not exceed 3.40 due to mag restrictions. If you are not able to seat long due to mag restrictions, I would stay with a bullet that doesn't exceed 1.4".....unless you have a big chamber AND use Norma brass while fire forming before final load development. Watch run out when seating bullets, the short neck of the .300 wm coupled with long bullets makes a good seating die critical. Last edited by Stats Shooter; May 17, 2018 at 09:22 PM.

May 19, 2018, 05:30 PM	#10
Roadkill2228 Senior Member Join Date: March 8, 2014 Location: Nipawin, Saskatchewan Posts: 311	The new enduron powders show great promise. 7977 and 8133 in particular. I like a full case of slow powder. For 200+ Weight bullets, 7828, rl22, 25, 23, 26, h1000, and such. Large cases like this do best when filled to capacity or close to it

May 19, 2018, 05:33 PM	#11
Roadkill2228 Senior Member Join Date: March 8, 2014 Location: Nipawin, Saskatchewan Posts: 311	I’m planning on running 208 eld m bullets in my savage 111 long range hunter .300 win mag with imr 7977 as my first experiment (also planning on trying out h b n coating bullets)