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I am shooting a 26� 1:10 twist 300 Win Mag. I am finding that with the Nosler 200 Partition and the Sierra 220 Matchking that I am getting best accuracy with loads that are difficult to extract. Bolt lift does not seem overly difficult. Primer pockets are holding new primers just fine. No ejector blade marks are evident on the case. But I guess that the loads are too hot. I have tried RL25 and H1000. I have never tried Ramshot Magnum (used to be called BigBoy). Would this be a good alternative? Perhaps RL22 or H4831 would be good to try also but I figured slower powders would be better with these heavier bullets. Any thoughts? Thanks, Rufous.

The data that I have on the .300 Winchester Magnum indicate that with the 220-grain Sierra seated to an OAL of 3.34 inches, for pressures not to exceed 50,000 lb/sq in. and net case fill not to exceed 100%, these five powders are most productive -- producing muzzle velocities about 2,700 ft/sec:
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<br>1. Reloder 25 -- 100% case fill
<br>2. Ramshot Magnum -- 94% fill
<br>3. Norma MRP -- 91% fill
<br>4. IMR-7828 -- 93% fill
<br>5. H-1000 -- 95% fill
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<br>Any increase in charge weights (% case fill) will increase pressures a good bit higher than my personal maximum but won't increase velocities enough to be worth the risk or the wear and tear on the case and bore.

Mr. Howell, thanks for your reply. I am confused about a couple things. First of all I thought that most belted magnums, including the 300 Winchester Magnum, had a SAAMI max pressure of about 62000 psi. You mentioned 50000 psi. Did you mean 50000 cup? Secondly you say that at 3.34" and 100% case fill with RL25 I would get about 2700 fps and the same velocity with 95% case fill on H1000. How is % case fill determined? I cannot see how one could fill the case 100% full and still seat a bullet, especially to 3.34". I am seating to 3.570" with the 220 Sierra Matchking. I am also finding that I need to use more H1000 to get the same velocities as RL25. For instance 76.5 grains of H1000 is giving me the same velocities as 74.0 grains of RL25. Hoping you can clarify some of this for me, Rufous.

Yes, he means 50,00 psi, not CUP. If you read his prudent pressure for rifles thread, you would see why. It is Ken's belief that the extra 10,000 psi isn't worth the velocity it gains because it puts too much wear and tear on the bore of the rifle. Ken explains it well in that thread.

The purpose of my original post was to see if others had used Ramshot Magnum successfully in this case and with this bullet weight. As I stated I am finding that I am getting best accuracy at the higher charges. I would be happy to load to lower pressures and velocities (say down to 2750 fps instead of 2830) if I got better accuracy. I was hoping that maybe a different powder would give me that. I guess I can only try and see. Rufous.

"How is % case fill determined? I cannot see how one could fill the case 100% full and still seat a bullet, especially to 3.34"."
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<br>"100% case fill" fills ALL the space between the web of the case (where the primer vent is) and the base of the seated bullet. It doesn't mean full to the mouth.
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<br>Yes, I mean 50,000 lb/sq in., not 50,000 c u p.
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<br>There are three, not just two, crucial pressures that careful, responsible handloaders need to keep in mind always -- and to some degree be familiar with:
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<br>1. proof pressure -- too hot for repeated use -- meant to proof (test) rifle's strength -- to be fired in one rifle only ONCE
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<br>2. maximum pressure -- lower than proof pressure -- the most that can be SAFELY fired repeatedly in one rifle
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<br>3. optimum pressure -- the best practical pressure -- safer than maximum pressure -- also less strenuous on barrel and shooter -- usually produces best accuracy
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<br>Optimum pressure gives the best results at the least risk (of these three levels of pressure). In cartridges and rifles SAAMI-rated at 60,000 to 65,000 lb/sq in., the optimum pressure is typically around 50,000 lb/sq in.
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<br>In loading to what the classical ideas of "pressure signs" imply is around SAAMI maximum, handloaders typically develop pet loads that many pressure tests have shown to be 70,000 lb/sq in. (proof level) and higher.
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<br>Also, many of us have found that whenever we pass a good load on to others, somebody in the crowd assumes that more's better and loads more, often with a severe learning experience as one memorable result. So I don't usually list maximum loads -- somebody's sure to hoist 'em beyond proof and blame me for his frozen or burst rifle.

Ken, I am still wondering if you have any suggestions as to what I could do. I do not care to run at too high of pressures but I do want the best accuracy I can get. It seems to come at max loads. In your experience would switching powders possibly enable me to get best accuracy at lower pressures? So far with two bullets and two powders I am getting best accuracy at pressures that are causing difficult extraction. I think that the pressures are high but I also think that perhaps the chamber needs some more polishing just in front of the belt. Rufous.