I had been looking for H-1000 powder for almost 4 months up here, but finally gave up. I stumbled into an 8 lb bottle of Retumbo, so bought it.
Speer is the only manual that lists Retumbo in .257 Wby (that I could find), so used their data as a basis for my loads.
I used:
new Hornady brass
Fed LR mag primers
Berger 115 VLD bullets
Retumbo powder 65.0 - 70.6 gr
C.O.A.L. was 3.350" (2.754" with collimator)
I started at 65.0 gr and went up 0.3 grains at a time. (ended up with 20 rounds loaded)
Test was fired at 200 meters
All brass was measured across the belts with my micrometer before and after firing. Cases were marked with a Sharpie and all cases were orientated the same way in the chamber
Maximum expansion at the belts was 0.0005" (yes, that's 3 zeros and a 5) average expansion was 0.0001". Some of the cases showed no change at all.
I measured 5 rounds of Weatherby factory ammo as well to see how much it expanded at the belt after firing. 100 grain Spire Point ammo ranged from 0.0015" - 0.0023" expansion. That's 3 to 5 times more case expansion than maximum expansion with my loads.
I hit a "sweet spot" at 69.4 - 70.0 grains. (3 shots in 3/4" at 200 m.) Speer max with 120 grain bullet is at 69.0 gr
I experienced absolutely no pressure signs at all, bolt opened easily (2 fingers), primers showed less flattening than the factory loads, and as I have stated, minimal or no expansion of the cases.
I would have chronographed the loads yesterday, but I was shooting in a steady drizzle. I'd like to see 3350 - 3400 fps. I'm going to be using the rifle this winter as my "Wolf Whacker". Where I live, there's no closed season and no bag limit on wolves.
I plan on getting out and continuing the ladder test with more powder in the case. My plan is to stop when I hit 0.0015" expansion, when I can't get any more powder in the case, or when I hit the desired velocity
Thoughts???..................Am I crazy??
ps: Test was fired using my Accumark rifle.
Speer is the only manual that lists Retumbo in .257 Wby (that I could find), so used their data as a basis for my loads.
I used:
new Hornady brass
Fed LR mag primers
Berger 115 VLD bullets
Retumbo powder 65.0 - 70.6 gr
C.O.A.L. was 3.350" (2.754" with collimator)
I started at 65.0 gr and went up 0.3 grains at a time. (ended up with 20 rounds loaded)
Test was fired at 200 meters
All brass was measured across the belts with my micrometer before and after firing. Cases were marked with a Sharpie and all cases were orientated the same way in the chamber
Maximum expansion at the belts was 0.0005" (yes, that's 3 zeros and a 5) average expansion was 0.0001". Some of the cases showed no change at all.
I measured 5 rounds of Weatherby factory ammo as well to see how much it expanded at the belt after firing. 100 grain Spire Point ammo ranged from 0.0015" - 0.0023" expansion. That's 3 to 5 times more case expansion than maximum expansion with my loads.
I hit a "sweet spot" at 69.4 - 70.0 grains. (3 shots in 3/4" at 200 m.) Speer max with 120 grain bullet is at 69.0 gr
I experienced absolutely no pressure signs at all, bolt opened easily (2 fingers), primers showed less flattening than the factory loads, and as I have stated, minimal or no expansion of the cases.
I would have chronographed the loads yesterday, but I was shooting in a steady drizzle. I'd like to see 3350 - 3400 fps. I'm going to be using the rifle this winter as my "Wolf Whacker". Where I live, there's no closed season and no bag limit on wolves.
I plan on getting out and continuing the ladder test with more powder in the case. My plan is to stop when I hit 0.0015" expansion, when I can't get any more powder in the case, or when I hit the desired velocity
Thoughts???..................Am I crazy??
ps: Test was fired using my Accumark rifle.
