Looking for the best load for 300 win mag


December 30, 2012, 11:28 PM
Starting to reload the 300 win mag in a Remington 700. What powder would be best to start with. I reload the small caliber rifles, 223 and 308, but not the magnum calibers. Looking to load the 168 Sierra Match King. Any information would be greatly appreciated.

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December 30, 2012, 11:59 PM
RL22 with about 75-76 gr. would be a good place to start.

December 31, 2012, 10:47 AM
As per Sierra....

Accuracy load: IMR4350 at 72.0gr. for 3,100 fps
Hunting load: H-4831 at 81.5gr. for 3,200 fps Max. Load

No offense.... the 168gr works very well in the .308.... but I would move up in bullet weight for the 300WM.... 190gr at least, or even the 208A-Max, because of their higher BC

December 31, 2012, 11:13 AM
For paper punching I agree with bfoosh. But my 300wm A-bolt just likes 165gr. the best. I shot a 1 1/2" group today at 300yds with 165 accubonds.

January 1, 2013, 11:02 AM
I have a 700 that loves 4350 with 150gr hornady's.it will shoot 1" all day,it has a vias muzzle brake on it.

January 25, 2013, 07:35 PM
I prefer R22, and I only use 180 grain bullets.

January 26, 2013, 01:21 AM
My standard load for the 300 Winnie is 76 grains IMR-4831 and 150 Nosler Ballistic Tip. Extremely accurate in my S&W 1500. Never hunted Elk with it, if I did I would likely move up in bullet weight to the 165 or 180, which ever performed the best.

10 Spot Terminator
January 26, 2013, 08:29 AM
My Browning A-Bolt likes 73.0 grs. of IMR 4350 using the Barnes 168 gr. TSX and can cover a 5 shot group at 200 yds. with a quarter. Due to the Barnes being a grooved bullet , pressure is slightly lower than than using most other bullets so those you have should pretty much be spot on with the 72.0 gr. accuracy load posted earlier from Sierras' manual.

January 26, 2013, 08:50 AM
If you have any H4895 on hand, try some reduced 300wm loads with it. Good paper puncher with little recoil.

January 26, 2013, 12:19 PM
Yup, after you're done playing with 168 grain bullets, step up through 180, 200, and 220 grain bullets to see how your rifle behaves.

My old Savage 112 liked to get fed 220 grain bullets late-in-life, after throat erosion set it, it became a fine shooting old beast right up until I couldn't tolerate the fouling anymore. :)

The new barrel I have on it is still being experimented with, but 220 grain loads weren't anything to write home about, so now I'm stepping down to 180-190 grain bullets for comparison.

If you load the longer, heavier bullets, would be worthwhile to find out exactly where your "lands" are, so you can load those bullets out as long as you can.

I've found that having the base of the bullet protrude too far past the neck, in to the case, hurts accuracy.

One of the reasons I suspect my new barrel isn't liking 220 grain bullets is I can't load them as long, overall, as with my previous barrel. Maximum length I can obtain with them, still leaves quite a bit of the base of the bullet shoved past the neck and in to the cartridge.

180 grain should mate the two together rather well on my rifle, front .002 off the lands, while the rear taper (boat tail segment) starting precisely where the neck support ends. The configuration of that weight projectile on my rifle, is about as "ideal", as ideal gets.

January 27, 2013, 07:06 AM
Have you shot any of the Berger Bullets, say 185 to 210?
What powder do you like for the heavier loads?
Is 4831 good for anything 300 WM?

January 27, 2013, 11:17 AM
Yes, I just shot some Berger VLD 210's and have 5 more test loads worked up with them with H4831SC. They're pretty solid shooters, my first batch of testing was with them and I'm revisiting H4831SC/210gr VLD's for more experiments with seating depth!

I also have a set of loads worked up in 220 gr Sierra matchking w/ H4831SC .

But for reasons mentioned before, I think I can squeeze some more accuracy out with a slightly shorter bullet. I have a box of 185 gr VLD sitting in a box that just showed up from Midway this week. Expensive buggers!

I also bought a box of 185gr Lapua FMJBT for comparison.

I'm trying to find a projectile that'll sit up close to the lands and has a rear taper that starts where the shoulder/neck joint is. That way I'm not stuffing a bullet way down in to the casing. Prior experience with this and other calibers showed me that having the base of the bullet sticking way down in the casing is detrimental to accuracy.

My working theory is having the base of the bullet shoved back too far, causes the base of the bullet to either slightly deform prior to movement, or skews it to the side prior to movement, causing run-out. (Or both). Unfortunately I haven't set up a capture test that will let me measure and examine the fired bullets to get a better read on it, everything I hit makes the bullet shred. :)

January 27, 2013, 11:25 AM
Other powders I've used recently are H4350 w/ 220 gr Sierra, H1000 w/ 220 gr Sierra.

My previous best load on the old barrel was with H4831SC w/ 220gr Sierra projectiles, which is why I started there this time. :)

The lands on my barrel start at 2.845" (on a bullet seated overlong and died prior to chambering, measured from rear of casing to first rifling markings).

Important to measure this early on, so you have an idea of throat erosion over the life of your barrel. 300 Win Mag isn't a pop-gun, you'll be fortunate to get 1500-2000 shots out of it.

As throat erosion slowly steals you of nice crisp lands, your optimal cartridge OAL length will gradually lengthen, you'll need to keep up with it to retain accuracy.

As my throat erosion went on in the old barrel, I kept my CAOL growing to match, and stumbled on a sweet spot with those 220 gr sierras WAY the hell too long. It confused me for awhile, why a rifle that'd historically shot .75 MOA suddenly was shooting .3 MOA.

Needless to say it was kind of exciting and I shot the heck out of the thing for awhile. :)

I struggled with finding the answer until one day I just stared at a round I'd just finished loading on the bench. I took an unseated projectile and put it next to a loaded round, comparing where the tip of the bullet was, and found that the boattail of the seated 220 gr bullets were precisely at the neck/shoulder junction on the casing. I mean, exactly.

I figured it's a phenomenon worth re-testing. :)

My lands are still intact on the new barrel, so I can't load 220 gr's long enough to line them up this way - they'd be jammed .2" in to the dang rifling if I tried. :)

So I'm going with a lighter bullet, to see if I can match it up better.

January 27, 2013, 06:10 PM
My 300 WM likes IMR 4350 with Berger 155gr. and 168gr. VLD's. Both have these have shot sub .5 MOA groups and have been very effective on both elk and Oryx. Tried R-22 and just wasn't getting the same accuracy but may be due to the lighter bullets. They are too short to get close to the lands and played with seating depth to get the best result. Good luck.

Lloyd Smale
January 28, 2013, 07:40 AM
my go to powder for 165s in the 300 win mag is re19.

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