Last time, Lil Gun gave great velocities but the variation was too high. Today I tried some minor tweaking to the Lil Gun load.
Same 180 gr. TCGC bullet with the short bore riding section, HTWW, sized 0.358", felix lube.
The Mark II homemade peep site was used, but the elevation was way off. If I ever get the sight dialed in, then I'll move the target out to 100 yards.Standard deviation for 15 shots, ranked best to worst
1) 16.7 gr. Lil Gun, Fed #200, 0.72% or 13.4 fps
2) 16.2 gr. Lil Gun, CCI #500, 0.82% or 14.9 fps
3) 16.7 gr. Lil Gun, CCI #500, 1.39% or 25.7 fps
All loads gave acceptable standard deviation. I don't know what was different compared to last time. Velocity, ranked highest to lowest
1)16.7 gr. Lil Gun, Fed #200, 1863 fps
2)16.7 gr. Lil Gun, CCI #500, 1848 fps
3)16.2 gr. Lil Gun, CCI #500, 1804 fps
The magnum Fed #200 gave higher velocities than the standard CCI #500.Peak Pressure
1) 16.7 gr. Lil Gun, Fed #200, 35.5 ksi
2) 16.7 gr. Lil Gun, CCI #500, 34.4 ksi
3) 16.2 gr. Lil Gun, CCI #500, 32.0 ksi
The magnum primer also generated more pressure, but it may not be statistically significant.Accuracy for three 5-shot groups at 50 yards
1) 16.2 gr. Lil Gun, CCI #500, 1.73"
2) 16.7 gr. Lil Gun, CCI #500, 2.17"
3) 16.7 gr. Lil Gun, Fed #200, 3.37"
The accuracy results are misleading because the limiting factor is yours truly. I started out using the Steady Point rest -- 5" group. Then I chucked the Steady Point and just rested the gun on an old coat, and consistently got 2" groups, with the groups shrinking as more shots were fired just because I was refining my technique.
Since last time, I remounted the strain gage connector so that the cable no longer runs close to the muzzle. However, every string had at least one bogus trace no matter how I routed the cable.
Velocities are great, so I think I need to stop worrying about load development and focus instead on getting the sight dialed in and refining my shooting technique.