Remarks:
While the load data I used here falls within published load data in multiple manuals, use caution with this load as I am working up towards max allowed pressure. At the low and high ends of the charge weights tested, the velocities were very close to the GRT model data. There was a large jump in velocity (130fps) between 27.5 and 28.0 grains. This is a load combination that I will be exploring further in my 18″ barrel in the future where I would expect 100% powder burn..
Objective:
This rifle is my primary hunting rifle, especially for deer. For this setup, my goal is to develop a hunting load that is effective up to 200+ yards. With this bullet, I need to achieve a MV of at least 2,200 fps to ensure the bullet will deliver at least 1,000 ft/lbs of energy past 200 yards. With this load work up, I’m looking to balance max accuracy with max velocity.
Conditions:
- Date: 4/19/22
- Temperature: 60F
- Wind: 10-15mph
Firearm:
- Barrel: PSA 12” 1:7 Twist
- Upper: PSA
- Lower: PSA
- Lower Parts: PSA
- Trigger: Larue MBT-2
Components:
- Bullet: Hornady 123 gr SST – G1 B.C.: 0.510
- Powder: Hodgdon Varget
- Primer: CCI #400
- Brass: Hornady
- Dies: Lee Pacesetter 3-die set
- Chronograph: Caldwell Ballistic Precision
Measurements:
- Case Trim Length: 1.510
- C.O.L.: 2.245
- C.B.T.O: 1.678
Load / Model Data:
- Gordons Reloading Tool Data
- Charge Data
- GRT Pressure Curve
- Expected Ballistics Table
- Expected Bullet Drop
Results:
- 26.5 Grains
- 27.0 Grains (This is the load I would use)
- 27.5 Grains
- 28.0 Grains
- 28.5 Grains
- Optimal Ballistics Table
- Optimal Bullet Drop
Summary:
At the highest charge weights, I was seeing sufficient velociites but the groups started opening up. With 27.0 grains @ 2,054fps & 1.30moa, this round would be effectic to around 150 yards which is plenty enough for hunting on my property. There were no pressure signs on my brass but I was already working with compressed loads, so I don’t think there is any room to increase the charge weight.