I have a number of different powders, in differing quantities on my reloading bench. I just acquired a new Remington 700 CDL in .257 Weatherby and would like to get it to shoot the Swift bullets. If they don't work I will probably move to 110 gr. Accubonds. Out of the powders listed, which one would you start with...in hopes that it ended there?What would you start with?IMR 7828RL25RL22H1000IMR 4831IMR 4350RL19If that powder doesn't turn out, what would be your next choice?IMR 7828RL25RL22H1000IMR 4831IMR 4350RL19

IMR 7828 and 100 grain bullets shoot very fast and accurate in my custom 257 WBY. It is partial to ballistic tips.

The slowest powder you have listed is RL-25. It will probably do fine with only a 100 grain bullet, but you'll be better off with an even slower propellant if you jump to 110, and especially 120, grain bullets. IMR 7828 is the second slowest and would be the backup choice.

Powders like IMR 4350 and IMR 4831 are too fast for optimal performance in a .257 WBY. However, if you don't own a chronograph and don't care about pressure so long as the fired case can be extracted from the gun, you can get by just fine with such faster powders.

After 20 years and a dozen 257Wbys I load for RL22 has always been my favorite for 100 grains and less for velocity and accuracy. It is one of the few powders that always seems to work with .257 Sciroccos.

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The slowest powder you have listed is RL-25. It will probably do fine with only a 100 grain bullet, but you'll be better off with an even slower propellant if you jump to 110, and especially 120, grain bullets. IMR 7828 is the second slowest and would be the backup choice.

Powders like IMR 4350 and IMR 4831 are too fast for optimal performance in a .257 WBY. However, if you don't own a chronograph and don't care about pressure so long as the fired case can be extracted from the gun, you can get by just fine with such faster powders.

What Stonecreek said x 2.

I know this isn't the most current topic, but oh well.

My load with my 257 wby was based on R25. I had potential with H1000. I ended up using H1000 with the VLD, and.. Go figure, my 110 Accubond load is with R22. I think theory says that the R22 and R25 should be reversed, but thats where the accuracy is.

Side note, I have seen many people say 7828 is 'the' powder for this round, but I haven't seen a ton of potential. Granted, I haven't played with it too much.

I'm late too. My Accumark prefers IMR7828 with 110 and 120-grain bullets, giving higher velocity and better accuracy than RL25 or H870. Why some folks seem to believe that slower powders will always give higher velocities in this cartridge puzzles me. I guess they read it in some article in the slicks or on some guy's blog...

Slower isn't always faster, as a simple perusal of various loading manuals will demonstrate. For example, Hodgdon 117- and 120-grain data shows considerably higher velocities with IMR7828 than with H1000.

But for top accuracy, different barrel/action/bedding combinations may show different powder preferences. If accuracy is the goal, then an extra 50-75 fps is pretty meaningless.


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I shoot H1000 under a coated 115gr NBT for 3337fps. I might could run them faster but I have extremely low spreads and half-minute precision out to the 300yds I've tested the load.

My 257 Vanguard likes retumbo and rl-22 with 110-120 gr bullets

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