Today I planned to put the iron sights back on, sight in the Marlin for the 180 grain load, and shoot 357's happily ever after. But Mr. Murphy had other ideas.
I had planned to install a taller front sight blade, but when I went to tap the old blade out, the entire front ramp fell off the barrel. Long story there dating back to when I first got the Marlin -- the factory sight ramp was crooked, so I had replaced it with a Marble ramp, installed with a new single 6-48 screw plus silver solder for insurance. It was the first time I'd ever silver soldered a ramp and I had a difficult time with it. Nonetheless, the ramp had held up for 10 or so years .... until today.
The 6-48 threads had corroded and stripped out, so I had to D&T the hole to 8-40. I'm not going to try silver soldering the ramp again, instead I'll use JB weld and the single screw. But I have to order the 8-40 screw. While I'm waiting, I installed yet another scope, this time a Mueller 4.5-14. The Mueller was intended for a TC carbine build, but I'm still waiting on parts for the TC.
Today I was playing with yet another variation on the 180 grain Loverider, not that there was anything wrong with the last version. I also shot up some old loads that I had laying around.
The latest Loverider compared to the "old" 190 grain bullet. 5-shot groups at 100 yards:
180 Loverider, 16.8 WC297, WSRM, HVR, heat treated WW, average 1794 fps, 1.04% standard deviation
7.3", 2.9", 3.35", 4.15", 5.5", 4.4", 3.6", 3.9', AVERAGE 4.26"
190 gr. 80% meplat, 15.3 Lil Gun, about 1700 fps, 1.52% standard deviation
6.05", 2.5", 1.8", 2.8", 4.7", 3.505", 2.4", AVERAGE 3.39"
190 gr. 75% meplat, 15.3 Lil Gun, about 1680 fps3.6"
160 gr. GC, 80% meplat, 6.8 gr. Unique, about 1300 fps3.1"
180 gr. Speer FMJ, 12.5 gr. 2400, about 1430 fps
4.5", 6.3", AVERAGE 5.4"
The funny thing is that I had abandoned the 80% meplat years ago because I couldn't get good accuracy out of it, yet today it shot some decent groups.Conclusions:
I take some consolation from my cast bullets outshooting the jacketed bullet.
Even though the 190 gr. 80% meplat outshot the 180 gr. today, the difference was not statistically significant according to a t-test. http://www.graphpad.com/quickcalcs/ttest1.cfm
I was reminded that the Marlin is not an easy gun to shoot from a benchrest -- it literally 'jumps," and sometimes twists, when fired from a rest. I could usually predict whether a shot would open up the group just by the way the gun recoiled. If it jumped and twisted, accuracy tended to be poor. If it recoiled straight back, accuracy tended to be better. I had best luck pulling the gun tight against my shoulder instead of letting it slide on the bags. But it was challenging to pull it tight exactly the same way every time.
I haven't decided whether I will try yet another bullet design. SInce the 80% meplat seems to shoot as well as anything, it's tempting to switch back to an 80% meplat. Perhaps I'll split the weight difference and go with 185 grains at 1750 fps ?
If I ever win the lottery, a new barrel with a better chamber is on my wish list. In the meantime, I'm working on building a custom TC carbine barrel chambered for 357 with a proper throat. I'm curious to see what my 357 cast bullets will do when launched from a good throat.