QUESTION: Based on the data that I have provided herein, what might be the reason my SD/ES numbers are generally worse w/ H4350 compared to IMR 4350? And what would you do to fix it/diagnose the issue.
Background info for all the questions I can foresee coming:
Cartridge: 6.5 Creedmoor w/ CCI #200 primers, Berger 140gr Hybrid Target bullets, Lapua LRP brass. H4350/IMR4350. CBTO 2.187" mag length.
Rifle: Howa 1500 KRG Bravo w/ MPOD, rear bag rest and Vortex Diamondback 6-24x50 scope. Decent groups for a factory rifle. Non-stainless barrel.
I don't have the IMR 4350 anymore and do not want to go back to it because it's too hard to find and I already got lucky once with 8lbs of H4350.
I have not done a seating depth test. I do that after I find my powder charge. I know some like to do it the other way around. That's fine. All groups in the data are 4 shot groups @100 yards. All powder charges were measured on a digital scale that returned to zero every time, and maintained its calibration throughout the reloading process. Cartridges were not cooked in the chamber or direct sunlight and only loaded into the chamber single shot style when I was steady.
Load Process For 0x Fired Lapua LRP & IMR4350: The total indicated runout (TIR) on the necks was ALL within 0.001" if not less. The factory brass was left untouched as it was before I had my carbide expander mandrel, but all cases we're measuring neck O.D. of 0.289" +/- 0.0005". Bullets were not sorted by base to ogive. Bullets seated w/ Forster Ultra Micrometer. TIR on the loaded bullet was negligible. Most all of them within 0.001" very few 0.002".
Load Process For 2x Fired Lapua LRP & H4350: First deprimed, then wet tumbled w/ SS media+dawn+lemi-shine, then AMP annealed (every firing), then resized on a Lee turret w/ .289" TiN coated bushing in a Redding FL bushing die, then expanded with a .263" Sinclair carbide expander mandrel and after spring back, left me at .290" neck O.D. again +/- 0.0005". Loaded cartridge neck O.D. is .292". TIR with these brass necks is all within 0.0025" and that only shows up after using the bushing die. The bushing is floating as per the instructions. Bullet runout was within 0.004". Bullets WERE sorted by base to ogive and seated with the Forster Micrometer. (Base to ogive only varied by 0.003").
Current Plan of Action: I plan on testing the 41.0gr of H4350 to see if it holds true and if it doesn't, I plan on getting a Forster Co-Ax and a Forster honed die, and then re-testing the same powder charges to see if the Lee Turret + Bushing induced TIR caused the degrade in SD/ES. If that doesn't show improvement, I plan on testing the same powder charges with factory brass to see if something else in my reloading process is causing the error or if it is just the powder.
EDIT: I just realised that my good nodes for both IMR 4350, and H4350 we're both dead on 2,700fps. Thought it was interesting. (41.8gr IMR 4350 and 41.3gr H4350)
Here is the data:
Background info for all the questions I can foresee coming:
Cartridge: 6.5 Creedmoor w/ CCI #200 primers, Berger 140gr Hybrid Target bullets, Lapua LRP brass. H4350/IMR4350. CBTO 2.187" mag length.
Rifle: Howa 1500 KRG Bravo w/ MPOD, rear bag rest and Vortex Diamondback 6-24x50 scope. Decent groups for a factory rifle. Non-stainless barrel.
I don't have the IMR 4350 anymore and do not want to go back to it because it's too hard to find and I already got lucky once with 8lbs of H4350.
I have not done a seating depth test. I do that after I find my powder charge. I know some like to do it the other way around. That's fine. All groups in the data are 4 shot groups @100 yards. All powder charges were measured on a digital scale that returned to zero every time, and maintained its calibration throughout the reloading process. Cartridges were not cooked in the chamber or direct sunlight and only loaded into the chamber single shot style when I was steady.
Load Process For 0x Fired Lapua LRP & IMR4350: The total indicated runout (TIR) on the necks was ALL within 0.001" if not less. The factory brass was left untouched as it was before I had my carbide expander mandrel, but all cases we're measuring neck O.D. of 0.289" +/- 0.0005". Bullets were not sorted by base to ogive. Bullets seated w/ Forster Ultra Micrometer. TIR on the loaded bullet was negligible. Most all of them within 0.001" very few 0.002".
Load Process For 2x Fired Lapua LRP & H4350: First deprimed, then wet tumbled w/ SS media+dawn+lemi-shine, then AMP annealed (every firing), then resized on a Lee turret w/ .289" TiN coated bushing in a Redding FL bushing die, then expanded with a .263" Sinclair carbide expander mandrel and after spring back, left me at .290" neck O.D. again +/- 0.0005". Loaded cartridge neck O.D. is .292". TIR with these brass necks is all within 0.0025" and that only shows up after using the bushing die. The bushing is floating as per the instructions. Bullet runout was within 0.004". Bullets WERE sorted by base to ogive and seated with the Forster Micrometer. (Base to ogive only varied by 0.003").
Current Plan of Action: I plan on testing the 41.0gr of H4350 to see if it holds true and if it doesn't, I plan on getting a Forster Co-Ax and a Forster honed die, and then re-testing the same powder charges to see if the Lee Turret + Bushing induced TIR caused the degrade in SD/ES. If that doesn't show improvement, I plan on testing the same powder charges with factory brass to see if something else in my reloading process is causing the error or if it is just the powder.
EDIT: I just realised that my good nodes for both IMR 4350, and H4350 we're both dead on 2,700fps. Thought it was interesting. (41.8gr IMR 4350 and 41.3gr H4350)
Here is the data:
Attachments
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