Just got done shooting some 200 grain Barnes TSX in my Win 70 classic 26" barrel.

IMR 7828 71 grains 2766
72 grains 2790 (case is full)


Retumbo 75 gr 2861 (case is full)
80 gr 3006 (way over max in my rifle, brass flow but no sticky bolt) The bullet would not stay seated with this much powder but 84 grains is the highest max I found for a 200 grain bullet. So that is why I tried 80.


IMR 4350 65 grains 2681 2745
66 grains 2778 2767
67 grains 2843 2829 2808

The highest max I found for IMR 4350 is 69 grains for a 200 grain bullet so I will go up a couple more grains because I am not getting any pressure signs and there is just enough room.

69 grains is MAX load for IMR 4350 in all my load books. I would not go over that.

I had good luck with RL22 at 74 grains, produced 2950 fps and fairly accurate.

Most accurate was H4831SC at 71 grains, but kind of slow at 2770 fps.

Might be better to slow that bullet down, read

https://forums.accuratereloading.com/eve/forums/a/tpc/f/2511043/m/826101232


Without guns we are subjects, with guns we are citizens

Go with what Woods says. I have had best luck with those two powders. I would start with H4831. More long distance benchrest shooters using the 300 use H4831 than any other powder, and that is a fact (190 to 220 grain bullets).

I had tried 72 grains R22 in another 300 win mag that I had. I consider it a max load for that rifle and velocity was 2830 with a 200 X.

I like the 67 grains of IMR4350 at 2800 and will see what 69 grains will do.

I am wanting 2800 + without having to go to a hot load and IMR 4350 easily does that.


Before I can really go much higher in load developement I need to wait till the temp get a little higher preferably 50*+. That wont be for another month .

If you tried H4831 you would need to chrono them. I shot 200 grain accubonds out of my 300 WM and chronod them at 2890 FPS (VERY low SD and ES BTW) using 71 grains H4831. I had a 26" barrel. Also, I know guys suing H4831 with 220 grain bullets getting 2750 FPS out of a 26" barrel. Not trying to pull you one way or another, but H4831 has proven itself time and time again for me.

I have been thinking about trying H4831 but it seems like the difference between it and IMR 4350 would be minimal.

I have been very pleased with IMR 4350 and have it on hand. I found it to be very good in the 300 WSM and 375 Ultra also.

What might not be minimal between H4831 and IMR 4350 is the temperature sensitivity.

I just started using 70.5 grains of H4831 under a 200 grain partition. I tried heavier charges but accuracy suffered too much. I have a 25 inch barrel, but haven't chrono'd it yet. Not real worried though. This is my rifle for everything and I think a Hodgdon extreme powder and a 200 partition will take care of just about anything in NA

Miller, H4831 is more different than you may think. Accuracy with the heavier bullets can be tremendously different. You have an accurate bullet there, and it may do best with H4831. What kind of groups and standard deviation are you getting with the 4350? If it is low and your groups are good then you have accomplished what you're after. Just remember, I am seating clear out (I can seat to 3.56" out of my magazine) so your rifle may show higher pressuers for the same charge, but both my loads are still just under max in most books.

Ralphie, generally you can't go beyond 71 grains anyway and still keep good accuracy even when you seat clear out. 70.5 grains is about optimal for most rifles. this is a generalized statement, but danged if it hasn't worked in most every single case I have ever seen. Most 300 WMs just take to H4831 and heavier bullets. With my custom 300WM and 28" 1 in 11" twist Broughton barrel I can shoot under 0.3" with 200 grain matchkings and 71 grains H4831. I then use 73.5 grains H4831 with the 180 grain accubonds for the same accuracy for my hunting load.

Shilen30,

That is exactly what happened with my rifle. I can seat out to about 3.55 with my magazine box. It didn't matter. Even when I went to 71 grains from 70.5 accuracy went bad. When I built this rifle I was most interested in shooting 200 grainers and H4831 has been head and shoulders above IMR 7828, RL22, Ramshot Magnum, and IMR 4350.

I went to 66.5 gr of IMR4350. I have a 25" barrel and I don't want those 200 gr bullets to much over 2800 fps.

I can only seat my bullets to around 3.360 .

Might be only around three more weeks til I can shoot in warmer temps (50*f) to see if my loads are still under max.

I may have to give H4831 a try just because. Plus I would like to see if there is an accuracy difference. See which one has the best minute of moose accuracy.