I jumped at the chance to shoot without pouring rain, soggy targets and howling wind... I also wanted a chance to confirm my earlier findings. Here is how it went.
Weather; overcast and calm wind.
Rifle: Marlin 336 Cowboy conversion - Caliber 30-30
Started out at the 50 yard range with a cold clean bore using the SR4756 load (~1400 fps)/ Ranch Dog TLC 311-165 RF bullet to confirm the zero I had established on the previous range trip. The first shot was about 2" high, the next shot was 1" high and the next three made a nice little <7/8" triangle right at point of aim.
I fired another five shot group with the same load and it too shot point of aim but expanded to 1-1/8". Then another that printed POA inside of 7/8". This is the load I will use for for the Levergun Silhouette matches. Using the 5th notch and holding at the top of the back of the 200 yard Rams, it should topple them if I do my part.
Next up was a middle of the road load using the same excellent Ranch Dog TLC 311-165 RF bullet - weighs in at 177 grains with this alloy, lubed and gas checked over Hercules 2400 powder (current versions of this powder are now made by Alliant). Using the same sight setting as the previous load (3rd notch up from the bottom on the elevator ramp) this load printed 5" higher at 50 yards. The first three shots formed a 2" triangle centered on the bullseye. Adjusting the rear sight to the second notch the next 5 shot group printed 2-1/2" above the point of aim into a 2" group. Not exactly the accuracy I was hoping for but well within the realm of minute of Deer vitals out well beyond what I'd take a shot on a critter. Using Veral Smith's formula this load should also penetrate more than 40" of critter minus bones. A quartering away shot through the boiler room and the offside shoulder should produce a dead Deer sized critter within rock throwing distance of the hit.
A load that continues to impress is the 170 grain Oregon Trail Laser-Cast bullet over 5 grains of Red Dot powder. This load produced the best group of the day just over 1/2". Using the zero for the SR4756 load it prints 2" higher and 1" to the right. This load averages 1047 fps.
The Lee C309-113 F "Soup Can" bullet over 2.8 grains (a .3 cc Lee powder Scoop) produced 1-1/8" accuracy at 50 yards and using the SR4756 load zero printed the slightly left (~1/2") of Point of Aim. This load looks like it will be my "Grouse load" for this rifle. At 25 yards it prints ~1" above point of aim, putting the bead at the base of the neck should produce a clean kill with no destruction of the delicious meat. When hunting with this rifle I will have at least a Grouse limit's worth in my pocket. The report is rimfire like and the recoil non existent.
Returning to the SR4756 load it appears the 100 yard Zero is right at or just above the 4th notch. I did not shoot enough groups at this range to confirm that. Using my ballistic software I can estimate that the 150 yard zero is on the 5th notch and the 200 yard zero should be just below the sixth (top) notch.
I also shot two groups worth off hand. The front bead just hangs on the target and I was able to call my shots. It will give me NO excuses in the matches for misses... Good problem.
I am very pleased with the conversion and this rifle is fast becoming a favorite. Can't wait to get it back out to the range.